How-To Tutorials

Opening the RadRails Views Some of the views that we will go through in this article are available as part of the Rails default perspective, which means you don't need to do anything special to open them; they will appear as tabbed views in a pane at the bottom of your workbench. Just look for the tab name of the view you want to see and click on it to make it visible. However, there are some views that are not opened by default, or maybe you closed them at some point accidentally, or maybe you changed to the Debug perspective and you want to display some of the RadRails views there. When you need to open a view whose tab is not displaying, you can go to the Window menu, and select the Show View option. If you are in the Rails perspective, all the available views will be displayed in that menu, as you can see in the screenshot above. When opening this menu from a different perspective, you will not see the RadRails views here, but you can select Other.... If this is the case, in the Show View dialog, most of the views will appear under the Ruby category, except for the Generators, Rails API, and Rake Tasks views, which are located under Rails. Documentation Views As happens with any modern programming language, Ruby has an extensive API. There are lots of libraries and classes and even with Ruby being an intuitive language with a neat consistent API, often we need to read the documentation. As you probably know, Ruby provides a standard documentation format called RDoc, which uses the comments in the source code to generate documentation. We can access this RDoc documentation in different ways, mainly in HTML format through a browser or by using the command-line tool RI. This produces a plain-text output directly at the command shell, in a similar way to the man command in a UNIX system. RadRails doesn't add any new functionality to the built-in documentation, but provides some convenient views so we can explore it without losing the context of our project's source. Ruby Interactive (RI) View This view provides a fast and comfortable way of browsing the local documentation in the same way as you would use RI from the command line. You can look either for a class or a method name. Just start typing at the input box at the top left corner of the view and the list below will display the matching entries. That's a nice improvement over the command line interface, since you can see the results as you type instead of having to run a complete search every time. If you know the name of both the class and the method you are looking for, then you can write them using the hash (pound) sign as a separator. For example, to get the documentation for the sum method of the class Enumerable you would write Enumerable#sum. The documentation will display in the right pane, with a convenient highlighting of the referenced methods and classes. Even if the search results of RI don't look very attractive compared to the output of the HTML-based documentation views, RI has the advantage of searching locally on your computer, so you can use it even when working off-line. Ruby Core, Ruby Standard Library, and Rails API There are three more views related to documentation in RadRails: Ruby Core API, Ruby Standard Library API, and Rails API. Unlike the RI view, these ones look for the information over the Internet, so you will not be able to use them unless you are on-line. On the other hand, the information is displayed in a more attractive way than with RI, and it provides links to the source code of the consulted methods, so if the documentation is not enough, you can always take a look at the inner details of the implementation. The Ruby Core API view displays the documentation of the classes included in Ruby's core. These are the classes you can directly use without a previous require statement. The documentation rendered is that at http://www.ruby-doc.org/core/. You are probably familiar with this type of layout, since it's the default RDoc output. The upper pane displays the navigation links, and the lower pane shows the detail of the documentation. The navigation is divided into three frames. The one to the left shows the files in which the source code is, the one in the middle shows the Classes and Modules, and in the third one you can find all the methods in the API. The Ruby Standard Library API is composed of all the classes and modules that are not a part of Ruby's core, but are typically distributed as a part of the Ruby installation. You can directly use these classes after a require statement in your code. The Ruby Standard Library API View displays the information from http://www.ruby-doc.org/stdlib. In this case, the navigation is the same as in Ruby Core, but with an additional area to the left, in which you can see all the available packages (the ones you would require for using the classes within your code). When you select a package link, you will see the files, classes, and methods for that single package. The last of the documentation views displays information about the Rails API. It includes the documentation of ActiveRecord, the ActionPack, ActiveSupport, and the rest of the Rails components. The information is obtained from http://api.rubyonrails.org. In this case the layout is slightly different because the information about the files, classes, and methods is displayed to the left instead at the top of the view. Apart from that, the behavior is identical to that of the Ruby Core API view. Since some of the API descriptions are fairly long, it can be convenient to maximize the documentation views when you are using them. Remember you can maximize any of the views by double-clicking its tab or by using the maximize icon on the view's toolbar. Double-clicking again will restore the view to the original size and position.

Our Target Module: What We Want Before we begin developing a module, here's a brief overview of what we want to accomplish. The module we will write in this article is the Philosophy Quotes module (philquotes will be our machine-readable name). The goal of this module will be to create a block that displays pithy philosophical quotes. We will implement the following features: Quotes should be stored along with other basic content, making it possible to add, modify, and delete this content in exactly the same way that we create other articles. Since our existing themes aren't aware of this quotes module, it must provide some default styling. We will progress through the creation of this module by first generating a new "quote" content type, and then building a theme-aware module. Creating a Custom Content Type As Drupal evolved, it incorporated an increasingly sophisticated method for defining content. Central to this system is the idea of the content type. A content type is a definition, stored in Drupal's database, of how a particular class of content should be displayed and what functionality it ought to support. Out of the box, Drupal has two defined content types: Page and Story. Pages are intended to contain content that is static, like an "About Us" or "Contact Us" page. Stories, on the other hand, are intended to contain more transient content—news items, blog postings, and so on. Creating new pages or stories is as simple as clicking on the Create Content link in the default menu. Obviously, not all content will be classified as either a page or a story, and many sites will need specialized content types to adequately represent a specific class of content. Descriptions of events, products, component descriptions, and so on might all be better accomplished with specialized content types. Our module is going to display brief quotes. These quotes shouldn't be treated like either articles or pages. For example, we wouldn't want a new quote to be displayed along with site news in the center column of our front page. Thus, our quotes module needs a custom content type. This content type will be very simple. It will have two parts: the text of the quote and the origin of the quote. For example, here's a famous quote: The life of man [is] solitary, poor, nasty, brutish, and short.—Thomas Hobbes. The text of this quote is "The life of man [is] solitary, poor, nasty, brutish, and short", and the origin in this example is Thomas Hobbes. We could have been more specific and included the title of the work (Leviathan) or even the exact page reference, edition, and so on. But all this information, in our simple example, would be treated as the quote's origin. Given the simplicity of our content type, we can simply use the built-in Drupal content type tool to create the new type. To generate even more sophisticated content types, we could install the CCK (Content Creation Kit) module, and perhaps some of the CCK extension modules. CCK provides a robust set of tools for defining custom fields, data types, and features. But here our needs are simple, so we won't need any additional modules or even any custom code to create this new content type. Using the Administration Interface to Create a Content Type The process of creating our custom content type is as simple as logging into Drupal and filling out a form. The content type tool is in Administer | Content management | Content types. There are a couple of tabs at the top of the page: Clicking the Add content type tab will load the form used to create our new content type. On this form, we need to complete the Name and Type fields—the first with a human-friendly name, and the second with a computer-readable name. Description is often helpful. In addition to these fields, there are a few other form fields under the Submission form settings and Workflow settings that we need to change. In the Submission form settings section, we will change the labels to match the terminology we have been using. Instead of Title and Body, our sections will be Origin and Text. Changing labels is a superficial change. While it changes the text that is displayed to users, the underlying data model will still refer to these fields as title and body. We will see this later in the article. In the Workflow settings section, we need to make sure that only Published is checked. By default, Promoted to front page is selected. That should be disabled unless you want new quotes to show up as content in the main section of the front page. Once the form is complete, pressing the Save content type button will create the new content type. That's all there is to it. The Create content menu should now have the option of creating a new quote: As we continue, we will create a module that displays content of type quote in a block. Before moving on, we want a few pieces of content. Otherwise, our module would have no data to display. Here's the list of quotes (as displayed on Administer | Content management | Content) that will constitute our pool of quotations for our module.  

Framework Solution The implementation of access control falls into three classes. One is the class that is asked questions about who can do what. Closely associated with this is another class that caches general information applicable to all users. It is made a separate class to aid implementation of the split of cache between general and user specific. The third class handles administration operations. Before looking at the classes, though, let's figure out the database design. Database for RBAC All that is required to implement basic RBAC is two tables. A third table is required to extend to a hierarchical model. An optional extra table can be implemented to hold role descriptions. Thinking back to the design considerations, the first need is for a way to record the operations that can be done on the subjects, that is the permissions. They are the targets for our access control system. You'll recall that a permission consists of an action and a subject, where a subject is defined by a type, and an identifier. For ease of handling, a simple auto-increment ID number is added. But we also need a couple of other things. To make our RBAC system general, it is important to be able to control not only the actual permissions, but also who can grant those permissions, and whether they can grant that right to others. So an extra control field is added with one bit for each of those three possibilities. It therefore becomes possible to grant the right to access something with or without the ability to pass on that right. The other extra data item that is useful is a "system" flag. It is used to make some permissions incapable of deletion. Although not being a logical requirement, this is certainly a practical requirement. We want to give administrators a lot of power over the configuration of access rights, but at the same time, we want to avoid any catastrophes. The sort of thing that would be highly undesirable would be for the top level administrator to remove all of their own rights to the system. In practice, most systems will have a critical central structure of rights, which should not be altered even by the highest administrator. So now the permissions table can be seen to be as shown in the following screenshot: Note that the character strings for role, action, and subject_type are given generous lengths of 60, which should be more than adequate. The subject ID will often be quite short, but to avoid constraining generality, it is made a text field, so that the RBAC system can still handle very complex identifiers, if required. Of course, there will be some performance penalties if this field is very long, but it is better to have a design trade-off than a limitation. If we restricted the subject ID to being a number, then more complex identifiers would be a special case. This would destroy the generality of our scheme, and might ultimately reduce overall efficiency. In addition to the auto-increment primary key ID, two indices are created, as shown in the following screenshot. They involve overhead during update operations but are likely to speed access operations. Since far more accesses will typically be made than updates, this makes sense. If for some reason an index does not give a benefit, it is always possible to drop it. Note that the index on the subject ID has to be constrained in length to avoid breaking limits on key size. The value chosen is a compromise between efficiency through short keys, and efficiency through the use of fine grained keys. In a heavily used system, it would be worth reviewing the chosen figure carefully, and perhaps modifying it in the light of studies into actual data. The other main database table is even simpler, and holds information about assignment of accessors to roles. Again, an auto-increment ID is added for convenience. Apart from the ID, the only fields required are the role, the accessor type, and the accessor ID. This time a single index, additional to the primary key, is sufficient. The assignment table is shown in the following screenshot, and its index is shown in the screenshot after that: Adding hierarchy to RBAC requires only a very simple table, where each row contains two fields: a role, and an implied role. Both fields constitute the primary key, neither field on its own being necessarily unique. An index is not required for efficiency, since the volume of hierarchy information is assumed to be small, and whenever it is needed, the whole table is read. But it is still a good principle to have a primary key, and it also guarantees that there will not be redundant entries. For the example given earlier, a typical entry might have consultant as the role, and doctor as the implied role. At present, Aliro implements hierarchy only for backwards compatibility, but it is a relatively easy development to make hierarchical relationships generally available. Optionally, an extra table can be used to hold a description of the roles in use. This has no functional purpose, and is simply an option to aid administrators of the system. The table should have the role as its primary key. As it does not affect the functionality of the RBAC at all, no further detail is given here. With the database design settled, let's look at the classes. The simplest is the administration class, so we'll start there. Administering RBAC The administration of the system could be done by writing directly to the database, since that is what most of the operations involve. There are strong reasons not to do so. Although the operations are simple, it is vital that they be handled correctly. It is generally a poor principle to allow access to the mechanisms of a system rather than providing an interface through class methods. The latter approach ideally allows the creation of a robust interface that changes relatively infrequently, while details of implementation can be modified without affecting the rest of the system. The administration class is kept separate from the classes handling questions about access because for most CMS requests, administration will not be needed, and the administration class will not load at all. As a central service, the class is implemented as a standard singleton, but it is not cached because information generally needs to be written immediately to the database. In fact, the administration class frequently requests the authorization cache class to clear its cache so that the changes in the database can be effective immediately. The class starts off: class aliroAuthorisationAdmin { private static $instance = __CLASS__; private $handler = null; private $authoriser = null; private $database = null; private function __construct() { $this->handler =& aliroAuthoriserCache::getInstance(); $this->authoriser =& aliroAuthoriser::getInstance(); $this->database = aliroCoreDatabase::getInstance(); } private function __clone() { // Enforce singleton } public static function getInstance() { return is_object(self::$instance) ? self::$instance : (self::$instance = new self::$instance()); } private function doSQL($sql, $clear=false) { $this->database->doSQL($sql); if ($clear) $this->clearCache(); } private function clearCache() { $this->handler->clearCache(); } Apart from the instance property that is used to implement the singleton pattern, the other private properties are related objects that are acquired in the constructor to help other methods. Getting an instance operates in the usual fashion for a singleton, with the private constructor, and clone methods enforcing access solely via getInstance. The doSQL method also simplifies other methods by combining a call to the database with an optional clearing of cache through the class's clearCache method. Clearly the latter is simple enough that it could be eliminated. But it is better to have the method in place so that if changes were made to the implementation such that different actions were needed when any relevant cache is to be cleared, the changes would be isolated to the clearCache method. Next we have a couple of useful methods that simply refer to one of the other RBAC classes: public function getAllRoles($addSpecial=false) { return $this->authoriser->getAllRoles($addSpecial); }public function getTranslatedRole($role) { return $this->authoriser->getTranslatedRole($role); } Again, these are provided so as to simplify the future evolution of the code so that implementation details are concentrated in easily identified locations. The general idea of getAllRoles is obvious from the name, and the parameter determines whether the special roles such as visitor, registered, and nobody will be included. Since those roles are built into the system in English, it would be useful to be able to get local translations for them. So the method getTranslatedRole will return a translation for any of the special roles; for other roles it will return the parameter unchanged, since roles are created dynamically as text strings, and will therefore normally be in a local language from the outset. Now we are ready to look at the first meaty method: public function permittedRoles ($action, $subject_type, $subject_id) { $nonspecific = true; foreach ($this->permissionHolders ($subject_type, $subject_id) as $possible) { if ('*' == $possible->action OR $action == $possible->action) { $result[$possible->role] = $this->getTranslatedRole ($possible->role); if ('*' != $possible->subject_type AND '*' != $possible_subject_id) $nonspecific = false; } } if (!isset($result)) { if ($nonspecific) $result = array('Visitor' => $this->getTranslatedRole('Visitor')); else return array(); } return $result; }private function &permissionHolders ($subject_type, $subject_id) { $sql = "SELECT DISTINCT role, action, control, subject_type, subject_id FROM #__permissions"; if ($subject_type != '*') $where[] = "(subject_type='$subject_type' OR subject_type='*')"; if ($subject_id != '*') $where[] = "(subject_id='$subject_id' OR subject_id='*')"; if (isset($where)) $sql .= " WHERE ".implode(' AND ', $where); return $this->database->doSQLget($sql); } Any code that is providing an RBAC administration function for some part of the CMS is likely to want to know what roles already have a particular permission so as to show this to the administrator in preparation for any changes. The private method permissionHolders uses the parameters to create a SQL statement that will obtain the minimum relevant permission entries. This is complicated by the fact that in most contexts, asterisk can be used as a wild card. The public method permittedRoles uses the private method to obtain relevant database rows from the permissions table. These are checked against the action parameter to see which of them are relevant. If there are no results, or if none of the results refer specifically to the subject, without the use of wild cards, then it is assumed that all visitors can access the subject, so the special role of visitor is added to the results. When actual permission is to be granted we need the following methods: public function permit ($role, $control, $action, $subject_type, $subject_id) { $sql = $this->permitSQL($role, $control, $action, $subject_type, $subject_id); $this->doSQL($sql, true); }private function permitSQL ($role, $control, $action, $subject_type, $subject_id) { $this->database->setQuery("SELECT id FROM #__permissions WHERE role='$role' AND action='$action' AND subject_type='$subject_type' AND subject_id='$subject_id'"); $id = $this->database->loadResult(); if ($id) return "UPDATE #__permissions SET control=$control WHERE id=$id"; else return "INSERT INTO #__permissions (role, control, action, subject_type, subject_id) VALUES ('$role', '$control', '$action', '$subject_type', '$subject_id')"; } The public method permit grants permission to a role. The control bits are set in the parameter $control. The action is part of permission, and the subject of the action is identified by the subject type and identity parameters. Most of the work is done by the private method that generates the SQL; it is kept separate so that it can be used by other methods. Once the SQL is obtained, it can be passed to the database, and since it will normally result in changes, the option to clear the cache is set.   The SQL generated depends on whether there is already a permission with the same parameters, in which case only the control bits are updated. Otherwise an insertion occurs. The reason for having to do a SELECT first, and then decide on INSERT or UPDATE is that the index on the relevant fields is not guaranteed to be unique, and also because the subject ID is allowed to be much longer than can be included within an index. It is therefore not possible to use ON DUPLICATE KEY UPDATE. Wherever possible, it aids efficiency to use the MySQL option for ON DUPLICATE KEY UPDATE. This is added to the end of an INSERT statement, and if the INSERT fails by virtue of the key already existing in the table, then the alternative actions that follow ON DUPLICATE KEY UPDATE are carried out. They consist of one or more assignments, separated by commas, just as in an UPDATE statement. No WHERE is permitted since the condition for the assignments is already determined by the duplicate key situation. A simple method allows deletion of all permissions for a particular action and subject: public function dropPermissions ($action, $subject_type, $subject_id) { $sql = "DELETE FROM #__permissions WHERE action='$action' AND subject_type='$subject_type'AND subject_id='$subject_id' AND system=0"; $this->doSQL($sql, true); } The final set of methods relates to assigning accessors to roles. Two of them reflect the obvious need to be able to remove all roles from an accessor (possibly preparatory to assigning new roles) and the granting of a role to an accessor. Where the need is to assign a whole set of roles, it is better to have a method especially for the purpose. Partly this is convenient, but it also provides an extra operation, minimization of the set of roles. The method is: public function assign ($role, $access_type, $access_id, $clear=true) { if ($this->handler->barredRole($role)) return false; $this->database->setQuery("SELECT id FROM #__assignments WHERE role='$role' AND access_type='$access_type' AND access_id='$access_id'"); if ($this->database->loadResult()) return true; $sql = "INSERT INTO #__assignments (role, access_type, access_id) VALUES ('$role', '$access_type', '$access_id')"; $this->doSQL($sql, $clear); return true; }public function assignRoleSet ($roleset, $access_type, $access_id) { $this->dropAccess ($access_type, $access_id); $roleset = $this->authoriser->minimizeRoleSet($roleset); foreach ($roleset as $role) $this->assign ($role, $access_type, $access_id, false); $this->clearCache(); }public function dropAccess ($access_type, $access_id) { $sql = "DELETE FROM #__assignments WHERE access_type='$access_type' AND access_id='$access_id'"; $this->doSQL($sql, true); } The method assign links a role to an accessor. It checks for barred roles first, these are simply the special roles discussed earlier, which cannot be allocated to any accessor. As with the permitSQL method, it is not possible to use ON DUPLICATE KEY UPDATE because the full length of the accessor ID is not part of an index, so again the existence of an assignment is checked first. If the role assignment is already in the database, there is nothing to do. Otherwise a row is inserted, and the cache is cleared. Getting rid of all role assignments for an accessor is a simple database deletion, and is implemented in the dropAccess method. The higher level method assignRoleSet uses dropAccess to clear out any existing assignments. The call to the authorizer object to minimize the role set reflects the implementation of a hierarchical model. Once there is a hierarchy, it is possible for one role to imply another as consultant implied doctor in our earlier example. This means that a role set may contain redundancy. For example, someone who has been allocated the role of consultant does not need to be allocated the role of doctor. The minimizeRoleSet method weeds out any roles that are superfluous. Once that has been done, each role is dealt with using the assign method, with the clearing of the cache saved until the very end. The General RBAC Cache As outlined earlier, the information needed to deal with RBAC questions is cached in two ways. The file system cache is handled by the aliroAuthoriserCache singleton class, which inherits from the cachedSingleton class. This means that the data of the singleton object will be automatically stored in the file system whenever possible, with the usual provisions for timing out an old cache, or clearing the cache when an update has occurred. It is highly desirable to cache the data both to avoid database operations and to avoid repeating the processing needed in the constructor. So the intention is that the constructor method will run only infrequently. It contains this code: protected function __construct() { // Making private enforces singleton $database = aliroCoreDatabase::getInstance(); $database->setQuery("SELECT role, implied FROM #__role_link UNION SELECT DISTINCT role, role AS implied FROM #__assignments UNION SELECT DISTINCT role,role AS implied FROM #__permissions"); $links = $database->loadObjectList(); if ($links) foreach ($links as $link) { $this->all_roles[$link->role] = $link->role; $this->linked_roles[$link->role][$link->implied] = 1; foreach ($this->linked_roles as $role=>$impliedarray) { foreach ($impliedarray as $implied=>$marker) { if ($implied == $link->role OR $implied == $link->implied) { $this->linked_roles[$role][$link->implied] = 1; if (isset($this->linked_roles[$link->implied])) foreach ($this->linked_roles[$link->implied] as $more=>$marker) { $this->linked_roles[$role][$more] = 1; } } } } } $database->setQuery("SELECT role, access_id FROM #__assignments WHERE access_type = 'aUser' AND (access_id = '*' OR access_id = '0')"); $user_roles = $database->loadObjectList(); if ($user_roles) foreach ($user_roles as $role) $this- >user_roles[$role->access_id][$role->role] = 1; if (!isset($this->user_roles['0'])) $this->user_roles['0'] = array(); if (isset($this->user_roles['*'])) $this->user_roles['0'] = array_merge($this->user_roles['0'], $this->user_roles['*']); } All possible roles are derived by a UNION of selections from the permissions, assignments, and linked roles database tables. The union operation has overheads, so that alone is one reason for favoring the use of a cache. The processing of linked roles is also complex, and therefore worth running as infrequently as possible. Rather than working through the code in detail, it is more useful to describe what it is doing. The concept is much simpler than the detail! If we take an example from the backwards compatibility features of Aliro, there is a role hierarchy that includes the role Publisher, which implies membership of the role Editor. The role Editor also implies membership of the role Author. In the general case, it is unreasonable to expect the administrator to figure out the implied relationships. In this case, it is clear that the role Publisher must also imply membership of the role Editor. But these linked relationships can plainly become quite complex. The code in the constructor therefore assumes that only the least number of connections have been entered into the database, and it figures out all the implications. The other operation where the code is less than transparent is the setting of the user_roles property. The Aliro RBAC system permits the use of wild cards for specification of identities within accessor, or subject types. An asterisk indicates any identity. For accessors whose accessor type is user, another wild card available is zero. This means any user who is logged in, and is not an unregistered visitor. Given the relatively small number of role assignments of this kind, it saves a good deal of processing if all of them are cached. Hence the user_roles processing is done in the constructor. Other methods in the cache class are simple enough to be mentioned rather than given in detail. They include the actual implementation of the getTranslatedRole method, which provides local translations for the special roles. Other actual implementations are getAllRoles with the option to include the special roles, getTranslatedRole, which translates a role if it turns out to be one of the special ones and barredRole, which in turn, tests to see if the passed role is in the special group. It may therefore not be assigned to an accessor.

The Purpose of the Facebook Platform As you develop your Facebook applications, you'll find that the Facebook Platform is essential—in fact you won't really be able to do anything without it. So what does it do? Well, before answering that, let's look at a typical web-based application. The Standard Web Application Model If you've ever designed and built a web application before, then you'd have done it in a fairly standard way. Your application and any associated data would have been placed on a web server, and then your application users will access it from their web browsers via the Internet: The Facebook model is slightly different. The Facebook Web Application Model As far as your application users are concerned, they will just access Facebook.com and your application, by using a web browser and the Internet. But, that's not where the application lives—it's actually on your own server: Once you've looked at the Facebook web application model and realized that your application actually resides on your own server, it becomes obvious what the purpose of the Facebook Platform is—to provide an interface between your application and itself. There is an important matter to be considered here. If the application actually resides on your server, and your application becomes very successful (according to Facebook there are currently 25 million active users), then will your server be able to able to cope with that number of hits? Don't be too alarmed. This doesn't mean that your server will be accessed every time someone looks at his or her profile. Facebook employs a cache to stop that happening: Of course, at this stage, you're probably more concerned with just getting the application working—so let's continue looking at the Platform, but just bear that point in mind. Different components of the Facebook platform There are three elements to the Facebook Platform: The Facebook API (Application Programming Interface) FBML—Facebook Markup Language FQL—Facebook Query Language We'll now spend some time with each of these elements, and you'll see how you can use them individually, and in conjunction to make powerful yet simple applications. The great thing is that if you haven't got your web server set up yet, don't worry, because Facebook supplies you with all of the tools that you would need in order to do a test run with each of the elements. The Facebook API If you've already done some programming, then you'll probably know what an API (or Application Programming Interface) is. It's a set of software libraries that enable you to work with an application (in this case, Facebook) without knowing anything about its internal workings. All you have to do is obtain the libraries, and start making use of them in your own application. Now, before you start downloading files, you can actually learn more about their functionality by making use of the Facebook API Test Console. The Facebook API Test Console If you want to make use of the Facebook Test Console, you'll first need to access the Facebook developers' section—you'll find a link to this at the bottom of every Facebook page: Alternatively, you can use the URL http://developers.facebook.com to go there directly in your browser. When you get to this page, you'll find a link to the Tools page: Or, again, you can go directly to http://developers.facebook.com/tools.php, where you'll find the API Test Console: You'll find that the API Test Console has a number of fields: User ID—A read-only field which (when you're logged on to Facebook) unsurprisingly displays your user ID number. Response Format—With this, you can select the type of response that you want, and this can be: XML JSON Facebook PHP Client Callback—If you are using XML or JSON, then you can encapsulate the response in a function. Method—The actual Facebook method that you want to test. Once you've logged in, you'll see that your User ID is displayed and that all the drop-downs are enabled: You will also notice that a new link, documentation, appears on the screen, which is very useful. All you have to do is to select a method from the drop-down list, and then click on documentation. Once you've done that you'll see: A description of the method The parameters used by the method An example return XML A description of the expected response. The FQL equivalent (we will discuss this later in the chapter.) Error codes For now, let's just change the Response Format to Facebook PHP Client, and then click on Call Method to see what happens: In this case, you can see that the method returns an array of user ids—each one is the ID of one of the friends of the currently logged in user (that is your list of friends because you're the person logged in). You could, of course, go on to use this array in PHP as part of your application, but don't worry about that at the moment. For the time being, we'll just concentrate on working with our prototyping in the test console. However, before we move on, it's worth noting that you can obtain an array of friends only for the currently logged in user. You can't obtain the list of friends for any other user. So, for example, you would not be able to use friends. get on id 286601116 or 705175505. In fact, you wouldn't be able to use friends. get for 614902533 (as shown in the example) because that's my ID and not yours. On the other hand, having obtained a list of valid IDs we can now do something more interesting with them. For example, we can use the users.getinfo method to obtain the first name and birthday for particular users: As you can see, a multidimensional array is returned to your PHP code (if you were actually using this in an application). Therefore, for example, if you were to load the array into a variable $birthdays, then $birthdays[0][birthday] would contain January 27, 1960. Of course, in the above example, the most important piece of information is the first birthday in the array—record that in your diary for future reference. And, if you're thinking that I'm old enough to be your father, well, in some cases this is actually true: Now that you've come to grips with the API Test console, we can turn our attention to FBML and the FBML Test Console.

Personal community is a dynamic feature of Liferay portal. By default, the personal community is a portal-wide setting that will affect all of the users. It would be nice to have more features in the personal community such as showing the most popular journal articles. This article by Jonas Yuan will address how to set up the most popular journal articles in you personalized community and view the counter for other assets. In a web site, we will have a lot of journal articles (that is, web content) for a given article type. For example, for the article type Article Content, we will have articles talking about product family. We may want to know how many times the end users read each article. Meanwhile, it would be nice if we could show the most popular articles (for example, TOP 10 articles) for this given article type. As shown in the following screenshot, a journal article My EDI Product I is shown via a portlet Ext Web Content Display. Rating and comments on this article are also exhibited. At the same time, the medium-size image, polls, and related content of this article are listed, too. A view counter of this article is especially displayed under the ratings. Moreover, the most popular articles are exhibited with article title and number of views under related content. All these articles belong to the article type article-content. That is, the article in the current portlet Ext Web Content Display has the most popular articles only for the article type article-content. Of course, you can customize the portlet Web Content Display directly through changing JSP files. For demo purposes, we will implement the view counter in the portlet Ext Web Content Display. Meanwhile, we will implement the mostly popular articles via VM services and article templates. In addition, we will analyze the view counter for other assets such as Image Gallery images, Document Library documents, Wiki articles, Blog entries, Message Boards threads, and so on. Adding a view counter in the Web Content Display portlet First of all, let's add a view counter in the Ext Web Content Display portlet. As the function of view counter for assets (including journal articles) is provided in the model TagsAssetModel of the com.liferay.portlet.tags.model package in the /portal/portal-service/src folder, we could use this feature in this portlet directly. To do so, use the following steps: Create a folder journal_content in the folder /ext/ext-web/docroot/html/portlet/. Copy the JSP file view.jsp in the folder /portal/portal-web/docroot/html/portlet/ to the folder /ext/ext-web/docroot/html/portlet/journal_content and open it. Add the line <%@ page import="com.liferay.portlet.tags.model.TagsAsset" %> after the line <%@ include file="/html/portlet/journal_content/init.jsp" %>, and check the following lines: JournalArticleDisplay articleDisplay = (JournalArticleDisplay) request.getAttribute( WebKeys.JOURNAL_ARTICLE_DISPLAY); if (articleDisplay != null) { TagsAssetLocalServiceUtil.incrementViewCounter( JournalArticle.class.getName(), articleDisplay.getResourcePrimKey());} Then add the following lines after the line <c:if test="<%=enableComments %>"> and save it: <span class="view-count"> <% TagsAsset asset = TagsAssetLocalServiceUtil.getAsset (JournalArticle.class.getName(), articleDisplay.getResourcePrimKey());%> <c:choose> <c:when test="<%= asset.getViewCount() == 1 %>"> <%= asset.getViewCount() %> <liferay-ui:message key="view" />, </c:when> <c:when test="<%= asset.getViewCount() > 1 %>"> <%= asset.getViewCount() %> <liferay-ui:message key="views" />, </c:when> </c:choose></span> The code above shows a way to increase the view counter via the TagsAssetLocalServiceUtil.incrementViewCounter method. This method takes two parameters className and classPK as inputs. For the current journal article, the two parameters are JournalArticle.class.getName() and articleDisplay.getResourcePrimKey(). Then, this code shows a way to display view counted through the TagsAssetLocalServiceUtil.getAsset method. Similarly, this method also takes two parameters, className and classPK, as inputs. This approach would be useful for other assets, as the className parameter could be Image Gallery, Document Library, Wiki, Blogs, Message Boards, Bookmark, and so on. Setting up VM service We can set up the VM service to exhibit the most popular articles. We can also add the getMostPopularArticles method in the custom velocity tool ExtVelocityToolUtil. To do so, first add the following method in the ExtVelocityToolService interface: public List<TagsAsset> getMostPopularArticles(String companyId, String groupId, String type, int limit); And then add an implementation of the getMostPopularArticles method in the ExtVelocityToolServiceImpl class as follows: public List<TagsAsset> getMostPopularArticles(String companyId, String groupId, String type, int limit) { List<TagsAsset> results = Collections.synchronizedList(new ArrayList<TagsAsset>()); DynamicQuery dq0 = DynamicQueryFactoryUtil.forClass( JournalArticle.class, "journalarticle"). setProjection(ProjectionFactoryUtil.property ("resourcePrimKey")).add(PropertyFactoryUtil. forName("journalarticle.companyId"). eqProperty("tagsasset.companyId")). add(PropertyFactoryUtil.forName( "journalarticle.groupId").eqProperty( "tagsasset.groupId")).add(PropertyFactoryUtil. forName("journalarticle.type").eq( "article-content")); DynamicQuery query = DynamicQueryFactoryUtil.forClass( TagsAsset.class, "tagsasset") .add(PropertyFactoryUtil.forName( "tagsasset.classPK").in(dq0)) .addOrder(OrderFactoryUtil.desc( "tagsasset.viewCount")); try{ List<Object> assets = TagsAssetLocalServiceUtil. dynamicQuery(query); int index = 0; for (Object obj: assets) { TagsAsset asset = (TagsAsset) obj; results.add(asset); index ++; if(index == limit) break; } } catch (Exception e){ return results; } return results; } The preceding code shows a way to get the most popular articles by company ID, group ID, article type, and limited articles to be returned. DynamicQuery API allows us to leverage the existing mapping definitions through access to the Hibernate session. For example, DynamicQuery dq0 selects the journal articles by companyID, groupId, and type; DynamicQuery query selects tagsassets by classPK, which exists in DynamicQuery dq0; and tagsassets are ordered by viewCount as well. Finally, add the following method to register the above method in ExtVelocityToolUtil: public List<TagsAsset> getRelatedArticles(String companyId, String groupId, String articleId, int limit){ return _extVelocityToolService.getRelatedArticles(companyId, groupId, articleId, limit);} The code above shows a generic approach to get TOP 10 articles for any article types. Of course, you can extend this approach to find TOP 10 assets. This can include Image Gallery images, Document Library documents, Wiki articles, Blog entries, Message Boards threads, Bookmark entries, slideshow, videos, games, video queue, video list, playlist, and so on. You may practice these TOP 10 assets feature. Building article template for the most popular journal articles We have added view counter on journal articles. We have already built VM service for the most popular articles too. Now let's build an article template for them. Setting up the default article type As mentioned earlier, there is a set of types of journal articles, for example, announcements, blogs, general, news, press-release, updates, article-tout, article-content, and so on. In real case, only some of these types will require view counter, for example article-content. Let's configure the default article type for mostly popular articles. We can add the following line at the end of portal-ext.properties. ext.most_popular_articles.article_type=article-content The code above shows that the default article type for most_popular_articles is article-content.

Gateways provide the connectivity required to reach other systems. These systems can be other sipXecs PBX's, traditional phone lines, or Internet Telephony Service Providers (ITSPs).Connecting the IP phone system to the outside world is one of the most difficult tasks in making the phone system work. If the network infrastructure is configured properly for quality of service, the connection to the outside world can most likely be the source of any call quality problems. Traditional analog Plain Old Telephone Service (POTS) lines are the largest source of frustration. If you can avoid them by utilizing a digital type of service or an ITSP, by all means take that avenue. For those not so lucky, you'll learn more about them then you ever thought you needed to. Typically, volume levels, line disconnect, and echo are the most common problems. Most gateways will have some advanced settings for dealing with these issues but they are different for every manufacturer. Adding gateways There are three types of gateways that can be configured to work in sipXecs; managed, unmanaged, and SIP Trunks. A managed gateway is a hardware device that connects to a traditional phone line. sipXecs knows how to generate configuration files (plug and play) for it. An unmanaged gateway is either a hardware device for which sipXecs doesn't know how to generate configuration files, or it may be another SIP PBX. A SIP Trunk is a connection to an ITSP. Managed gateways At present, there are eight gateways for which sipXecs generates configuration information (ACME 1000 and AudioCodes Models MP114, MP118, Mediant 1000/2000/3000/BRI, and TP260). This is just a small cross section of gateways available in the market. If your gateway is not in this list, see the following Unmanaged gateways subsection. The following detailed information about managed gateways may prove to be useful in setting up an unmanaged gateway. For the following example screens, we'll utilize an AudioCodes MP114 FXO (Foreign Exchange Office) gateway. This particular gateway has four analog ports for connecting to POTS lines. Information on the gateway is available at http://www.audiocodes.com/products/mediapack-1xx. To  add the gateway, click on the Gateways menu item in the  Devices menu. As shown in the following screenshot, there are no gateways configured by default. To add the gateway, click on the Gateways menu item in the Devices menu. As shown in the following screenshot, there are no gateways configured by default. To add a managed gateway, click on the Add new gateway drop-down box and select the appropriate gateway. The gateway configuration page will be displayed as follows: The following configuration information can be configured on this page (click on the Show Advanced Settings hyperlink to display all configuration items): Name: A name given to the gateway (no spaces). Address: The IP address of the gateway or the fully qualified hostname of the gateway (see manufacturer's documentation for information on configuring IP address and other basic settings). Port: An optional setting for UDP or TCP port if a non-standard port is used. Set to 0 to ignore this field. Transport protocol : This can be manually configured to UDP or TCP to force the SIP transport protocol. If it is set to Auto, the transport is determined through a DNS query. Serial Number : This is the Ethernet MAC address of the gateway. Firmware Version : Certain gateways may have different configuration file information or formats depending on the version of firmware in the device. Select the version of firmware that is loaded in the gateway (see manufacturer's documentation). Location: It is possible to restrict the gateway by selecting a specific location for which it can be used. A location is represented by a group of users. A user group must be created for every location that needs to be distinguished (remember that users can be in more than one group). This setting allows routing of calls based on the location or the user from which the call originates (source routing). This is useful if users located in a branch office would like to have a gateway preference so that calls are routed through their local gateway, for example, to preserve WAN bandwidth or to use caller ID offered by an analog gateway based on the PSTN number assigned to it. Only if that gateway is not available, will call routing fall back to other gateways specified for the corresponding dialing rule. Shared: If this setting is checked, this gateway can be used by any user in any location, even if a specific location is selected. This setting is checked by default so that users in an identified location still use their preferred gateway, but the gateway can also be used by other users in other locations. Description : This is for documenting the system configuration. Information about the lines connected to the gateway is very useful here. With all of the configuration information entered, click on the OK button and the Gateway page will be displayed as follows with the new gateway on it. Click on the gateway name to reveal more configuration options, as shown in the following screenshot: With all of the configuration information entered, click on the OK button and the Gateway page will be displayed as follows with the new gateway on it. Click on the gateway name to reveal more configuration options, as shown in the following screenshot: In the following subsections, we'll explore the managed gateway settings available.

MDX calculation performance Optimizing the performance of the Storage Engine is relatively straightforward: you can diagnose performance problems easily and you only have two options—partitioning and aggregation—for solving them. Optimizing the performance of the Formula Engine is much more complicated because it requires knowledge of MDX, diagnosing performance problems is difficult because the internal workings of the Formula Engine are hard to follow, and solving the problem is reliant on knowing tips and tricks that may change from service pack to service pack. Diagnosing Formula Engine performance problems If you have a poorly-performing query, and if you can rule out the Storage Engine as the cause of the problem, then the issue is with the Formula Engine. We've already seen how we can use Profiler to check the performance of Query Subcube events, to see which partitions are being hit and to check whether aggregations are being used; if you subtract the sum of the durations of all the Query Subcube events from the duration of the query as a whole, you'll get the amount of time spent in the Formula Engine. You can use MDX Studio's Profile functionality to do the same thing much more easily—here's a screenshot of what it outputs when a calculation-heavy query is run: The following blog entry describes this functionality in detail: http://tinyurl.com/mdxtrace; but what this screenshot displays is essentially the same thing that we'd see if we ran a Profiler trace when running the same query on a cold and warm cache, but in a much more easy-to-read format. The column to look at here is the Ratio to Total, which shows the ratio of the duration of each event to the total duration of the query. We can see that on both a cold cache and a warm cache the query took almost ten seconds to run but none of the events recorded took anywhere near that amount of time: the highest ratio to parent is 0.09%. This is typical of what you'd see with a Formula Engine-bound query. Another hallmark of a query that spends most of its time in the Formula Engine is that it will only use one CPU, even on a multiple-CPU server. This is because the Formula Engine, unlike the Storage Engine, is single-threaded. As a result if you watch CPU usage in Task Manager while you run a query you can get a good idea of what's happening internally: high usage of multiple CPUs indicates work is taking place in the Storage Engine, while high usage of one CPU indicates work is taking place in the Formula Engine. Calculation performance tuning Having worked out that the Formula Engine is the cause of a query's poor performance then the next step is, obviously, to try to tune the query. In some cases you can achieve impressive performance gains (sometimes of several hundred percent) simply by rewriting a query and the calculations it depends on; the problem is knowing how to rewrite the MDX and working out which calculations contribute most to the overall query duration. Unfortunately Analysis Services doesn't give you much information to use to solve this problem and there are very few tools out there which can help either, so doing this is something of a black art. There are three main ways you can improve the performance of the Formula Engine: tune the structure of the cube it's running on, tune the algorithms you're using in your MDX, and tune the implementation of those algorithms so they use functions and expressions that Analysis Services can run efficiently. We've already talked in depth about how the overall cube structure is important for the performance of the Storage Engine and the same goes for the Formula Engine; the only thing to repeat here is the recommendation that if you can avoid doing a calculation in MDX by doing it at an earlier stage, for example in your ETL or in your relational source, and do so without compromising functionality, you should do so. We'll now go into more detail about tuning algorithms and implementations. Mosha Pasumansky's blog, http://tinyurl.com/moshablog, is a goldmine of information on this subject. If you're serious about learning MDX we recommend that you subscribe to it and read everything he's ever written. Tuning algorithms used in MDX Tuning an algorithm in MDX is much the same as tuning an algorithm in any other kind of programming language—it's more a matter of understanding your problem and working out the logic that provides the most efficient solution than anything else. That said, there are some general techniques that can be used often in MDX and which we will walk through here. Using named sets to avoid recalculating set expressions Many MDX calculations involve expensive set operations, a good example being rank calculations where the position of a tuple within an ordered set needs to be determined. The following query includes a calculated member that displays Dates on the Rows axis of a query, and on columns shows a calculated measure that returns the rank of that date within the set of all dates based on the value of the Internet Sales Amount measure: WITH MEMBER MEASURES.MYRANK AS Rank ( [Date].[Date].CurrentMember ,Order ( [Date].[Date].[Date].MEMBERS ,[Measures].[Internet Sales Amount] ,BDESC ) )SELECT MEASURES.MYRANK ON 0 ,[Date].[Date].[Date].MEMBERS ON 1 FROM [Adventure Works] It runs very slowly, and the problem is that every time the calculation is evaluated it has to evaluate the Order function to return the set of ordered dates. In this particular situation, though, you can probably see that the set returned will be the same every time the calculation is called, so it makes no sense to do the ordering more than once. Instead, we can create a named set hold the ordered set and refer to that named set from within the calculated measure, so: WITH SET ORDEREDDATES AS Order ( [Date].[Date].[Date].MEMBERS ,[Measures].[Internet Sales Amount] ,BDESC ) MEMBER MEASURES.MYRANK AS Rank ( [Date].[Date].CurrentMember ,ORDEREDDATES ) SELECT MEASURES.MYRANK ON 0 ,[Date].[Date].[Date].MEMBERS ON 1 FROM [Adventure Works] This version of the query is many times faster, simply as a result of improving the algorithm used; the problem is explored in more depth in this blog entry: http://tinyurl.com/mosharank Since normal named sets are only evaluated once they can be used to cache set expressions in some circumstances; however, the fact that they are static means they can be too inflexible to be useful most of the time. Note that normal named sets defined in the MDX Script are only evaluated once, when the MDX script executes and not in the context of any particular query, so it wouldn't be possible to change the example above so that the set and calculated measure were defined on the server. Even named sets defined in the WITH clause are evaluated only once, in the context of the WHERE clause, so it wouldn't be possible to crossjoin another hierarchy on columns and use this approach, because for it to work the set would have to be reordered once for each column. The introduction of dynamic named sets in Analysis Services 2008 improves the situation a little, and other more advanced techniques can be used to work around these issues, but in general named sets are less useful than you might hope. For further reading on this subject see the following blog posts: http://tinyurl.com/chrisrankhttp://tinyurl.com/moshadsetshttp://tinyurl.com/chrisdsets Using calculated members to cache numeric values In the same way that you can avoid unnecessary re-evaluations of set expressions by using named sets, you can also rely on the fact that the Formula Engine can (usually) cache the result of a calculated member to avoid recalculating expressions which return numeric values. What this means in practice is that anywhere in your code you see an MDX expression that returns a numeric value repeated across multiple calculations, you should consider abstracting it to its own calculated member; not only will this help performance, but it will improve the readability of your code. For example, take the following slow query which includes two calculated measures: WITH MEMBER [Measures].TEST1 AS [Measures].[Internet Sales Amount] / Count ( TopPercent ( { [Scenario].[Scenario].&[1] ,[Scenario].[Scenario].&[2] }* [Account].[Account].[Account].MEMBERS* [Date].[Date].[Date].MEMBERS ,10 ,[Measures].[Amount] ) )MEMBER [Measures].TEST2 AS [Measures].[Internet Tax Amount] / Count ( TopPercent ( { [Scenario].[Scenario].&[1] ,[Scenario].[Scenario].&[2] }* [Account].[Account].[Account].MEMBERS* [Date].[Date].[Date].MEMBERS* [Department].[Departments].[Department Level 02].MEMBERS ,10 ,[Measures].[Amount] ) )SELECT { [Measures].TEST1 ,[Measures].TEST2 } ON 0 ,[Customer].[Gender].[Gender].MEMBERS ON 1FROM [Adventure Works] A quick glance over the code shows that a large section of it occurs twice in both calculations—everything inside the Count function. If we remove that code to its own calculated member as follows: WITH MEMBER [Measures].Denominator AS Count ( TopPercent ( { [Scenario].[Scenario].&[1] ,[Scenario].[Scenario].&[2] }* [Account].[Account].[Account].MEMBERS* [Date].[Date].[Date].MEMBERS ,10 ,[Measures].[Amount] ) )MEMBER [Measures].TEST1 AS [Measures].[Internet Sales Amount] / [Measures].DenominatorMEMBER [Measures].TEST2 AS [Measures].[Internet Tax Amount] / [Measures].DenominatorSELECT { [Measures].TEST1 ,[Measures].TEST2 } ON 0 ,[Customer].[Gender].[Gender].MEMBERS ON 1FROM [Adventure Works] The query runs much faster, simply because instead of evaluating the count twice for each of the two visible calculated measures, we evaluate it once, cache the result in the calculated measure Denominator and then reference this in the other calculated measures. It's also possible to find situations where you can rewrite code to avoid evaluating a calculation that always returns the same result over different cells in the multidimensional space of the cube. This is much more difficult to do effectively though; the following blog entry describes how to do it in detail: http://tinyurl.com/fecache Tuning the implementation of MDX Like just about any other software product, Analysis Services is able to do some things more efficiently than others. It's possible to write the same query or calculation using the same algorithm but using different MDX functions and see a big difference in performance; as a result, we need to know which are the functions we should use and which ones we should avoid. Which ones are these though? Luckily MDX Studio includes functionality to analyse MDX code and flag up such problems—to do this you just need to click the Analyze button—and there's even an online version of MDX Studio that allows you to do this too, available at: http://mdx.mosha.com/. We recommend that you run any MDX code you write through this functionality and take its suggestions on board. Mosha walks through an example of using MDX Studio to optimise a calculation on his blog here: http://tinyurl.com/moshaprodvol Block computation versus cell-by-cellWhen the Formula Engine has to evaluate an MDX expression for a query it can basically do so in one of two ways. It can evaluate the expression for each cell returned by the query, one at a time, an evaluation mode known as "cell-by-cell"; or it can try to analyse the calculations required for the whole query and find situations where the same expression would need to be calculated for multiple cells and instead do it only once, an evaluation mode known variously as "block computation" or "bulk evaluation". Block computation is only possible in some situations, depending on how the code is written, but is often many times more efficient than cell-by-cell mode. As a result, we want to write MDX code in such a way that the Formula Engine can use block computation as much as possible, and when we talk about using efficient MDX functions or constructs then this is what we in fact mean. Given that different calculations in the same query, and different expressions within the same calculation, can be evaluated using block computation and cell-by-cell mode, it’s very difficult to know which mode is used when. Indeed in some cases Analysis Services can’t use block mode anyway, so it’s hard know whether we have written our MDX in the most efficient way possible. One of the few indicators we have is the Perfmon counter MDXTotal Cells Calculated, which basically returns the number of cells in a query that were calculated in cell-by-cell mode; if a change to your MDX increments this value by a smaller amount than before, and the query runs faster, you're doing something right. The list of rules that MDX Studio applies is too long to list here, and in any case it is liable to change in future service packs or versions; another good guide for Analysis Services 2008 best practices exists in the Books Online topic Performance Improvements for MDX in SQL Server 2008 Analysis Services, available online here: http://tinyurl.com/mdximp. However, there are a few general rules that are worth highlighting: Don't use the Non_Empty_Behavior calculation property in Analysis Services 2008, unless you really know how to set it and are sure that it will provide a performance benefit. It was widely misused with Analysis Services 2005 and most of the work that went into the Formula Engine for Analysis Services 2008 was to ensure that it wouldn't need to be set for most calculations. This is something that needs to be checked if you're migrating an Analysis Services 2005 cube to 2008. Never use late binding functions such as LookupCube, or StrToMember or StrToSet without the Constrained flag, inside calculations since they have a serious negative impact on performance. It's almost always possible to rewrite calculations so they don't need to be used; in fact, the only valid use for StrToMember or StrToSet in production code is when using MDX parameters. The LinkMember function suffers from a similar problem but is less easy to avoid using it. Use the NonEmpty function wherever possible; it can be much more efficient than using the Filter function or other methods. Never use NonEmptyCrossjoin either: it's deprecated, and everything you can do with it you can do more easily and reliably with NonEmpty. Lastly, don't assume that whatever worked best for Analysis Services 2000 or 2005 is still best practice for Analysis Services 2008. In general, you should always try to write the simplest MDX code possible initially, and then only change it when you find performance is unacceptable. Many of the tricks that existed to optimise common calculations for earlier versions now perform worse on Analysis Services 2008 than the straightforward approaches they were designed to replace. Caching We've already seen how Analysis Services can cache the values returned in the cells of a query, and how this can have a significant impact on the performance of a query. Both the Formula Engine and the Storage Engine can cache data, but may not be able to do so in all circumstances; similarly, although Analysis Services can share the contents of the cache between users there are several situations where it is unable to do so. Given that in most cubes there will be a lot of overlap in the data that users are querying, caching is a very important factor in the overall performance of the cube and as a result ensuring that as much caching as possible is taking place is a good idea. Formula cache scopes There are three different cache contexts within the Formula Engine, which relate to how long data can be stored within the cache and how that data can be shared between users: Query Context, which means that the results of calculations can only be cached for the lifetime of a single query and so cannot be reused by subsequent queries or by other users. Session Context, which means the results of calculations are cached for the lifetime of a session and can be reused by subsequent queries in the same session by the same user. Global Context, which means the results of calculations are cached until the cache has to be dropped because data in the cube has changed (usually when some form of processing takes place on the server). These cached values can be reused by subsequent queries run by other users as well as the user who ran the original query. Clearly the Global Context is the best from a performance point of view, followed by the Session Context and then the Query Context; Analysis Services will always try to use the Global Context wherever possible, but it is all too easy to accidentally write queries or calculations that force the use of the Session Context or the Query Context. Here's a list of the most important situations when that can happen: If you define any calculations (not including named sets) in the WITH clause of a query, even if you do not use them, then Analysis Services can only use the Query Context (see http://tinyurl.com/chrisfecache for more details). If you define session-scoped calculations but do not define calculations in the WITH clause, then the Session Context must be used. Using a subselect in a query will force the use of the Query Context (see http://tinyurl.com/chrissubfe). Use of the CREATE SUBCUBE statement will force the use of the Session Context. When a user connects to a cube using a role that uses cell security, then the Query Context will be used. When calculations are used that contain non-deterministic functions (functions which could return different results each time they are called), for example the Now() function that returns the system date and time, the Username() function or any Analysis Services stored procedure, then this forces the use of the Query Context. Other scenarios that restrict caching Apart from the restrictions imposed by cache context, there are other scenarios where caching is either turned off or restricted. When arbitrary-shaped sets are used in the WHERE clause of a query, no caching at all can take place in either the Storage Engine or the Formula Engine. An arbitrary-shaped set is a set of tuples that cannot be created by a crossjoin, for example: ({([Customer].[Country].&[Australia], [Product].[Category].&[1]),([Customer].[Country].&[Canada], [Product].[Category].&[3])}) If your users frequently run queries that use arbitrary-shaped sets then this can represent a very serious problem, and you should consider redesigning your cube to avoid it. The following blog entries discuss this problem in more detail: http://tinyurl.com/tkarbsethttp://tinyurl.com/chrisarbset Even within the Global Context, the presence of security can affect the extent to which cache can be shared between users. When dimension security is used the contents of the Formula Engine cache can only be shared between users who are members of roles which have the same permissions. Worse, the contents of the Formula Engine cache cannot be shared between users who are members of roles which use dynamic security at all, even if those users do in fact share the same permissions. Cache warming Since we can expect many of our queries to run instantaneously on a warm cache, and the majority at least to run faster on a warm cache than on a cold cache, it makes sense to preload the cache with data so that when users come to run their queries they will get warm-cache performance. There are two basic ways of doing this, running CREATE CACHE statements and automatically running batches of queries. Create Cache statement The CREATE CACHE statement allows you to load a specified subcube of data into the Storage Engine cache. Here's an example of what it looks like: CREATE CACHE FOR [Adventure Works] AS({[Measures].[Internet Sales Amount]}, [Customer].[Country].[Country].MEMBERS,[Date].[Calendar Year].[Calendar Year].MEMBERS) More detail on this statement can be found here: http://tinyurl.com/createcache CREATE CACHE statements can be added to the MDX Script of the cube so they execute every time the MDX Script is executed, although if the statements take a long time to execute (as they often do) then this might not be a good idea; they can also be run after processing has finished from an Integration Services package using an Execute SQL task or through ASCMD, and this is a much better option because it means you have much more control over when the statements actually execute—you wouldn't want them running every time you cleared the cache, for instance. Running batches of queries The main drawback of the CREATE CACHE statement is that it can only be used to populate the Storage Engine cache, and in many cases it's warming the Formula Engine cache that makes the biggest difference to query performance. The only way to do this is to find a way to automate the execution of large batches of MDX queries (potentially captured by running a Profiler trace while users go about their work) that return the results of calculations and so which will warm the Formula Engine cache. This automation can be done in a number of ways, for example by using the ASCMD command line utility which is part of the sample code for Analysis Services that Microsoft provides (available for download here: http://tinyurl.com/sqlprodsamples); another common option is to use an Integration Services package to run the queries, as described in the following blog entries— http://tinyurl.com/chriscachewarm and http://tinyurl.com/allancachewarm This approach is not without its own problems, though: it can be very difficult to make sure that the queries you're running return all the data you want to load into cache, and even when you have done that, user query patterns change over time so ongoing maintenance of the set of queries is important. Scale-up and scale-out Buying better or more hardware should be your last resort when trying to solve query performance problems: it's expensive and you need to be completely sure that it will indeed improve matters. Adding more memory will increase the space available for caching but nothing else; adding more or faster CPUs will lead to faster queries but you might be better off investing time in building more aggregations or tuning your MDX. Scaling up as much as your hardware budget allows is a good idea, but may have little impact on the performance of individual problem queries unless you badly under-specified your Analysis Services server in the first place. If your query performance degenerates as the number of concurrent users running queries increases, consider scaling-out by implementing what's known as an OLAP farm. This architecture is widely used in large implementations and involves multiple Analysis Services instances on different servers, and using network load balancing to distribute user queries between these servers. Each of these instances needs to have the same database on it and each of these databases must contain exactly the same data in it for queries to be answered consistently. This means that, as the number of concurrent users increases, you can easily add new servers to handle the increased query load. It also has the added advantage of removing a single point of failure, so if one Analysis Services server fails then the others take on its load automatically. Making sure that data is the same across all servers is a complex operation and you have a number of different options for doing this: you can either use the Analysis Services database synchronisation functionality, copy and paste the data from one location to another using a tool like Robocopy, or use the new Analysis Services 2008 shared scalable database functionality. The following white paper from the SQLCat team describes how the first two options can be used to implement a network load-balanced solution for Analysis Services 2005: http://tinyurl.com/ssasnlb. Shared scalable databases have a significant advantage over synchronisation and file-copying in that they don't need to involve any moving of files at all. They can be implemented using the same approach described in the white paper above, but instead of copying the databases between instances you process a database (attached in ReadWrite mode) on one server, detach it from there, and then attach it in ReadOnly mode to one or more user-facing servers for querying while the files themselves stay in one place. You do, however, have to ensure that your disk subsystem does not become a bottleneck as a result. Summary In this article we covered MDX calculation performance and caching, and also how to write MDX to ensure that the Formula Engine works as efficiently as possible. We've also seen how important caching is to overall query performance and what we need to do to ensure that we can cache data as often as possible, and we've discussed how to scale-out Analysis Services using network load balancing to handle large numbers of concurrent users.

Just recently, I found myself in a data migration project that served as an eye-opener. Our team had to migrate a customer system that utilized Act! and Peachtree. Both systems are not very famous for having good accessibility to their data. In fact, Peachtree is a non-SQL database that does not enforce data consistency. Act! also uses a proprietary table system that is based on a non-SQL database. The general migration logic was rather straightforward. However, our team found that the migration and consolidation of data into the new system posed multiple challenges, not only on the technical front, but also for the customer when it came to verifying the data. We used the on-the-edge tool xFusion Studio for data migration. This tool allows migrating and synchronizing data by using simple and advanced SQL data messaging techniques. The xFusion Studio tool has a graphical representation of how the data flows from the source to the target. When I looked at one section of this graphical representation, I started humming the song Welcome to the Jungle. Take a look at the following screenshot and find out why Guns and Roses may have provided the soundtrack for this data migration project: What we learned from the above screenshot is quite obvious and I have dedicated this article to helping you overcome these potential issues. Keep it simple and focus on information rather than data. You know that just by having more data does not always mean you’ve added more information. Sometimes, it just means a data jungle has been created. Making the right decisions at key milestones during the migration can keep the project simple and guarantee the success. Your goal should be to consolidate the islands of data into a more efficient and consistent database that provides real-time information. What you will learn about data migration In order to accomplish the task of migrating data from different sources into SAP Business ONE application, a strategy must be designed that addresses the individual needs of the project at hand. The data migration strategy uses proven processes and templates. The data migration itself can be managed as a mini project depending on the complexity. During the course of this article, the following key topics will be covered. The goal is to help you make crucial decisions, which will keep a project simple and manageable: Position the data migration tasks in the project plan – We will start by positioning the data migration tasks in the project plan. I will further define the required tasks that you need to complete as a part of the data migration. Data types and scenarios – With the general project plan structure in place, it is time to cover the common terms related to data migration. I will introduce you to the main aspects, such as master data and transactional data, as well as the impact they have on the complexity of data migration. SAP tools available for migration – During the course of our case study, I will introduce you to the data migration tools that come with SAP. However, there are also more advanced tools for complex migrations. You will learn about the main player in this area and how to use it. Process of migration – To avoid problems and guarantee success, the data migration project must follow a proven procedure. We will update the project plan to include the procedure and will also use the process during our case study. Making decisions about what data to bring – I mentioned that it is important to focus on information versus data. With the knowledge of the right tools and procedures, it is a good time to summarize the primary known issues and explain how to tackle them. The project plan We are still progressing in Phase 2 – Analysis and Design. The data migration is positioned in the Solution Architecture section and is called Review Data Conversion Needs (Amount and Type of Data). A thorough evaluation of the data conversion needs will also cover the next task in the project plan called Review Integration Points with any 3rd Party Solution. As you can see, the data migration task stands as a small task in the project plan. But as mentioned earlier, it can wind up being a large project depending on the number and size of data sources that need to be migrated. To honor this, we will add some more details to this task. As the task name suggests, we must review data conversion needs and identify the amount and type of data. This simple task must be structured in phases, just like the entire project that is structured in phases. Therefore, data migration needs to go through the following phases to be successful: 1. Design - Identify all of the Data Sources 2. Extraction of data into Excel or SQL for review and consistency 3. Review of Data and Verification(Via Customer Feedback) 4. Load into SAP System and Verification Note that the validation process and the consequential load could be iterative processes. For example, if the validated data has many issues, it only makes sense to perform a load into SAP if an additional verification takes place before the load. You only want to load data into an SAP system for testing if you know the quality of the records going to be loaded is good. Therefore, new phases were added in the project plan (seen below). Please do this in your project too based on the actual complexity and the number of data sources you have. A thorough look at the tasks above will be provided when we talk about the process of migration. Before we do that, the basic terms related to data migration will be covered. Data sources—where is my data There is a great variety in the potential types data sources. We will now identify the most common sources and explain their key characteristics. However, if there is a source that is not mentioned here, you can still migrate the data easily by transitioning it into one of the following formats. Microsoft Excel and text data migration The most common format for data migration is Excel, or text-based files. Text-based files are formatted using commas or tabs as field separators. When a comma is used as a field separator, the file format is referred to as Comma Separated Values (CSV). Most of the migration templates and strategies are based on Excel files that have specific columns where you can manually enter data, or copy and paste larger chunks. Therefore, if there is any way for you to extract data from your current system and present it in Excel, you have already done a great deal of data migration work. Microsoft Access An Access database is essentially an Excel sheet on a larger scale with added data consistency capability. It is a good idea to consider extracting Access tables to Excel in order to prepare for data migration. SQL If you have very large sets of data, then instead of using Excel, we usually employ an SQL database. The database then has a set of tables instead of Excel sheets. Using SQL tables, we can create SQL statements that can verify data and analyze results sets. Please note that you can use any SQL database, such as Microsoft SQL Server, Oracle, IBM DB, and so on. SaaS (Netsuite, Salesforce) SaaS stands for Software as a Service. Essentially, it means you can use software functionality based on a subscription. However, you don't own the solution. All of the hardware and software is installed at the service center, so you don't need to worry about hardware and software maintenance. However, keep in mind that these services don't allow you to manage the service packs according to your requirements. You need to adjust your business to the schedule of the SaaS company. If you are migrating from a modern SaaS solution, such as Salesforce or Netsuite, you will probably know that the data is not at your site, but rather stored at your solution hosting provider. Getting the data out to migrate to another solution may be done by obtaining reports, which could then be saved in an Excel format. Other legacy data The term legacy data is often mentioned when evaluating larger old systems. Legacy data basically comprises a large set of data that a company is using on mostly obsolete systems. AS/400 or Mainframe The IBM AS/400 is a good example of a legacy data source. Experts who are capable of extracting data from these systems are highly sought after, and so the budget must be on a higher scale. AS/400 data can often be extracted into a text or an Excel format. However, the data may come without headings. The headings are usually documented in a file that describes the data. You need to make sure that you get the file definitions, without which the pure text files may be meaningless. In addition, the media format is worth considering. An older AS/400 system may utilize a backup tape format which is not available on your Intel server. Peachtree, QuickBooks, and Act! Another potential source for data migration may be a smaller PC-based system, such as Peachtree, QuickBooks, or Act!. These systems have a different data format, and are based on non-SQL databases. This means the data cannot be accessed via SQL. In order to extract data from those systems, the proprietary API must be used. For example, if Peachtree displays data in the applications forms, it uses the program logic to put the pieces together from different text files. Getting data out from these types of systems is difficult and sometimes impossible. It is recommended to employ the relevant API to access the data in a structured way. You may want to run reports and export the results to text or Excel. Data classification in SAP Business ONE There are two main groups of data that we will migrate to the SAP Business ONE application: master data and transaction data. Master data Master data is the basic information that SAP Business ONE uses to record transactions (for example, business partner information). In addition, information about your products, such as items, finished goods, and raw materials are considered master data. Master data should always be migrated if possible. It can easily be verified and structured in an Excel or SQL format. For example, the data could be displayed using Excel sheets. You can then quickly verify that the data is showing up in the correct columns. In addition, you can see if the data is broken down into its required components. For example, each Excel column should represent a target field in SAP Business ONE. You should avoid having a single column in Excel that provides data for more than one target in SAP Business ONE. Transaction data Transaction data are proposals, orders, invoices, deliveries, and other similar information that comprise a combination of master data to create a unique business document. Customers often will want to migrate historical transactions from older systems. However, the consequences of doing this may have a landslide effect. For example, inventory is valuated based on specific settings in the finance section of a system. If these settings are not identical in the new system, transactions may look different in the old and the new system. This makes the migration very risky as the data verification becomes difficult on the customer side. I recommend making historical transactions available via a reporting database. For example, often, sales history must be available when migrating data. You can create a reporting database that provides sales history information. The user can use this data via reports within the SAP Business ONE application. Therefore, closed transactions should be migrated via a reporting database . Closed transactions are all of the business-related activities that were fully completed in the old system. Open transactions, on the other hand, are all of the business-related activities that are currently not completed. It makes sense that the open transactions be migrated directly to SAP, and not to a history database because they will be completed within the new SAP system. As a result of the data migration, you would be able to access sales history information from within SAP by accessing a reporting database. Open transactions will be completed within SAP, and then consequently lead to new transactions in SAP. Create a history database for sales history and manually enter open transactions. SAP DI-API Now that we know the main data types for an SAP migration, and the most common sources, we can take a brief look at the way the data is inserted into the SAP system. Based on the SAP guidelines, you are not allowed to insert data directly in the underlying SQL tables. The reason for that is that it can cause inconsistencies. When SAP works with the database, multiple tables are often updated. If you manually update a table to insert data, there is a good chance that another table has a link that also requires updating. Therefore, unless you know the exact table structure for the data you are trying to update, don't mess with the SAP SQL tables. If you carefully read this and understand the table structure, you will now know that there may be situations where you decide to access the tables directly. If you decide to insert data directly into the SAP database tables, you run the risk of losing your warranty. Migration scenarios and key decisions Data migration not only takes place as a part of a new SAP implementation, but also if you have a running system and you want to import leads or a list of new items. Therefore, it is a good idea to learn about the scenarios that you may come across and be able to select the right migration and integration tools. As outlined before, data can be divided into two groups: master data and transaction data. It is important that you separate the two, and structure each data migration accordingly. Master data is an essential component for manifesting transactions. Therefore, even if you need to bring over transactional data, the master data must already be in place. Always start with the master data alongside a verification procedure, and then continue with the relevant transaction data. Let’s now briefly look at the most common situations where you may require the evaluation of potential data migration options. New company (start-up) In this setup, you may not have extensive amounts of existing data to migrate. However, you may want to bring over lead lists or lists of items. During the course of this article, we will import a list of leads into SAP using the Excel Import functionality. Many new companies require the capability to easily import data into SAP. As you already know by now, the import of leads and item information will be considered as importing master data. Working with this master data by entering sales orders and so forth, would constitute transaction data. Transaction data is considered closed if all of the relevant actions are performed. For example, a sales order is considered closed if the items are delivered, invoiced, and paid for. If the chain of events is not complete, the transaction is open. Islands of data scenario This is the classic situation for an SAP implementation. You will first need to identify the available data sources and their formats. Then, you select the master data you want to bring over. With multiple islands of data, an SAP master record may result from more than one source. A business partner record may come, in part, from an existing accounting system, such as QuickBooks or Peachtree. Whereas other parts may come from a CRM system, such as Act!. For example, the billing information may be retrieved from the finance system and the relevant lead and sales information, such as specific contacts and notes, may come from the CRM system. In such a case, you need to merge this information into a new consistent master record in SAP. For this situation, first manually put the pieces together. Once the manual process works, you can attempt to automate the process. Don't try to directly import all of the data. You should always establish an intermediary level that allows for data verification. Only then import the data into SAP. For example, if you have QuickBooks and Act!, first merge the information into Excel for verification, and then import it into SAP. If the amount of data is large, you can also establish an SQL database. In that case, the Excel sheets would be replaced by SQL tables. IBM legacy data migration The migration of IBM legacy data is potentially the most challenging because the IBM systems are not directly compatible with Windows-based systems. Therefore, almost naturally, you will establish a text-based, or an Excel-formatted, representation of the IBM data. You can then proceed with verifying the information. SQL migration The easiest migration type is obviously the one where all of the data is already structured and consistent. However, you will not always have documentation of the table structure where the data resides. In this case, you need to create queries against the SQL tables to verify the data. The queries can then be saved as views. The views you create should always represent a consistent set of information that you can migrate. For example, if you have one table with address information, and another table with customer ID fields, you can create a view that consolidates this information into a single consistent set. Process of migration for your project I briefly touched upon the most common data migration scenarios so you can get a feel for the process. As you can see, whatever the source of data is, we always attempt to create an intermediary platform that allows the data to be verified. This intermediary platform is most commonly Excel or an SQL database. The process of data migration has the following subtasks: Identify available data sources Structure data into master data and transaction data Establish an intermediary platform with Excel or SQL Verify data Match data columns with Excel templates Run migration based on templates and verify data Based on this procedure, I have added more detail to the project plan. As you can see in this example, based on the required level of detail, we can make adjustments to the project plan to address the requirements: SAP standard import features Let's take a look at the available data exchange features in SAP. SAP provides two main tools for data migration. The fi rst option is to use the available menu in the SAP Business ONE client interface to exchange data. The other option is to use the Data Transfer Workbench (DTW). Standard import/export features— walk-through You can reach the Import from Excel form via Administration | Data Import/Export. As you can see in the following screenshot on the right top section of the form, the type of import is a drop-down selection. The options are BP and Items. In the screenshot, we have selected BP, which allows business partner information to be imported. There are drop-down fields that you can select based on the data you want to import. However, keep in mind that certain fields are mandatory, such as the BP Code field, whereas others are optional. The fields you select are associated with a column as you can see here: If you want to find out if a field is mandatory or not, simply open SAP and attempt to enter the data directly in the relevant SAP form. For example, if you are trying to import business partner information, enter the fields you want to import and see if the record can be saved. If you are missing any mandatory fields, SAP will provide an error message. You can modify the data that you are planning to import based on that. When you click on the OK button in the Import from Excel form (seen above), the Excel sheet with all of the data needs to be selected. In the following screenshot, you can see how the Excel sheet in our example looks. For example, column A has all of the BP Codes. This is in line with the mapping of columns to fields that we can see on the Import from Excel form. Please note that the file we select must be in a .txt format. For this example, I used the Save As feature in Excel (seen in the following screenshot) to save the file in the Text MS-DOS (*.txt) format. I was then able to select the BP Migration.txt file. This is actually a good thing because it points to the fact that you can use any application that can save data in the .txt format as the data source. The following screenshot shows the Save As screen: I imported the file and a success message confirms that the records were imported into SAP: A subsequent check in SAP confirms that the BP records that I had in the text file are now available in SAP: In the example, we only used two records. It is recommended to start out with a limited number of records to verify that the import is working. Therefore, you may start by reducing your import file to five records. This has the advantage of the import not taking a long time and you can immediately verify the result. See the following screenshot: Sometimes, it is not clear what kind of information SAP expects when importing. For example, at first Lead, Customer, Vendor were used in Column C to indicate the type of BP that was to be imported. However, this resulted in an error message upon completion of the import. Therefore, system information was activated to check what information SAP requires for the BP Type representation. As you can see in the screenshot of the Excel sheet you get when you click on the OK button in the Import from Excel form, the BP Type information is indicated by only one letter using L, C, or V. In the example screenshot above, you can clearly see L in the lower left section. The same thing is done for Country in the Addresses section. You can try that by navigating to Administration | Sales | Countries, and then hovering over the country you will be importing. In my example, USA was internally represented by SAP as US. It is a minor issue. However, when importing data, all of these issues need to be addressed. Please note that the file you are trying to import should not be open in Excel at the same time, as this may trigger an error. The Excel or text file does not have a header with a description of the data. Standard import/export features for your own project SAP’s standard import functionality for business partners and items is very straightforward. For your own project, you can prepare an Excel sheet for business partners and items. If you need to import BP or item information from another system, you can get this done quickly. If you get an error during the import process, try to manually enter the data in SAP. In addition, you can use the System Information feature to identify how SAP stores information in the database. I recommend you first create an Excel sheet with a maximum of two records to see if the basic information and data format is correct. Once you have this running, you can add all of the data you want to import. Overall, this functionality is a quick way to get your own data into the system. This feature can also be used in case you regularly receive address information. For example, if you have salespeople visiting trade fairs, you can provide them with the Excel sheet that you may have prepared for BP import. The salespeople can directly add their information there. Once they return from the trade fair with the Excel fi les, you can easily import the information into SAP and schedule follow-up activities using the Opportunity Management System. The item import is useful if you work with a vendor who updates his or her price lists and item information on a monthly basis. You can prepare an Excel template where the item information will regularly be entered and you can easily import the updates into SAP. Data Migration Workbench (DTW) The SAP standard import/export features are straightforward, but may not address the full complexity of the data that you need to import. For this situation, you may want to evaluate the SAP Data Migration Workbench (DTW). The functionality of this tool provides a greater level of detail to address the potential data structures that you want to import. To understand the basic concept of the DTW, it is a good idea to look at the different master data sections in SAP as business objects. A business object groups related information together. For example, BP information can have much more detail than what was previously shown in the standard import. The DTW templates and business objects To better understand the business object metaphor, you need to navigate to the DTW directory and evaluate the Templates folder. The templates are organized by business objects. The oBusinessPartners business object is represented by the folder with the same name (seen below). In this folder, you can find Excel template files that can be used to provide information for this type of business object. The following objects are available as Excel templates: BPAccountReceivables BPAddresses BPBankAccounts BPPaymentDates BPPaymentMethods BPWithholdingTax BusinessPartners ContactEmployees Please notice that these templates are Excel .xlt files, which is the Excel template extension. It is a good idea to browse through the list of templates and see the relevant templates. In a nutshell, you essentially add your own data to the templates and use DTW to import the data. Connecting to DTW In order to work with DTW, you need to connect to your SAP system using the DTW interface. The following screenshot shows the parameters I used to connect to the Lemonade Stand database: Once you are connected, a wizard-type interface walks you through the required steps to get started. Look at the next screenshot: The DTW examples and templates There is also an example folder in the DTW installation location on your system. This example folder has information about how to add information to your Excel templates. The following screenshot shows an example for business partner migration. You can see that the Excel template does have a header line on top that explains the content in the particular column. The actual template files also have comments in the header fi le, which provide information about the data format expected, such as String, Date, and so on. See the example in this screenshot: The actual template is empty and you need to add your information as shown here:   DTW for your own project If you realize that the basic import features in SAP are not sufficient, and your requirements are more challenging, evaluate DTW. Think of the data you want to import as business objects where information is logically grouped. If you are able to group your data together, you can modify the Excel templates with your own information. The DTW example folder provides working examples that you can use to get started. Please note that you should establish a test database before you start importing data this way. This is because once new data arrives in SAP, you need to verify the results based on the procedure discussed earlier. In addition, be prepared to fine-tune the import. Often, an import and data verification process takes four attempts of data importing and verification. Summary In this article, we covered the tasks related to data migration. This also included some practical examples for simple data imports related to business partner information and items. In addition, more advanced topics were covered by introducing the SAP DTW (Data Transfer Workbench) and the related aspects to get you started. During the course of this article, we positioned the data migration task in the project plan. The project plan was then fine-tuned with more detail to give some justice to the potential complexity of a data migration project. The data migration tasks established a process, from design to data mapping and verification of the data. Notably, the establishment of an intermediary data platform was recommended for your projects. This will help you verify data at each step of the migration. The key message of keeping it simple will be the basis for every migration project. The data verification task ensures simplicity and the quality of your data. If you have read this article you may be interested to view : Competitive Service and Contract Management in SAP Business ONE Implementation: Part 1 Competitive Service and Contract Management in SAP Business ONE Implementation: Part 2 Data Migration Scenarios in SAP Business ONE Application- part 2

JClic (http://clic.xtec.net/en) is a free (under a GPL license) software application released by the Ministry of Education of the Government of Catalunya. It is written in Java, and allows us to create the following seven types of interactive activities: Association games - to identify the relationship between two groups of data Memory games - to discover hidden pairs of elements Exploring, Identifying, and Information games - to start with initial information and choose paths to the answer Puzzles – to order graphics, text, and audio, or to combine graphics and audio Written answers – to write text, a word, or a sentence Text activities – to solve exercises based on words, sentences, letters, and paragraphs (these can be completed, corrected, or ordered) Wordsearches and crosswords – to find hidden words or solve crossword puzzles JClic exercises can be more visually appealing than Hot Potatoes, as we will see, and can be particularly useful for younger students. But, as they require Java, this should be checked with the ICT coordinator as Java must be installed on the schools' PCs. In the software download area (http://clic.edu365.cat/en/jclic/download.htm), we can download JClic author, the application that allows us to create these activities. The file will use WebStart, and will run from a single file, named jclic.jnlp. When we run it for the first time, in Microsoft Vista at least, we will need to give permission for the application to Run (selecting the Always trust content from this publisher option will avoid having to perform this step every time we start JClic): Then JClic will start loading: The interface of JClic author is as shown in the following screenshot: As it can be seen, there are four available tabs: Project – the default tab, which allows us to define some details of the project. Media library – where pictures and other multimedia are managed. Activities – where the project activities are created or modified. This tab further contains four tabs. Sequences – where we can sequence several activities in the same project. The options inside these tabs will be available only after we create a new project. Start a new project The first step in building interactive JClic activities is to start a new project (via menu option File | New project): We should then define: The name of the project The name of the file in which the project will be saved (having a double extension of .jclic.zip) The default folder for saving the files to is:C:/Programme Files/JClic/projects/name of project (in Windows)$home/JClic/projects/name of project (in other OSs) We can change this and, if we are using multimedia files, again we should keep everything organized inside this folder. Creating a puzzle activity We are now ready to start creating our first activity, a puzzle. In Module 2 - A world of music—we can pick some of the pictures of instruments that our students gathered in the Instrument Mappers activities and create a jigsaw puzzle as part of a final game for the module. We will perform the following steps: Provide details of the project in the Project tab. Import a picture to the Media library. Add an activity called Exchangeable puzzle. Create a sequence. Note that we are starting from the tab on the left and moving to the right as we configure the activity. As an example, I created a project called Instruments: Next, I added a description of the activity and specified myself as an author by clicking on the plus (+) button. We can specify in more details, but for now this much information is enough as an example. Now, let's import a picture into our Media library by clicking on the icon on the far left on the toolbar: If we pick a picture from any folder on our computer, JClic will recommend that this be copied to the project folder (we should accept this recommendation, especially if we want to upload our activity to Moodle). Note that the Media library accepts different kinds of multimedia files, from MP3 to Flash and video. This can be useful in other types of activities. We now have a picture of a lamelaphone that will make a difficult jigsaw for our students. Lamelaphone image source: Weeks, Alex (2006). Mbira dzavadzimu 1.jpg. Retrieved October 12, 2008,from http://commons.wikimedia.org/wiki/File:Mbira_dzavadzimu_1.jpg The next step is to add the puzzle activity, on the Activities tab, by clicking on the icon on the far left of the toolbar: A dialog box is displayed, and in this menu we should select the Exchange puzzle option, entering a name for our puzzle, in the input field at the bottom of the dialog box: We can then add a description of the activity, and if needed, we can define a timer countdown (in the Counters section), among other options: Reports are mentioned in this dialog box. JClic provides a way to gather students' responses, but due to the complexity of this functionality, we will not deal with it in this book. In the Window tab, on the the Activities tab, we can also define some color options, as shown in the screenshot below: In the Messages tab, we can add an initial message, which for example, gives the context of the activity, and a final message, as feedback for the exercise by clicking on the dark gray areas: Finally, in the Panel tab, we should insert the lamelaphone picture from our Media library and define the kind of jigsaw that we want. In the following screenshot, I have done the following three things: Selected a jigsaw with curved unions. Defined 5x5 pieces. Selected the image from the Media library. Our puzzle activity is now ready, and we can now add a finding pairs activity to the same project, in a sequence.

Within the past five years, there has been a major change in the type of content found on the World Wide Web. In just a few short years, content has evolved from being primarily text and images, into a multimedia experience! Drupal contributors have put much effort in making this integration with multimedia as easy as possible. However, one issue still remains: in order to present multimedia to your users, you cannot rely on Drupal alone. You must have another application layer to present that media. This is most typically a Flash application that allows the user to listen or watch that media from within their web browser. This article explores how to use Drupal to manage a list of audio nodes and also builds a Flash application to play that music. When it comes to multimedia, Flash is the portal of choice for playing audio on a web sites. Integrating audio in Drupal is surprisingly easy, thanks to the contribution of the Audio module. This module allows you to upload audio tracks to your Drupal website (typically in MP3 format), by creating an Audio node. It also comes with a very basic audio player that will play those audio tracks in the node that was created. To start, let's download and enable the Audio module along with the Token, Views, and getID3 modules, which are required for the Audio module. The modules that you will need to download and install are as follows: Audio—http://www.drupal.org/project/audio Views—http://www.drupal.org/project/views Token—http://www.drupal.org/project/token getID3—http://www.drupal.org/project/getid3 At the time of writing this article, the Audio module was still considered "unstable". Because of this, I would recommend downloading the development version until a stable release has been made. It is also recommended to use the development or "unstable" versions for testing purposes only. Once we have downloaded these modules and placed them in our site's modules folder, we can enable the Audio module by first navigating to the Administer | Modules section, and then enabling the checkboxes in the Audio group as follows: After you have enabled these modules, you will probably notice an error at the top of the Administrator section that says the following: This error is shown because we have not yet installed the necessary PHP library to extract the ID3 information from our audio files. The ID3 information is the track information that is embedded within each audio file, and can save us a lot of time from having to manually provide that information when attaching each audio file to our Audio nodes. So, our next step will be to install the getID3 library so that we can utilize this great feature. Installing the getID3 library The getID3 library is a very useful PHP library that will automatically extract audio information (called ID3) from any given audio track. We can install this useful utility by going to http://sourceforge.net/project/showfiles.php?group_id=55859, which is the getID3 library URL at SourceForge.net. Once we have done this, we should see the following: We can download this library by clicking on the Download link on the first row, which is the main release. This will then take us to a new page, where we can download the ZIP package for the latest release. We can download this package by clicking on the latest ZIP link, which at the time of writing this article was getid3-1.7.9.zip Once this package has finished downloading, we then need to make sure that we place the extracted library on the server where the getID3 module can use it. The default location for the getID3 module, for this library, is within our site's modules/getid3 directory. Within this directory, we will need to create another directory called getid3, and then place the getid3 directory from the downloaded package into this directory. To verify that we have installed the library correctly, we should have the getid3.php at the following location: Our next task is to remove the demos folder from within the getid3 library, so that we do not present any unnecessary security holes in our system. Once this library is in the correct spot, and the demos folder has been removed, we can refresh our Drupal Administrator section and see that the error has disappeared. If it hasn't, then verify that your getID3 library is in the correct location and try again. Now that we have the getID3 library installed, we are ready to set up the Audio content type. Setting up the Audio content type When we installed the Audio module, it automatically created an Audio content type that we can now use to add audio to our Drupal web site. But before we add any audio to our web site, let's take a few minutes to set up the Audio content type to the way we want it. We will do so by navigating to Administer | Content Types, and then clicking on the edit link, next to the Audio content type. Our goal here is to set up the Audio content type so that the default fields make sense to the Audio content type. Drupal adds the Body field to all new content types, which doesn't make much sense when creating an Audio content. We can easily change this by simply expanding the Submission form settings. We can then replace the Body label with Description, since it is easily understood when adding new Audio tracks to our system. We will save this content type by clicking on the Save content type button at the bottom of the page. Now, we are ready to start adding audio content to our Drupal web site. Creating an Audio node We will add audio content by going to Create Content, and then clicking on Audio, where we should then see the following on the page: You will probably notice that the Title of this form has already been filled out with some strange looking text (as shown in the previous screenshot). This text is a series of tags, which are used to represent track information that is extracted using the getID3 module that we installed earlier. Once this ID3 information is extracted, these tags will be replaced with the Title and Artist of that track, and then combined to form the title of this node. This will save a lot of time because we do not have to manually provide this information when submitting a new audio track to our site. We can now upload any audio track by clicking on the Browse button next to the Add a new audio file field. After it adds the file to the field, we can submit this audio track to Drupal by clicking on the Save button at the bottom of the page, which will then show you something like the following screenshot: After this node has been added, you will notice that there is a player already provided to play the audio track. Although this player is really cool, there are some key differences between the player provided by the Audio module and the player that we will create later in this article. How our player will be different (and better) The main difference between the player that is provided by the Audio module and the player that we are getting ready to build is how it determines which file to play. In the default player, it uses flash variables passed to the player to determine which file to play. This type of player-web site interaction places the burden on Drupal to provide the file that needs to be played. In a way, the default player is passive, where it does nothing unless someone tells it to do something. The player that we will be building is different because instead of Drupal telling our player what to play, we will take an active approach and query Drupal for the file we wish to play. This has several benefits, such as that the file path does not have to be exposed to the public in order for it to be played. So, let's create our custom player!

Implementing Tables and Lists The first actual sample is very common in applications: tables and lists. In this sample, the table is populated using the DWR utility functions, and a remoted Java class. The sample code also shows how DWR is used to do inline table editing. When a table cell is double-clicked, an edit box opens, and it is used to save new cell data. The sample will have country data in a CSV file: country Name, Long Name, two-letter Code, Capital, and user-defined Notes. The user interface for the table sample appears as shown in the following screenshot: Server Code for Tables and Lists The first thing to do is to get the country data. Country data is in a CSV file (named countries.csv and located in the samples Java package). The following is an excerpt of the content of the CSV file (data is from http://www.state.gov ). Short-form name,Long-form name,FIPS Code,CapitalAfghanistan,Islamic Republic of Afghanistan,AF,KabulAlbania,Republic of Albania,AL,TiranaAlgeria,People's Democratic Republic of Algeria,AG,AlgiersAndorra,Principality of Andorra,AN,Andorra la VellaAngola,Republic of Angola,AO,LuandaAntigua andBarbuda,(no long-form name),AC,Saint John'sArgentina,Argentine Republic,AR,Buenos AiresArmenia,Republic of Armenia,AM,Yerevan The CSV file is read each time a client requests country data. Although this is not very efficient, it is good enough here. Other alternatives include an in-memory cache or a real database such as Apache Derby or IBM DB2. As an example, we have created a CountryDB class that is used to read and write the country CSV. We also have another class, DBUtils, which has some helper methods. The DBUtils code is as follows: package samples;import java.io.BufferedReader;import java.io.File;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.PrintWriter;import java.util.List;import java.util.Vector;public class DBUtils { private String fileName=null; public void initFileDB(String fileName) { this.fileName=fileName; // copy csv file to bin-directory, for easy // file access File countriesFile = new File(fileName); if (!countriesFile.exists()) { try { List<String> countries = getCSVStrings(null); PrintWriter pw; pw = new PrintWriter(new FileWriter(countriesFile)); for (String country : countries) { pw.println(country); } pw.close(); } catch (IOException e) { e.printStackTrace(); } } } protected List<String> getCSVStrings(String letter) { List<String> csvData = new Vector<String>(); try { File csvFile = new File(fileName); BufferedReader br = null; if(csvFile.exists()) { br=new BufferedReader(new FileReader(csvFile)); } else { InputStream is = this.getClass().getClassLoader() .getResourceAsStream("samples/"+fileName); br=new BufferedReader(new InputStreamReader(is)); br.readLine(); } for (String line = br.readLine(); line != null; line = br.readLine()) { if (letter == null || (letter != null && line.startsWith(letter))) { csvData.add(line); } } br.close(); } catch (IOException ioe) { ioe.printStackTrace(); } return csvData; }} The DBUtils class is a straightforward utility class that returns CSV content as a List of Strings. It also copies the original CSV file to the runtime directory of any application server we might be running. This may not be the best practice, but it makes it easier to manipulate the CSV file, and we always have the original CSV file untouched if and when we need to go back to the original version. The code for CountryDB is given here: package samples;import java.io.FileWriter;import java.io.IOException;import java.io.PrintWriter;import java.util.Arrays;import java.util.List;import java.util.Vector;public class CountryDB { private DBUtils dbUtils = new DBUtils(); private String fileName = "countries.csv"; public CountryDB() { dbUtils.initFileDB(fileName); } public String[] getCountryData(String ccode) { List<String> countries = dbUtils.getCSVStrings(null); for (String country : countries) { if (country.indexOf("," + ccode + ",") > -1) { return country.split(","); } } return new String[0]; } public List<List<String>> getCountries(String startLetter) { List<List<String>> allCountryData = new Vector<List<String>>(); List<String> countryData = dbUtils.getCSVStrings(startLetter); for (String country : countryData) { String[] data = country.split(","); allCountryData.add(Arrays.asList(data)); } return allCountryData; } public String[] saveCountryNotes(String ccode, String notes) { List<String> countries = dbUtils.getCSVStrings(null); try { PrintWriter pw = new PrintWriter(new FileWriter(fileName)); for (String country : countries) { if (country.indexOf("," + ccode + ",") > -1) { if (country.split(",").length == 4) { // no existing notes country = country + "," + notes; } else { if (notes.length() == 0) { country = country.substring(0, country .lastIndexOf(",")); } else { country = country.substring(0, country .lastIndexOf(",")) + "," + notes; } } } pw.println(country); } pw.close(); } catch (IOException ioe) { ioe.printStackTrace(); } String[] rv = new String[2]; rv[0] = ccode; rv[1] = notes; return rv; }} The CountryDB class is a remoted class. The getCountryData() method returns country data as an array of strings based on the country code. The getCountries() method returns all the countries that start with the specified parameter, and saveCountryNotes() saves user added notes to the country specified by the country code. In order to use CountryDB, the following script element must be added to the index.jsp file together with other JavaScript elements. <script type='text/javascript' src='/DWREasyAjax/dwr/interface/CountryDB.js'></script> There is one other Java class that we need to create and remote. That is the AppContent class that was already present in the JavaScript functions of the home page. The AppContent class is responsible for reading the content of the HTML file and parses the possible JavaScript function out of it, so it can become usable by the existing JavaScript functions in index.jsp file. package samples;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.io.InputStream;import java.util.List;import java.util.Vector;public class AppContent { public AppContent() { } public List<String> getContent(String contentId) { InputStream is = this.getClass().getClassLoader().getResourceAsStream( "samples/"+contentId+".html"); String content=streamToString(is); List<String> contentList=new Vector<String>(); //Javascript within script tag will be extracted and sent separately to client for(String script=getScript(content);!script.equals("");script=getScript(content)) { contentList.add(script); content=removeScript(content); } //content list will have all the javascript //functions, last element is executed last //and all other before html content if(contentList.size()>1) { contentList.add(contentList.size()-1, content); } else { contentList.add(content); } return contentList; } public List<String> getLetters() { List<String> letters=new Vector<String>(); char[] l=new char[1]; for(int i=65;i<91;i++) { l[0]=(char)i; letters.add(new String(l)); } return letters; } public String removeScript(String html) { //removes first script element int sIndex=html.toLowerCase().indexOf("<script "); if(sIndex==-1) { return html; } int eIndex=html.toLowerCase().indexOf("</script>")+9; return html.substring(0, sIndex)+html.substring(eIndex); } public String getScript(String html) { //returns first script element int sIndex=html.toLowerCase().indexOf("<script "); if(sIndex==-1) { return ""; } int eIndex=html.toLowerCase().indexOf("</script>")+9; return html.substring(sIndex, eIndex); } public String streamToString(InputStream is) { String content=""; try { ByteArrayOutputStream baos=new ByteArrayOutputStream(); for(int b=is.read();b!=-1;b=is.read()) { baos.write(b); } content=baos.toString(); } catch(IOException ioe) { content=ioe.toString(); } return content; }} The getContent() method reads the HTML code from a file based on the contentId. ContentId was specified in the dwrapplication.properties file, and the HTML is just contentId plus the extension .html in the package directory. There is also a getLetters() method that simply lists letters from A to Z and returns a list of letters to the browser. If we test the application now, we will get an error as shown in the following screenshot: We know why the AppContent is not defined error occurs, so let's fix it by adding AppContent to the allow element in the dwr.xml file. We also add CountryDB to the allow element. The first thing we do is to add required elements to the dwr.xml file. We add the following creators within the allow element in the dwr.xml file. <create creator="new" javascript="AppContent"> <param name="class" value="samples.AppContent" /> <include method="getContent" /> <include method="getLetters" /> </create> <create creator="new" javascript="CountryDB"> <param name="class" value="samples.CountryDB" /> <include method="getCountries" /> <include method="saveCountryNotes" /> <include method="getCountryData" /></create> We explicitly define the methods we are remoting using the include elements. This is a good practice, as we don't accidentally allow access to any methods that are not meant to be remoted. Client Code for Tables and Lists We also need to add a JavaScript interface to the index.jsp page. Add the following with the rest of the scripts in the index.jsp file. <script type='text/javascript' src='/DWREasyAjax/dwr/interface/AppContent.js'></script> Before testing, we need the sample HTML for the content area. The following HTML is in the TablesAndLists.html file under the samples directory: <h3>Countries</h3><p>Show countries starting with <select id="letters" onchange="selectLetter(this);return false;"> </select><br/>Doubleclick "Notes"-cell to add notes to country.</p><table border="1"> <thead> <tr> <th>Name</th> <th>Long name</th> <th>Code</th> <th>Capital</th> <th>Notes</th> </tr> </thead> <tbody id="countryData"> </tbody></table><script type='text/javascript'>//TO BE EVALEDAppContent.getLetters(addLetters);</script> The script element at the end is extracted by our Java class, and it is then evaluated by the browser when the client-side JavaScript receives the HTML. There is the select element, and its onchange event calls the selectLetter() JavaScript function. We will implement the selectLetter() function shortly. JavaScript functions are added in the index.jsp file, and within the head element. Functions could be in separate JavaScript files, but the embedded script is just fine here. function selectLetter(selectElement){ var selectedIndex = selectElement.selectedIndex; var selectedLetter= selectElement.options[selectedIndex ].value; CountryDB.getCountries(selectedLetter,setCountryRows);}function addLetters(letters){dwr.util.addOptions('letters',['letter...']);dwr.util.addOptions('letters',letters);}function setCountryRows(countryData){var cellFuncs = [ function(data) { return data[0]; }, function(data) { return data[1]; }, function(data) { return data[2]; }, function(data) { return data[3]; }, function(data) { return data[4]; }];dwr.util.removeAllRows('countryData');dwr.util.addRows( 'countryData',countryData,cellFuncs, { cellCreator:function(options) { var td = document.createElement("td"); if(options.cellNum==4) { var notes=options.rowData[4]; if(notes==undefined) { notes='&nbsp;';// + options.rowData[2]+'notes'; } var ccode=options.rowData[2]; var divId=ccode+'_Notes'; var tdId=divId+'Cell'; td.setAttribute('id',tdId); var html=getNotesHtml(ccode,notes); td.innerHTML=html; options.data=html; } return td; }, escapeHtml:false });}function getNotesHtml(ccode,notes){ var divId=ccode+'_Notes'; return "<div onDblClick="editCountryNotes('"+divId+"','"+ccode+"');" id=""+divId+"">"+notes+"</div>";}function editCountryNotes(id,ccode){ var notesElement=dwr.util.byId(id); var tdId=id+'Cell'; var notes=notesElement.innerHTML; if(notes=='&nbsp;') { notes=''; } var editBox='<input id="'+ccode+'NotesEditBox" type="text" value="'+notes+'"/><br/>'; editBox+="<input type='button' id='"+ccode+"SaveNotesButton' value='Save' onclick='saveCountryNotes(""+ccode+"");'/>"; editBox+="<input type='button' id='"+ccode+"CancelNotesButton' value='Cancel' onclick='cancelEditNotes(""+ccode+"");'/>"; tdElement=dwr.util.byId(tdId); tdElement.innerHTML=editBox; dwr.util.byId(ccode+'NotesEditBox').focus();}function cancelEditNotes(ccode){ var countryData=CountryDB.getCountryData(ccode, { callback:function(data) { var notes=data[4]; if(notes==undefined) { notes='&nbsp;'; } var html=getNotesHtml(ccode,notes); var tdId=ccode+'_NotesCell'; var td=dwr.util.byId(tdId); td.innerHTML=html; } });}function saveCountryNotes(ccode){ var editBox=dwr.util.byId(ccode+'NotesEditBox'); var newNotes=editBox.value; CountryDB.saveCountryNotes(ccode,newNotes, { callback:function(newNotes) { var ccode=newNotes[0]; var notes=newNotes[1]; var notesHtml=getNotesHtml(ccode,notes); var td=dwr.util.byId(ccode+"_NotesCell"); td.innerHTML=notesHtml; } });} There are lots of functions for table samples, and we go through each one of them. The first is the selectLetter() function. This function gets the selected letter from the select element and calls the CountryDB.getCountries() remoted Java method. The callback function is setCountryRows. This function receives the return value from the Java getCountries() method, that is List<List<String>>, a List of Lists of Strings. The second function is addLetters(letters), and it is a callback function for theAppContent.getLetters() method, which simply returns letters from A to Z. The addLetters() function uses the DWR utility functions to populate the letter list. Then there is a callback function for the CountryDB.getCountries() method. The parameter for the function is an array of countries that begin with a specified letter. Each array element has a format: Name, Long name, (country code) Code, Capital, Notes. The purpose of this function is to populate the table with country data; and let's see how it is done. The variable, cellFuncs, holds functions for retrieving data for each cell in a column. The parameter named data is an array of country data that was returned from the Java class. The table is populated using the DWR utility function, addRows(). The cellFuncs variable is used to get the correct data for the table cell. The cellCreator function is used to create custom HTML for the table cell. Default implementation generates just a td element, but our custom implementation generates the td-element with the div placeholder for user notes. The getNotesHtml() function is used to generate the div element with the event listener for double-click. The editCountryNotes() function is called when the table cell is double-clicked. The function creates input fields for editing notes with the Save and Cancel buttons. The cancelEditNotes() and saveCountryNotes() functions cancel the editing of new notes, or saves them by calling the CountryDB.saveCountryNotes() Java method. The following screenshot shows what the sample looks like with the populated table: Now that we have added necessary functions to the web page we can test the application. Testing Tables and Lists The application should be ready for testing if we have had the test environment running during development. Eclipse automatically deploys our new code to the server whenever something changes. So we can go right away to the test page http://127.0.0.1:8080/DWREasyAjax. On clicking Tables and lists we can see the page we have developed. By selecting some letter, for example "I" we get a list of all the countries that start with letter "I" (as shown in the previous screenshot). Now we can add notes to countries. We can double-click any table cell under Notes. For example, if we want to enter notes to Iceland, we double-click the Notes cell in Iceland's table row, and we get the edit box for the notes as shown in the following screenshot: The edit box is a simple text input field. We didn't use any forms. Saving and canceling editing is done using JavaScript and DWR. If we press Cancel, we get the original notes from the CountryDB Java class using DWR and saving also uses DWR to save data. CountryDB.saveCountryNotes() takes the country code and the notes that the user entered in the edit box and saves them to the CSV file. When notes are available, the application will show them in the country table together with other country information as shown in the following screenshot: Afterword The sample in this section uses DWR features to get data for the table and list from the server. We developed the application so that most of the application logic is written in JavaScript and Java beans that are remoted. In principle, the application logic can be thought of as being fully browser based, with some extensions in the server. Implementing Field Completion Nowadays, field completion is typical of many web pages. A typical use case is getting a stock quote, and field completion shows matching symbols as users type letters. Many Internet sites use this feature. Our sample here is a simple license text finder. We enter the license name in the input text field, and we use DWR to show the license names that start with the typed text. A list of possible completions is shown below the input field. The following is a screenshot of the field completion in action: Selected license content is shown in an iframe element from http://www.opensource.org. Server Code for Field Completion We will re-use some of the classes we developed in the last section. AppContent is used to load the sample page, and the DBUtils class is used in the LicenseDB class. The LicenseDB class is shown here: package samples;import java.util.List;import java.util.Vector;public class LicenseDB{ private DBUtils dbUtils=new DBUtils(); public LicenseDB() { dbUtils.initFileDB("licenses.csv"); } public List<String> getLicensesStartingWith(String startLetters) { List<String> list=new Vector<String>(); List<String> licenses=dbUtils.getCSVStrings(startLetters); for(String license : licenses) { list.add(license.split(",")[0]); } return list; } public String getLicenseContentUrl(String licenseName) { List<String> licenses=dbUtils.getCSVStrings(licenseName); if(licenses.size()>0) { return licenses.get(0).split(",")[1]; } return ""; }} The getLicenseStartingWith() method goes through the license names and returns valid license names and their URLs. Similar to the data in the previous section, license data is in a CSV file named licenses.csv in the package directory. The following is an excerpt of the file content: Academic Free License, http://opensource.org/licenses/afl-3.0.phpAdaptive Public License, http://opensource.org/licenses/apl1.0.phpApache Software License, http://opensource.org/licenses/apachepl-1.1.phpApache License, http://opensource.org/licenses/apache2.0.phpApple Public Source License, http://opensource.org/licenses/apsl-2.0.phpArtistic license, http://opensource.org/licenses/artistic-license-1.0.php... There are quite a few open-source licenses. Some are more popular than others (like the Apache Software License) and some cannot be re-used (like the IBM Public License). We want to remote the LicenseDB class, so we add the following to the dwr.xml file. <create creator="new" javascript="LicenseDB"> <param name="class" value="samples.LicenseDB"/> <include method="getLicensesStartingWith"/> <include method="getLicenseContentUrl"/></create> Client Code for Field Completion The following script element will go in the index.jsp page. <script type='text/javascript' src='/DWREasyAjax/dwr/interface/LicenseDB.js'></script> The HTML for the field completion is as follows: <h3>Field completion</h3><p>Enter Open Source license name to see it's contents.</p><input type="text" id="licenseNameEditBox" value="" onkeyup="showPopupMenu()" size="40"/><input type="button" id="showLicenseTextButton" value="Show license text" onclick="showLicenseText()"/><div id="completionMenuPopup"></div><div id="licenseContent"></div> The input element, where we enter the license name, listens to the onkeyup event which calls the showPopupMenu() JavaScript function. Clicking the Input button calls the showLicenseText() function (the JavaScript functions are explained shortly). Finally, the two div elements are place holders for the pop-up menu and the iframe element that shows license content. For the pop-up box functionality, we use existing code and modify it for our purpose (many thanks to http://www.jtricks.com). The following is the popup.js file, which is located under the WebContent | js directory. //<script type="text/javascript"><!--/* Original script by: www.jtricks.com * Version: 20070301 * Latest version: * www.jtricks.com/javascript/window/box.html * * Modified by Sami Salkosuo. */// Moves the box object to be directly beneath an object.function move_box(an, box){ var cleft = 0; var ctop = 0; var obj = an; while (obj.offsetParent) { cleft += obj.offsetLeft; ctop += obj.offsetTop; obj = obj.offsetParent; } box.style.left = cleft + 'px'; ctop += an.offsetHeight + 8; // Handle Internet Explorer body margins, // which affect normal document, but not // absolute-positioned stuff. if (document.body.currentStyle && document.body.currentStyle['marginTop']) { ctop += parseInt( document.body.currentStyle['marginTop']); } box.style.top = ctop + 'px';}var popupMenuInitialised=false;// Shows a box if it wasn't shown yet or is hidden// or hides it if it is currently shownfunction show_box(html, width, height, borderStyle,id){ // Create box object through DOM var boxdiv = document.getElementById(id); boxdiv.style.display='block'; if(popupMenuInitialised==false) { //boxdiv = document.createElement('div'); boxdiv.setAttribute('id', id); boxdiv.style.display = 'block'; boxdiv.style.position = 'absolute'; boxdiv.style.width = width + 'px'; boxdiv.style.height = height + 'px'; boxdiv.style.border = borderStyle; boxdiv.style.textAlign = 'right'; boxdiv.style.padding = '4px'; boxdiv.style.background = '#FFFFFF'; boxdiv.style.zIndex='99'; popupMenuInitialised=true; //document.body.appendChild(boxdiv); } var contentId=id+'Content'; var contents = document.getElementById(contentId); if(contents==null) { contents = document.createElement('div'); contents.setAttribute('id', id+'Content'); contents.style.textAlign= 'left'; boxdiv.contents = contents; boxdiv.appendChild(contents); } move_box(html, boxdiv); contents.innerHTML= html; return false;}function hide_box(id){ document.getElementById(id).style.display='none'; var boxdiv = document.getElementById(id+'Content'); if(boxdiv!=null) { boxdiv.parentNode.removeChild(boxdiv); } return false;}//--></script> Functions in the popup.js file are used as menu options directly below the edit box. The show_box() function takes the following arguments: HTML code for the pop-up, position of the pop-up window, and the "parent" element (to which the pop-up box is related). The function then creates a pop-up window using DOM. The move_box() function is used to move the pop-up window to its correct place under the edit box and the hide_box() function hides the pop-up window by removing the pop-up window from the DOM tree. In order to use functions in popup.js, we need to add the following script-element to the index.jsp file: <script type='text/javascript' src='js/popup.js'></script> Our own JavaScript code for the field completion is in the index.jsp file. The following are the JavaScript functions, and an explanation follows the code: function showPopupMenu(){ var licenseNameEditBox=dwr.util.byId('licenseNameEditBox'); var startLetters=licenseNameEditBox.value; LicenseDB.getLicensesStartingWith(startLetters, { callback:function(licenses) { var html=""; if(licenses.length==0) { return; } if(licenses.length==1) { hidePopupMenu(); licenseNameEditBox.value=licenses[0]; } else { for (index in licenses) { var licenseName=licenses[index];//.split(",")[0]; licenseName=licenseName.replace(/"/g,"&quot;"); html+="<div style="border:1px solid #777777;margin-bottom:5;" onclick="completeEditBox('"+licenseName+"');">"+licenseName+"</div>"; } show_box(html, 200, 270, '1px solid','completionMenuPopup'); } } });}function hidePopupMenu(){ hide_box('completionMenuPopup');}function completeEditBox(licenseName){ var licenseNameEditBox=dwr.util.byId('licenseNameEditBox'); licenseNameEditBox.value=licenseName; hidePopupMenu(); dwr.util.byId('showLicenseTextButton').focus();}function showLicenseText(){ var licenseNameEditBox=dwr.util.byId('licenseNameEditBox'); licenseName=licenseNameEditBox.value; LicenseDB.getLicenseContentUrl(licenseName,{ callback:function(licenseUrl) { var html='<iframe src="'+licenseUrl+'" width="100%" height="600"></iframe>'; var content=dwr.util.byId('licenseContent'); content.style.zIndex="1"; content.innerHTML=html; } });} The showPopupMenu() function is called each time a user enters a letter in the input box. The function gets the value of the input field and calls the LicenseDB. getLicensesStartingWith() method. The callback function is specified in the function parameters. The callback function gets all the licenses that match the parameter, and based on the length of the parameter (which is an array), it either shows a pop-up box with all the matching license names, or, if the array length is one, hides the pop-up box and inserts the full license name in the text field. In the pop up box, the license names are wrapped within the div element that has an onclick event listener that calls the completeEditBox() function. The hidePopupMenu() function just closes the pop-up menu and the competeEditBox() function inserts the clicked license text in the input box and moves the focus to the button. The showLicenseText() function is called when we click the Show license text button. The function calls the LicenseDB. getLicenseContentUrl() method and the callback function creates an iframe element to show the license content directly from http://www.opensource.org, as shown in the following screenshot: Afterword Field completion improves user experience in web pages and the sample code in this section showed one way of doing it using DWR. It should be noted that the sample for field completion presented here is only for demonstration purposes.

The unsung heroes of every application are the simple things like buttons, menus, and toolbars. In this article by Shea Frederick, Steve 'Cutter' Blades, and Colin Ramsay, we will cover how to add these items to our applications. Our example will contain a few different types of buttons, both with and without menus. A button can simply be an icon, or text, or both. Toolbars also have some mechanical elements such as spacers and dividers that can help to organize the buttons on your toolbars items. We will also cover how to make these elements react to user interaction. A toolbar for every occasion Just about every Ext component—panels, windows, grids can accept a toolbar on either the top or the bottom. The option is also available to render the toolbar standalone into any DOM element in our document. The toolbar is an extremely flexible and useful component that will no doubt be used in every application. Ext.Toolbar: The main container for the buttons Ext.Button: The primary handler for button creation and interaction Ext.menu: A menu Toolbars Our first toolbar is going to be rendered standalone in the body of our document. We will add one of each of the main button types, so we can experiment with each: Button—tbbutton: This is the standard button that we are all familiar with. Split Button—tbsplit: A split button is where you have a default button action and an optional menu. These are used in cases where you need to have many options in the same category as your button, of which there is a most commonly used default option. Menu—tbbutton+menu: A menu is just a button with the menu config filled in with options. Ext.onReady(function(){ new Ext.Toolbar({ renderTo: document.body, items: [{ xtype: 'tbbutton', text: 'Button' },{ xtype: 'tbbutton', text: 'Menu Button', menu: [{ text: 'Better' },{ text: 'Good' },{ text: 'Best' }] },{ xtype: 'tbsplit', text: 'Split Button', menu: [{ text: 'Item One' },{ text: 'Item Two' },{ text: 'Item Three' }] }] });}); As usual, everything is inside our onReady event handler. The items config holds all of our toolbars elements—I say elements and not buttons because the toolbar can accept many different types of Ext components including form fields—which we will be implementing later on in this article. The default xtype for each element in the items config is tbbutton. We can leave out the xtype config element if tbbutton is the type we want, but I like to include it just to help me keep track. The button Creating a button is fairly straightforward; the main config option is the text that is displayed on the button. We can also add an icon to be used alongside the text if we want to. Here is a stripped-down button: { xtype: 'tbbutton', text: 'Button'} Menu A menu is just a button with the menu config populated—it's that simple. The menu items work along the same principles as the buttons. They can have icons, classes, and handlers assigned to them. The menu items could also be grouped together to form a set of option buttons, but first let's create a standard menu. This is the config for a typical menu config: { xtype: 'tbbutton', text: 'Button', menu: [{ text: 'Better' },{ text: 'Good' },{ text: 'Best' }]} As we can see, once the menu array config is populated, the menu comes to life. To group these menu items together, we would need to set the group config and the boolean checked value for each item: menu: [{ text: 'Better', checked: true, group: 'quality'}, { text: 'Good', checked: false, group: 'quality'}, { text: 'Best', checked: false, group: 'quality'}] Split button The split button sounds like a complex component, but it's just like a button and a menu combined, with a slight twist. By using this type of button, you get to use the functionality of a button while adding the option to select an item from the attached menu. Clicking the left portion of the button that contains the text triggers the button action. However, clicking the right side of the button, which contains a small down arrow, triggers the menu. { xtype: 'tbsplit', text: 'Split Button', menu: [{ text: 'Item One' },{ text: 'Item Two' },{ text: 'Item Three' }]} Toolbar item alignment, dividers, and spacers By default, every toolbar aligns elements to the leftmost side. There is no alignment config for a toolbar, so if we want to align all of the toolbar buttons to the rightmost side, we need to add a fill as the first item in the toolbar. If we want to have items split up between both the left and right sides, we can also use a fill: { xtype: 'tbfill'} Pop this little guy in a tool-bar wherever you want to add space and he will push items on either side of the fill to the ends of the tool bar, as shown below: We also have elements that can add space or vertical dividers, like the one used between the Menu Button and the Split Button. The spacer adds a few pixels of empty space that can be used to space out buttons, or move elements away from the edge of the toolbar: { xtype: 'tbspacer'} A divider can be added in the same way: { xtype: 'tbseparator'} Shortcuts Ext has many shortcuts that can be used to make coding faster. Shortcuts are a character or two that can be used in place of a configuration object. For example, consider the standard toolbar filler configuration: { xtype: 'tbfill'} The shortcut for a toolbar filler is a hyphen and a greater than symbol: '->' Not all of these shortcuts are documented. So be adventurous, poke around the source code, and see what you can find. Here is a list of the commonly-used shortcuts:

Displaying author picture on posts Did you like the previous recipe in the first part? I hope you did! But personally, I must admit that even though displaying author information looks very cool, something is missing from the previous recipe. Can you guess what is it? It is a picture of the author, of course. Even if your author-related information is precise and complete, a picture is still essential. This is because it is the easiest, and quickest, way for a reader to recognize an author. But sadly, WordPress can't handle author pictures by default. Let's learn how to create a hack that will allow us to display the author's picture in the way that we want to. Getting ready As we'll be using author pictures in this recipe, you should start by requesting a picture of all of your authors. Although it isn't necessary, it will be really better if all of the pictures have the same width and height. A square of 80 to 110 pixels is a good standard. Also, make sure that all of your pictures have the same format, such as .jpg, .png, or .gif. How to do it Now that you have collected pictures of all of your authors, we can start to hack WordPress and insert author pictures in the posts First, you have to rename your images with the author IDs. You can also use author's last name if you prefer, but in this example I am going to use their IDs. Once you have your renamed authors' pictures, upload them to the wp-content/themes/yourtheme/images directory. Open the file single.php and add the following code within the loop: <img src="<?php bloginfo('template_url); ?>/images/<?php the_author_ID(); ?>.jpg" alt="<?php the_author(); ?>" /> Save the single.php file and you're done. Each post now displays a picture of its author! How it works The working of this code is pretty simple. You simply concatenated the result of the the_author_ID() function with the theme URL to build an absolute URL to the image. As the images are named with the author ID (for example, 1.jpg, 4.jpg, 17.jpg, and so on), the the_author_ID() function gives us the name of the picture to be displayed. You just have to add the .jpg extension. There's more... Now that you've learnt how to display the picture of the current author, you should definitely use this recipe to enhance the previous recipe. The following code will retrieve the author information, and display the author picture as we have learnt earlier: <div id="author-info"><h2>About the author: <?php the_author();?></h2><img src="<?php bloginfo('template_url); ?>/images/<?php the_author_ID(); ?>.jpg" alt="<?php the_author(); ?>" /><?php the_author_description(); ?><?php the_author();?>'s website: <a href="<?php the_author_url(); ?>"><?php the_author_url(); ?></a><br />Other posts by <?php the_author_posts_link(); ?></div><!--/author-info--> The outcome of the preceding piece of code will look similar to the following screenshot: Displaying the author's gravatar picture on posts Gravatars (which stands for Globally recognized avatars) is a popular service, that allows you to associate an avatar image to your email address. On October 18, 2007, Automattic (The company behind WordPress) acquired Gravatar. Since WordPress 2.5 the popular blogging engine is fully gravatar-compatible, which results, in the ability to include gravatars in comments. In this recipe, I'll show you how to modify the previous code to use the author gravatar instead of a personal picture. Getting ready As we're going to use Gravatars, you (and each of your authors) first need a gravatar account. Carry out the following steps to create a gravatar account and associate an image to your email address. Go to the web site http://en.gravatar.com/site/signup, and enter your email address into the text field. Gravatar will send you a confirmation via email. Check your emails and open the one received from Gravatar. Click on the link to confirm your email address. Choose a username and a Password for your account. Once your username and Password has been created successfully, you'll see a text that reads Whoops, looks like you don't have any images yet! Add an image by clicking here. Click on the given link, and choose to upload a picture from your computer's hard drive, or the Internet. Once you are done choosing and cropping (if necessary) your picture, you have to rate it. Click on G unless—except, if your avatar is meant for mature audiences only. Done! You now have your own gravatar. How to do it Open the file single.php from the theme you're using and paste the following code: $md5 = md5(get_the_author_email());$default = urlencode( 'http://www.yoursite.com/wp-content/themes/yourtheme/images/default_avatar.gif' );echo "<img src='http://www.gravatar.com/avatar.php?gravatar_id=$md5&amp;size=60&amp;default=$default' alt='' />"; How it works The first thing to do is to get an md5 sum from the author's email address. To do so, I used the php md5() function along with the get_the_author_email() function. I didn't use the_author_email() because this function directly prints the result without allowing you to manipulate it with php I then encoded the URL of a default picture that is to be shown if the author hasn't signed up to Gravatar yet. Once done, the gravatar can be displayed. To do so, visit the web site: http://www.gravatar.com/avatar.php with the following parameters: gravatar_id: The gravatar id, which is an md5 sum of the user email size: The gravatar size in pixels default:The absolute URL to an image which will be used as a default image if the author hasn't signed up to gravatar yet Adding moderation buttons to the comments A common problem with comments is spam. Sure, you can moderate comments and use the Akismet plugin. However, sometimes someone leaves a normal comment, you approve it, and then the spammer—who knows that his comments aren't being accepted by the moderator—starts to spam your blog. Even though you can do nothing against this (except moderating all of the comments), a good idea is to either add spam and delete buttons to all of the comments. This way, if you see a comment saying spam while reading your blog, then you can edit it, delete it, or mark it as spam. I got this useful tip from Joost de Valk, who blogs at www.yoast.com Getting ready The following screenshot shows normal comments without the edit, delete and spam buttons: There's nothing complicated at all with this recipe. However, you must be sure to know which kind of blog the users are allowed to edit or delete your comments. For a list of actions and user roles, see the section named Controlling what users can do, which is later in this article. How to do it Open the file functions.php and paste the following piece of code: function delete_comment_link($id){if (current_user_can('edit_post')){echo '| <a href="'.admin_url("comment.php?action=cdc&c=$id").'">del</a> ';echo '| <a href="'.admin_url("comment.php?action=cdc&dt=spam&c=$id").'">spam</a>';}} Save the file functions.php and open the file comments.php. Find the comments loop and add the following lines: <?phpedit_comment_link();delete_comment_link(get_comment_ID());?> Save the file comments.php and visit your blog. You now have three links on each of the comments to edit, to delete (del), and to mark as spam as shown in the following screenshot: How it works In this recipe we started by creating a function. This function first verifies whether the current user has the right to edit posts. If yes, then the admin URLs to mark the comment as spam or delete it are created and displayed. In the file comments.php, we have used the edit_comment_link(), which is a built-in WordPress function. Some themes include this by default. We then used the comment ID as a parameter to the delete_comment_link() function that you had created earlier.

Customizing page management with more features The Ext Manage Pages portlet not only clones the out of the box Manage Pages portlet, but it also extends the model and service — supporting customized data, for example, Keywords. We can make these Keywords localized too.   Adding localized feature Liferay portal is designed to handle as many languages as you want to support. By default, it supports up to 22 languages. When a page is loading, the portal will detect the language, pull up the corresponding language file, and display the text in the correct language. We want the Keywords to be localized too. For example, the default language is English (United States) and the localized language is Deutsch (Deutschland). Thus, you have the ability to enter not only the Name and HTML Title in German, but also the Keywords in German. As shown in the following screenshot, when you change the language of the page in German using the language portlet, you will see the entire web site changed to German, including the portlet title and input fields. For example, the title of the portlet now has the Ext Seiteneinstellungen value and the Keywords now become Schlüsselwörter. How do we implement this feature? In other words, how do we customize the language display in the page management? Let's add the localized feature for the Ext Manage Pages portlet. Extending model for locale First of all, we need to extend the model and to implement that model in order to support the localized feature. For the ExtLayout model, let's add the locale method first. Locate the ExtLayout.java file from the com.ext.portlet.layout.model package in the /ext/ext-service/src folder, and open it. Add the following lines before the line } in ExtLayout.java and save it: public String getKeywords(Locale locale);public String getKeywords(String localeLanguageId);public String getKeywords(Locale locale, boolean useDefault);public String getKeywords(String localeLanguageId, boolean useDefault);public void setKeywords(String keywords, Locale locale); As shown in the code above, it adds getting and setting methods for the Keywords field with locale features. Now let's add the implementation for the ExtLayout model: Locate the ExtLayoutImpl.java file from the com.ext.portlet.layout.model.impl package in the /ext/ext-impl/src folder and open it. Add the following lines before the last } in ExtLayoutImpl.java file and save it: public String getKeywords(Locale locale) { String localeLanguageId = LocaleUtil.toLanguageId(locale); return getKeywords(localeLanguageId);}public String getKeywords(String localeLanguageId) { return LocalizationUtil.getLocalization(getKeywords(), localeLanguageId);}public String getKeywords(Locale locale, boolean useDefault) { String localeLanguageId = LocaleUtil.toLanguageId(locale); return getKeywords(localeLanguageId, useDefault);}public String getKeywords(String localeLanguageId, boolean useDefault) { return LocalizationUtil.getLocalization( getKeywords(), localeLanguageId, useDefault);}public void setKeywords(String keywords, Locale locale) { String localeLanguageId = LocaleUtil.toLanguageId(locale); if (Validator.isNotNull(keywords)) { setKeywords(LocalizationUtil.updateLocalization( getKeywords(), "keywords", keywords, localeLanguageId)); } else { setKeywords(LocalizationUtil.removeLocalization( getKeywords(), "keywords", localeLanguageId)); }} As shown in the code above, it adds implementation for get and set methods of the ExtLayout model. Customizing language properties Language files have locale-specific definitions. By default, Language.properties (at /portal/portal-impl/src/content) contains English phrase variations further defined for United States, while Language_de.properties (at /portal/portal-impl/src/content) contains German phrase variations further defined for Germany. In Ext, Language-ext.properties (available at /ext/ext-impl/src/content) contains English phrase variations further defined for United States, while Language-ext_de.properties (should be available at /ext/ext-impl/src/content) contains German phrase variations further defined for Germany. First, let's add a message in Language-ext.properties, by using the following steps: Locate the Language-ext.properties file in the /ext/ext-impl/src/content folder and open it. Add the following line after the line view-reports=View Reports for Books and save it. keywords=Keywords This code specifies the keywords message key with a Keywords value in English: Then we need to add German language feature in Language-ext_de.properties as follows: Create a language file Language-ext_de.properties in the /ext/ext-impl/src/content folder and open it. Add the following lines at the beginning and save it: ## Portlet namesjavax.portlet.title.EXT_1=Berichtejavax.portlet.title.jsp_portlet=JSP Portletjavax.portlet.title.book_reports=Berichte für das Buchjavax.portlet.title.extLayoutManagement=Ext Seiteneinstellungenjavax.portlet.title.extCommunities=Ext Communities## Messagesview-reports=Ansicht-Berichte für Bücherkeywords=Schlüsselwörter## Category titlescategory.book=Buch## Model resourcesmodel.resource.com.ext.portlet.reports.model.ReportsEntry= Buch ## Action namesaction.ADD_BOOK=Fügen Sie Buch hinzu As shown in the code above, it specifies the same keys as that of Language-ext.properties. But all the keys' values were specified in German instead of English. For example, the message keywords has a Schlüsselwörter value in German. In addition, you can set German as the default language and Germany as the default country if it is required. Here are the simple steps to do so: Locate the system-ext.properties file in the /ext/ext-impl/src folder and open it. Add the following lines at the end of system-ext.properties and save it: user.country=DEuser.language=de The code above sets the default locale — the language German (Deutsch) and the country Germany (Deutschland). In general, there are many language files, for example Language-ext.properties and Language-ext_de.properties, and some language files would overwrite others in runtime loading. For example, Languageext_de.properties will overwrite Language-ext.properties when the language is set as German. These are the three simple rules which indicate the priorities of these language files: The ext versions take precedence over the non-ext versions. The language-specific versions, for example _de, take precedence over the non language-specific versions. The location-specific versions, such as -ext_de, take precedence over the non location-specific versions. For instance, the following is a ranking from bottom to top for the German language: Language-ext_de.properties Language_de.properties Language-ext.properties Language.properties

The Rotating Post Titles with Post Preview gadget lists all your blog posts classified according to labels or categories. Blogger uses Labels to classify posts while Wordpress uses Categories for the same. Clicking on a Label or a category in the sidebar of a blog brings up all posts associated with that particular label or category. However, you will see only posts associated with that one label. In this gadget post titles are grouped under their respective labels. In this gadget in one look you can see all the post titles in that blog and all the labels in it. Thus you get a full summary of the blog. Hovering on a post title shows the Post Preview in the top pane. You can then click on it to go to that post to read it in full detail. What is Google AJAX feed API? AJAX (shorthand for asynchronous JavaScript and XML) is a web development technique which retrieves data from the server asynchronously in the background without interfering with the display, and behaviour of the existing page. The whole page is not refreshed when data is retrieved. Only that section of the page which is a part of the gadget shows the data brought. With the Google AJAX Feed API, you can retrieve feeds and mash them up using Javascript. In this gadget, we will retrieve the post titles from the label feeds and display them using Javascript code. See picture below: This gadget shows list of posts grouped by label from my blog http://www.blogdoctor.me. Four post titles from three labels are shown but the code can be modified to show all posts from all labels (categories). This label is also shown as Gadget No 4 in My Gadget Showcase blog. The cursor autoscrolls down the post titles, and each post preview is shown at the top as an excerpt for five seconds before moving on to the next post. Obtaining the Google AJAX API Key The first step in installing the above gadget is to get the Google AJAX API Key. It is free and you can easily obtain it for any site blog or page by signing up for the key at the API key signup page. Type in your blog address in the My web site URL text box and click the "Generate API Key" button. On the resulting page copy the key and paste it in code below as shown. Customizing the code In the code below replace PASTE AJAX API KEY HERE with your actual key obtained above. <!-- ++Begin Dynamic Feed Wizard Generated Code++ --><!-- // Created with a Google AJAX Search and Feed Wizard // http://code.google.com/apis/ajaxsearch/wizards.html --> <!-- // The Following div element will end up holding the actual feed control. // You can place this anywhere on your page. --><div id="content"> <span style="color:#676767;font-size:11px;margin:10px;padding:4px;">Loading...</span> </div><!-- Google Ajax Api --> <script src="http://www.google.com/jsapi?key=PASTE AJAX API KEY HERE" type="text/javascript"></script> <!-- Dynamic Feed Control and Stylesheet --> <script src="http://www.google.com/uds/solutions/dynamicfeed/gfdynamicfeedcontrol.js" type="text/javascript"></script> <style type="text/css"> @import url("http://www.google.com/uds/solutions/dynamicfeed/gfdynamicfeedcontrol.css"); </style><script type="text/javascript"> google.load('feeds', '1'); function OnLoad() { var feeds = [ { title: 'LABEL_1', url: 'http://MYBLOG.blogspot.com/feeds/posts/default/-/LABEL1?max-results=100' }, { title: 'LABEL_2', url: 'http://MYBLOG.blogspot.com/feeds/posts/default/-/LABEL2?max-results=100' }, { title: 'LABEL_3', url: 'http://MYBLOG.blogspot.com/feeds/posts/default/-/LABEL3?max-results=100' } ]; var options = { stacked : true, horizontal : false, title : "Posts from BLOG_TITLE" }; new GFdynamicFeedControl(feeds, 'content', options); document.getElementById('content').style.width = "200px"; } google.setOnLoadCallback(OnLoad); </script> In the above code replace LABEL_1, LABEL_2 and LABEL_3 and LABEL1, LABEL2 and LABEL3 by respective Label Names and BLOG_TITLE by the actual title of your blog. Also replace MYBLOG by actual blog subdomain. This is for blogspot blogs only. For Wordpress blog you will have to replace the label feeds:: http://MYBLOG.blogspot.com/feeds/posts/default/-/LABEL1?max-results=100 http://MYBLOG.blogspot.com/feeds/posts/default/-/LABEL2?max-results=100 http://MYBLOG.blogspot.com/feeds/posts/default/-/LABEL3?max-results=100 by the Category feed URLs from Wordpress blog. After customizing the above code in Blogger paste it in a HTML gadget while in Wordpress paste it in a Text widget. Further Customization To show more than four posts per label or category, you will have to modify the following Javascript code file: http://www.google.com/uds/solutions/dynamicfeed/gfdynamicfeedcontrol.js In the above mentioned Javascript code file, alter the following code line in it : GFdynamicFeedControl.DEFAULT_NUM_RESULTS = 4; Change '4' to '1000' and save the file as a MODgfdynamicfeedcontrol.js file in a text editor like Notepad. Upload the file to a free host and replace the link of the file in the above code. To change the styling of the gadget, you will have to modify the following file: http://www.google.com/uds/solutions/dynamicfeed/gfdynamicfeedcontrol.css Then save the modified file and upload it to a free host and replace its link in the above code. Working Example Posts from The Blog Doctor Change Post Formatting According to Author. by Vin - 30 Apr 2008 If you have a Team Blog made up of two authors you can change the formatting of the posts written by one author to ... Template Calling all Newbie Bloggers! Upgrade Classic Template without the "UPGRADE YOUR TEMPLATE" button. The Minimalist Minima Photoblog Template. Making the COMMENTS Link more User Friendly. CSS Change Post Formatting According to Author. Free CSS Navigation Menus in Blogger. Fix the Page Elements Layout Editor No Scrollbar Problem. Frame the Blog Header Image. Blogger Hacks Rounded Corner Headers for Blogger. Timestamp under the Date and Other Hacks. Add Icon to Post Titles. Many Headers In One Blog.   Summary The Rotating Post Titles with Post Preview gadget provides an at-a glance summary of your blog. All the posts are grouped by label or category and are linked to their post pages. The constantly rotating post excerpts at the top draws the attention of the reader and gets him/her more involved and eager to explore your blog. This increases the traffic and decreases the bounce rate of visitors from your blog.nara