How-To Tutorials

Background Information The User Management Module is created for a website called 'TaleWiki'. TaleWiki is a website about user submitted tales and stories, which can be added, modified, deleted, and published by the user, depending on the Role or Privileges the user has. Taking into consideration this small piece of information, we will design and create tables that will become the back-end for the User Management functionality. Designing the Tables To Design and to create tables, we need to understand the entities and their relationship, the schema corresponding to the entities, and then the table creation queries. If we go step-by-step, we can say that following are the steps in designing the tables for the User Management module: Designing the E-R model Deriving the Schema from the E-R model Creating the Tables from the Schema So, let us follow the steps. Designing the E-R Model To design the E-R model, let us first look at what we have understood about the data required by the functionalities, which we just discussed. It tells us that 'only the Users with a particular Role can access TaleWiki'. Now we can consider this as our 'problem statement' for our E-R model design. If you observe closely, the statement is vague. It doesn't tell about the particular Roles. However, for the E-R design, this will suffice as it clearly mentions the two main entities, if we use the E-R terminology. They are: User Role Let us look at the User entity. Now this entity represents a real-world user. It is not difficult to describe its attributes. Keeping a real-world user in mind and the functionalities discussed for managing a user, we can say that the User entity should have the following attributes: Id: It will identify the different users, and it will be unique. User name: The name which will be displayed with the submitted story. Password: The pass key with which the user will be authenticated. First name: The first name of the user. Last name: The last name of the user. The combination of the first and last name will be the real name of the user. Age: The age of the user. This will help in deciding whether or not the user is of required age which is 15. E-mail id: The email id of the user in which he/she would like to get emails from the administrator regarding the submissions. Country: To keep track of the 'geographic distribution' of users. Role: To know what privileges are granted for the user. The Role is required because the problem statement mentions "User with a particular Role". The entity diagram will be as follows: Next, let us look at the Role entity. Role, as already discussed, will represent the privileges a user can have. And as these privileges are static, the Role entity won't need to have the attribute to store the privileges. The important point about the static privileges that you have to keep in mind is that they will have to be programmatically checked against a user. In other words, the privileges are not present in the database and there can only be a small number of Roles with predefined privileges. Keeping this in mind, we can say that the Role entity will have the following attributes: Id: The unique identification number for the Role. Name: The name with which the id will be known and that will be displayed along with the user name. The entity diagram for Role entity will be as follows: We have completed two out of three steps in designing the E-R model. Next, we have to define how the User entity is related with the Role entity. From the problem statement we can say that a user will definitely have a Role. And the functionality for assigning the Role tells us that a user can have only one Role. So if we combine these two, we can say that 'A user will have only one Role but different users can have the same Role'. In simple terms, a Role—let us say normal user—can be applied to different users such as John, or Jane. However, the users John or Jane cannot be both normal user as well as administrator. In technical terms, we can say that a Role has a one-to-many relationship with the User entity and a User has a many-to-one relationship with a Role. Diagrammatically, it will be as follows: One piece of the puzzle is still left. If you remember there is one more entity called Story. We had found that each story had a submitter. The submitter is a user. So that means there is a relationship between the User and the Story entity. Now, a user, let us say, John or Jane, can submit many stories. However, the same story cannot be submitted by more than one user. On the basis of this we can say that a User has a many-to-one relationship with a Story and a Story has a many-to-one relationship with a User. According to the E-R diagram it will be as follows: The final E-R design including all the entities and the attributes will be as follows: That completes our E-R design step. Next, we will derive the schema from theE-R model. Deriving the Schema We have all we need to derive the schema for our purpose. While deriving a schema from an E-R model, it is always a good choice to start with the entities at the 'one' end of a 'one-to-many' relationship. In our case, it is the Role entity. As we did in the previous chapter, let us start by providing the details for each attribute of the Role entity. The following is the schema for the Role entity: Attribute Data type of the attribute Length of the acceptable value Id Integer 10 Name Varchar 25 >Next, let us look at the schema of the User entity. As it is at the 'many' end of the 'one-to-many' relationship, the Role attribute will be replaced by the Id of Role. The schema will be as follows: Attribute Data type of the attribute Length of the acceptable value Id Integer 10 User name Varchar 50 First name Varchar 50 Last name Varchar 50 Password Varchar 15 Age Integer 3 e-mail id Varchar 25 Country Varchar 20 Id of the Role Integer 10 Now, let us visit the Story entity. The attributes of the entity were: Id: This is the Primary key attribute as it can uniquely identify a story. Heading: The title of the story. Body text: The body of the story. Date of Submission: The day the user submitted the story. Source: The source from where the story was found. If it is written by the user himself/herself, the source will be the user's id. Genre: The category of the story. User: The user who submitted the story. Name of the attribute Data type of the attribute Length of the acceptable value Id Integer 10 Title Varchar 100 Body Text Varchar 1000 Date of Submission Date   Source Varchar 50 Status Varchar 15 Id of Genre Integer 10 Id of the User Integer 10 The schema has been derived and now we can move to the last part of the database design—creation of the tables. Creating the Tables Looking at the schema  required for tables in Ruby on Rails, here is the table creation statement for the Role schema: CREATE TABLE `roles` (`id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY ,`name` VARCHAR( 25 ) NOT NULL ,`description` VARCHAR( 100 ) NOT NULL) ENGINE = innodb; Next comes the table creation statement for the User schema. Note that here also we are following the one-to-many path, that is, the table at the 'one' end is created first. Whenever there is a one-to-many relationship between entities, you will have to create the table for the entity at the 'one' end. Otherwise you will not be able to create a foreign key reference in the table for the entity at the 'many' end, and if you try to create one, you will get an error (obviously). So here is the create table statement for the User schema: CREATE TABLE `users` (`id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY ,`user_name` VARCHAR( 50 ) NOT NULL ,`password` VARCHAR( 15 ) NOT NULL ,`first_name` VARCHAR( 50 ) NOT NULL ,`last_name` VARCHAR( 50 ) NOT NULL ,`age` INT( 3 ) NOT NULL ,`email` VARCHAR( 25 ) NOT NULL ,`country` VARCHAR( 20 ) NOT NULL ,`role_id` INT NOT NULL,CONSTRAINT `fk_users_roles` FOREIGN KEY (`role_id`) REFERENCES `role`( `id`) ON DELETE CASCADE) ENGINE = innodb; Next, let us create the table for Story, we will call it the 'tales' table, we will also add a foreign key reference to the users table in it. Here is the query for creating the table CREATE TABLE `tales` (`id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,`title` VARCHAR( 100 ) NOT NULL,`body_text` TEXT NOT NULL,`submission_date` DATE NOT NULL,`source` VARCHAR( 50 ) NOT NULL,`status` VARCHAR( 15 ) NOT NULL,`genre_id` INT NOT NULL,`user_id` INT NOT NULL,CONSTRAINT `fk_tales_genres` FOREIGN KEY (`genre_id`) REFERENCES genres( `id`)) ENGINE = innodb; Next, we will make a reference to the users table after executing the above query, with the following query: ALTER TABLE `tales` ADD FOREIGN KEY ( `user_id` ) REFERENCES `users` (`id`) ON DELETE CASCADE ; That completes our task of creating the required tables and making necessary changes to the tales table. The effect of this change will be visible to you when we implement session management in the next chapter. And incidentally, it completes the 'designing the tables' section. Let us move onto the development of the user management functionality. Summary In this article, we learned how to design and create tables for a User Management Module in Ruby on Rails. We looked at designing the E-R model, deriving the schema from the E-R model and creating the tables from the schema.

What is Minilang? The syntax of Minilang is simply well formed XML. Developers write XML that obeys a defined schema, this XML is then parsed by the framework and commands are executed accordingly. It is similar in concept to the Gang of Four Interpreter Pattern. We can therefore consider Minilang's XML elements to be "commands". Minilang is usually written in a simple method's XML file, which is specified at the top of the document like this: xsi:noNamespaceSchemaLocation="http://ofbiz.apache.org/dtds/ simple-methods.xsd"> Although Minilang's primary use is to code services and events, concepts from Minilang are also used to prepare data for screen widgets. Much of the simplicity of Minilang arises from the fact that variables are magically there for us to use. They do not have to be explicitly obtained, they are placed in the environment and we can take them as we wish. Should we wish to create a Map, we just use it, the framework will take care of its creation. For example: <set field="tempMap.fieldOne" from-field="parameters.fieldOne"/> will set the value of the fieldOne parameter to tempMap. If tempMap has already been used and is available, this will be added. If not, the Map will be created and the value added to the key fieldOne. Tools to Code XML Minilang is coded in XML and before it can be successfully parsed by the framework's XML parser, this XML must be well formed. Trying to code Minilang in a plain text editor like Notepad is not a wise move. Precious time can be wasted trying to discover a simple mistake such as a missing closing tag or a misspelled element. For this reason, before attempting to code Minilang services, make sure that you have installed some kind of XML editor and preferably one with an auto-complete feature. The latest versions of Eclipse come packaged with one and XML files are automatically associated to use this editor. Alternatively there are many editors available to download of varying functionality and price. For example XML Buddy (http://www.xmlbuddy.com), oXygen XML Editor (http://www.oxygenxml.com), or the heavyweight Altova XMLSpy (http://www.altova.com) Defining a Simple Service Minilang services are referred to as "simple" services. They are defined and invoked in the same way as a Java service. They can be invoked by the control servlet from the controller.xml file or from code in the same way as a Java service. In the following example we will write a simple service that removes Planet Reviews from the database by deleting the records. First open the file ${component:learning}widgetLearningForms.xml and find the PlanetReviews Form Widget. This widget displays a list of all reviews that are in the database. Inside this Form Widget, immediately under the update field element add: <field name="delete"><hyperlink target="RemovePlanetReview?reviewId=${reviewId}" description="Delete"/></field> Our list will now also include another column showing us a hyperlink we can click, although clicking it now will cause an error. We have not added the request-map to handle this request in the controller.xml. It will be added a little later. Defining the Simple Service In the file ${component:learning}servicedefservices.xml add a new service definition: <service name="learningRemovePlanetReview" engine="simple" location="org/ofbiz/learning/learning/LearningServices.xml" invoke="removePlanetReview"> <description>Service to remove a planet review</description> <attribute name="reviewId" type="String" mode="IN" optional="false"/> </service> Note that the engine type is simple. It is a common practice to group service definitions into their own XML file according to behavior. For instance, we may see that all services to do with Order Returns are in a file called services_returns.xml. So long as we add the <service-resource> element to the parent component's ofbiz-component.xml file and let the system know that this service definition file needs to be loaded, we can structure our service definitions sensibly and avoid huge definition files. It is not a common practice, however, to group service definitions by type. The type is abstracted from the rest of the system. When the service is invoked, the invoker doesn't care what type of service it is. It could be Java, it could be a simple service, it doesn't matter. All that matters is that the correct parameters are passed into the service and the correct parameters are passed out. For this reason, simple service definitions are found in the same XML files as Java service definitions. Writing the Simple Method Simple Method XML files belong in the component's script folder. In the root of ${component:learning} create the nested directory structure scriptorgofbizlearninglearning and in the final directory create a new file called LearningServices.xml. Before we add anything to this file we must make sure that the script directory is on the classpath. Open the file ${component:learning}ofbiz-component.xml and if it is not already there add <classpath type="dir" location="script"/> immediately underneath the other classpath elements. The location specified in the service definition can now be resolved. In our newly created file LearningServices.xml add the following code: <simple-methods xsi:noNamespaceSchemaLocation="http://www.ofbiz.org/dtds/ simple-methods.xsd"> <simple-method method-name="removePlantetReview" short-description="Delete a Planet Review"> <entity-one entity-name="PlanetReview" value-name="lookedUpValue"/> <remove-value value-name="lookedUpValue"/> </simple-method> </simple-methods> Finally all that is left is to add the request-map to the controller.xml: <request-map uri="RemovePlanetReview"> <security auth="true" https="true"/> <event type="service" invoke="learningRemovePlanetReview"/> <response name="success" type="view" value="ListPlanetReviews"/> <response name="error" type="view" value="ListPlanetReviews"/> </request-map> Since we have added a new service definition OFBiz must be restarted. A compilation is not needed. Restart and fire an http request ListPlanetReviews to webapp learning: Selecting Delete will delete this PlanetReview record from the database. Let's take a closer look at the line of code in the simple service that performs the lookup of the record that is to be deleted. <entity-one entity-name="PlanetReview" value-name="lookedUpValue"/> This command will perform a lookup on the PlanetReview entity. Since the command is <entity-one> the lookup criteria must be the primary key. This code is equivalent in Java to: GenericValue lookedUpValue = delegator.findByPrimaryKey ("PlanetReview", UtilMisc.toMap("reviewId", reviewId)); Already we can see that Minilang is less complicated. And this is before we take into account that the Java code above is greatly simplified, ignoring the fact that the delegator had to be taken from the DispatchContext, the reviewId had to be explicitly taken from the context Map and the method call had to be wrapped in a try/catch block. In Minilang, when there is a look up like this, the context is checked for a parameter with the same name as the primary key for this field, as specified in the entity definition for PlanetReview. If there is one, and we know there is since we have declared a compulsory parameter reviewId in the service definition, then the framework will automatically take it from the context. We do not need to do anything else. Simple Events We can call Minilang events, in the same way that we called Java events from the controller.xml. Just as Minilang services are referred to as simple services, the event handler for Minilang events is called "simple". Tell the control servlet how to handle simple events by adding a new <handler> element to the learning component's controller.xml file, immediately under the other <handler> elements: <handler name="simple" type="request" class="org.ofbiz.webapp.event.SimpleEventHandler"/> A common reason for calling simple events would be to perform the preparation and validation on a set of parameters that are passed in from an XHTML form. Don't forget that when an event is called in this way, the HttpServletRequest object is passed in! In the case of the Java events, it is passed in as a parameter. For simple events, it is added to the context, but is nonetheless still available for us to take things from, or add things onto. In the same location as our LearningServices.xml file (${component:learning} scriptorgofbizlearninglearning) create a new file called LearningEvents.xml. To this file add one <simple-method> element inside a <simple-methods> tag: <simple-methods xsi:noNamespaceSchemaLocation="http://www.ofbiz.org/dtds/ simple-methods.xsd"> <simple-method method-name="simpleEventTest" short-description="Testing a simple Event"> <log level="info" message="Called the Event: simpleEventTest"/> </simple-method> </simple-methods> Finally, we need to add a request-map to the controller from where this event will be invoked: <request-map uri="SimpleEventTest"> <security auth=true»https=true/> <event type=»simple»path=»org/ofbiz/learning/learning/ LearningEvents.xml»invoke=»simpleEventTest»/> <response name=»success»type=»view»value=»SimplestScreen»/> <response name=»error»type=»view»value=»SimplestScreen»/> </request-map> Notice our simple method doesn't actually do anything other than leave a message in the logs. It is with these messages that we can debug through Minilang. Validating and Converting Fields We have now met the Simple Methods Mini-Language, which is responsible for general processing to perform simple and repetitive tasks as services or events. Validation and conversion of parameters are dealt with by another type of Minilang—the Simple Map Processor. The Simple Map Processor takes values from the context Map and moves them into another Map converting them and performing validation checks en-route. Generally, Simple Map Processors will prepare the parameters passed into a simple event from an HTML form or query string. As such, the input parameters will usually be of type String. Other object types can be validated or converted using the Simple Map Processor including: BigDecimals, Doubles, Floats, Longs, Integers, Dates, Times, java.sql.Timestamps, and Booleans. The Simple Map Processors are, like simple methods, coded in XML and they adhere to the same schema (simple-methods.xsd). Open this file up again and search for The Simple Map Processor Section. The naming convention for XML files containing Simple Map Processors is to end the name of the file with MapProcs.xml (For example, LearningMapProcs.xml) and they reside in the same directory as the Simple Services and Events. One of the best examples of validation and conversion already existing in the code is to be found in the PaymentMapProcs.xml file in ${component:accounting}scriptorgofbizaccountingpayment. Open this file and find the simple-map-processor named createCreditCard. Here we can see that immediately, the field expireDate is created from the two parameters expMonth and expYear with a "/" placed in between (example, 09/2012): <make-in-string field="expireDate"> <in-field field="expMonth"/> <constant>/</constant> <in-field field="expYear"/> </make-in-string> Towards the end of the <simple-map-processor> this expireDate field is then copied into the returning Map and validated using isDateAfterToday. If the expiration date is not after today, then the card has expired and instead, a fail-message is returned. <process field="expireDate"> <copy/> <validate-method method="isDateAfterToday"> <fail-message message="The expiration date is before today"/> </validate-method> </process> The <validate-method> element uses a method called isDateAfterToday. This method is in fact a Java static method found in the class org.ofbiz.base.util.UtilValidate. We have already been using one of the OFBiz utility classes, UtilMisc, namely the toMap function, to create for us Maps from key-value pairs passed in as parameters. OFBiz provides a huge number of incredibly useful utility methods, ranging from validation, date preparation, and caching tools to String encryption and more. The framework will automatically allow Minilang access to this class. By adding a bespoke validation method into this class and recompiling, you will be able to call it from the <validate-method> in Minilang, from anywhere in your application.

Password Strength Checker Visual cues are great way to inform the user of the status of things in the application. Message boxes and alerts are used much too often for this purpose, but they usually end up irritating the user. A much smoother and enjoyable user experience is provided by subtly indicating to the user the status as an application is used. In this section, we are going to create an application that indicates the strength of a typed password to the user by the use of colors and checkboxes. We are going to use check-boxes very differently than their normal usage. This is an example of using GWT widgets in new and different ways, and mixing and matching them to provide a great user experience. Time for Action—Creating the Checker In the current day and age, passwords are required for almost everything, and choosing secure passwords is very important. There are numerous criteria suggested for creating a password that is secure from most common password cracking exploits. These criteria run the gamut from creating 15 letter passwords with a certain number of lower case and numeric digits to creating passwords using random password generators. In our example application, we are going to create a password strength checker that is very simple, and only checks the number of letters in the password. A password string that contains less than five letters will be considered weak, while a password that contains between five and seven letters will be considered to be of medium strength. Any password containing more than seven letters will be considered as strong. The criteria were deliberately kept simple so that we can focus on creating the application without getting all tangled up in the actual password strength criteria. This will help us to understand the concepts and then you can extend it to use any password strength criteria that your application warrants. This example uses a service to get the password strength, but this could also be done all on the client without needing to use a server. 1. Create a new Java file named PasswordStrengthService.java in the com.packtpub.gwtbook.samples.client package. Define a PasswordStrengthService interface with one method to retrieve the strength of a password string provided as a parameter to the method: public interface PasswordStrengthService extends RemoteService{public int checkStrength(String password);} 2. Create the asynchronous version of this service definition interface in a new Java file named PasswordStrengthServiceAsync.java in the com.packtpub.gwtbook.samples.client package : public interface PasswordStrengthServiceAsync{public void checkStrength(String password, AsyncCallback callback);} 3. Create the implementation of our password strength service in a new Java file named PasswordStrengthServiceImpl.java in the com.packtpub.gwtbook.samples.server package. public class PasswordStrengthServiceImpl extendsRemoteServiceServlet implements PasswordStrengthService{private int STRONG = 9;private int MEDIUM = 6;private int WEAK = 3;public int checkStrength(String password){if (password.length() <= 4){return WEAK;}else if (password.length() < 8){return MEDIUM;}else{return STRONG;}}} 4. Now let's create the user interface for this application. Create a new Java file named PasswordStrengthPanel.java in the com.packtpub.gwtbook.samples.client.panels package that extends the com.packtpub.gwtbook.samples.client.panels.SamplePanel class. Create a text box for entering the password string an ArrayList named strengthPanel for holding the checkboxes that we will use for displaying the strength of the password. Also create the PasswordStrengthService object. public TextBox passwordText = new TextBox();final PasswordStrengthServiceAsync pwStrengthService =(PasswordStrengthServiceAsync)GWT.create(PasswordStrengthService.class);public ArrayList strength = new ArrayList(); 5. Add a private method for clearing all the checkboxes by setting their style to the default style. private void clearStrengthPanel(){for (Iterator iter = strength.iterator(); iter.hasNext();){((CheckBox) iter.next()).setStyleName(getPasswordStrengthStyle(0));}} 6. Add a private method that will return the CSS name, based on the password strength. This is a nice way for us to dynamically set the style for the checkbox, based on the strength. private String getPasswordStrengthStyle(int passwordStrength){if (passwordStrength == 3){return "pwStrength-Weak";}else if (passwordStrength == 6){return "pwStrength-Medium";}else if (passwordStrength == 9){return "pwStrength-Strong";}else{return "";}} 7. In the constructor for the PasswordStrengthPanel class, create a HorizontalPanel named strengthPanel, add nine checkboxes to it, and set its style. As mentioned before, the styles that we are using in the sample applications in this book are available in the file Samples.css, which is part of the source code distribution for this book. We also add these same checkboxes to the strength object, so that we can retrieve them later to set their state. These checkboxes will be used for displaying the password strength visually. Create a new VerticalPanel that we will use as the container for the widgets that we are adding to the user interface. Finally, create the service target and set its entry point. HorizontalPanel strengthPanel = new HorizontalPanel();strengthPanel.setStyleName("pwStrength-Panel");for (int i = 0; i < 9; i++){CheckBox singleBox = new CheckBox();strengthPanel.add(singleBox);strength.add(singleBox);}VerticalPanel workPanel = new VerticalPanel();ServiceDefTarget endpoint=(ServiceDefTarget) pwStrengthService;endpoint.setServiceEntryPoint(GWT.getModuleBaseURL() +"pwstrength"); 8. In the same constructor, set the style for the password text box, and add an event handler to listen for changes to the password box. passwordText.setStyleName("pwStrength-Textbox");passwordText.addKeyboardListener(new KeyboardListener(){public void onKeyDown(Widget sender, char keyCode, int modifiers){}public void onKeyPress(Widget sender, char keyCode, int modifiers){}public void onKeyUp(Widget sender, char keyCode,int modifiers){if (passwordText.getText().length() > 0){AsyncCallback callback = new AsyncCallback(){public void onSuccess(Object result){clearStrengthPanel();int checkedStrength = ((Integer) result).intValue();for (int i = 0; i < checkedStrength; i++){((CheckBox) strength.get(i)).setStyleName(getPasswordStrengthStyle(checkedStrength));}}public void onFailure(Throwable caught){Window.alert("Error calling the password strengthservice." + caught.getMessage());}};pwStrengthService.checkStrength(passwordText.getText(), callback);}else{clearStrengthPanel();}}}); 9. Finally, in the constructor, add the password text box and the strength panel to the work panel. Create a little info panel that displays descriptive text about this application, so that we can display this text when this sample is selected in the list of available samples in our Samples application. Add the info panel and the work panel to a dock panel, and initialize the widget. HorizontalPanel infoPanel = new HorizontalPanel();infoPanel.add(new HTML("<div class='infoProse'>Start typing a passwordstring. The strength of the password will bechecked and displayed below. Red indicates that thepassword is Weak, Orange indicates a Mediumstrength password and Green indicates a Strongpassword. The algorithm for checking the strengthis very basic and checks the length of the passwordstring.</div>"));workPanel.add(passwordText);workPanel.add(infoPanel);workPanel.add(strengthPanel);DockPanel workPane = new DockPanel();workPane.add(infoPanel, DockPanel.NORTH);workPane.add(workPanel, DockPanel.CENTER);workPane.setCellHeight(workPanel, "100%");workPane.setCellWidth(workPanel, "100%");initWidget(workPane); 10. Add the service to the module file for the Samples application—Samples.gwt.xml in the com.packtpub.gwtbook.samples package. <servlet path="/pwstrength" class="com.packtpub.gwtbook.samples.server.PasswordStrengthServiceImpl"/> Here is the user interface for the password strength checking application: Now start typing a password string to check its strength. Here is the password strength when you type a password string that is less than five characters: What Just Happened? The password strength service checks the size of the provided string and returns an integer value of three, six, or nine based on whether it is weak, medium, or strong. It makes this determination by using the criteria that if the password string is less than five characters in length, it is weak, and if it is more than five characters but not greater than seven characters, it is considered a medium strength password. Anything over seven characters is considered to be a strong password. The user interface consists of a text box for entering a password string and a panel containing nine checkboxes that visually displays the strength of the typed string as a password. An event handler is registered to listen for keyboard events generated by the password text box. Whenever the password text changes, which happens when we type into the field or change a character in the field, we communicate asynchronously with the password strength service and retrieve the strength of the given string as a password. The returned strength is displayed to the user in a visual fashion by the use of colors to symbolize the three different password strengths. The password strength is displayed in a compound widget that is created by adding nine checkboxes to a HorizontalPanel. The color of the checkboxes is changed using CSS depending on the strength of the password string. This process of combining the basic widgets provided by GWT into more complex widgets to build user interfaces is a common pattern in building GWT applications. It is possible to build quite intricate user interfaces in this way by utilizing the power of the GWT framework. Summary In the current day and age, passwords are required for almost everything, and choosing secure passwords is very important. In this article, we implemented a password strength checker in Google Web Toolkit (GWT) and AJAX. By going through the article, the reader can also get a general idea of implementing other interactive user forms.

In this article, we will discuss the following topics: Need for Java Business Integration (JBI) Enterprise Service Bus Normalized Message Router Service Engines in NetBeans Need for Java Business Integration (JBI) To have a good understanding of Service Engines (a specific type of JBI component), we need to first understand the reason for Java Business Integration. In the business world, not all systems talk the same language. They use different protocols and different forms of communications. Legacy systems in particular can use proprietary protocols for external communication. The advent and acceptance of XML has been greatly beneficial in allowing systems to be easily integrated, but XML itself is not the complete solution. When some systems were first developed, they were not envisioned to be able to communicate with many other systems; they were developed with closed interfaces using closed protocols. This, of course, is fine for the system developer, but makes system integration very difficult. This closed and proprietary nature of enterprise systems makes integration between enterprise applications very difficult. To allow enterprise systems to effectively communicate between each other, system integrators would use vendor-supplied APIs and data formats or agree on common exchange mechanisms between their systems. This is fine for small short term integration, but quickly becomes unproductive as the number of enterprise applications to integrate gets larger. The following figure shows the problems with traditional integration. As we can see in the figure, each third party system that we want to integrate with uses a different protocol. As a system integrator, we potentially have to learn new technologies and new APIs for each system we wish to integrate with. If there are only two or three systems to integrate with, this is not really too much of a problem. However, the more systems we wish to integrate with, the more proprietary code we have to learn and integration with other systems quickly becomes a large problem. To try and overcome these problems, the Enterprise Application Integration (EAI) server was introduced. This concept has an integration server acting as a central hub. The EAI server traditionally has proprietary links to third party systems, so the application integrator only has to learn one API (the EAI server vendors). With this architecture however, there are still several drawbacks. The central hub can quickly become a bottleneck, and because of the hub-and-spoke architecture, any problems at the hub are rapidly manifested at all the clients. Enterprise Service Bus To help solve this problem, leading companies in the integration community (led by Sun Microsystems) proposed the Java Business Integration Specification Request (JSR 208) (Full details of the JSR can be found at http://jcp.org/en/jsr/detail?id=208). JSR 208 proposed a standard framework for business integration by providing a standard set of service provider interfaces (SPIs) to help alleviate the problems experienced with Enterprise Application Integration. The standard framework described in JSR 208 allows pluggable components to be added into a standard architecture and provides a standard common mechanism for each of these components to communicate with each other based upon WSDL. The pluggable nature of the framework described by JSR 208 is depicted in the following figure. It shows us the concept of an Enterprise Service Bus and introduces us to the Service Engine (SE) component: JSR 208 describes a service engine as a component, which provides business logic and transformation services to other components, as well as consuming such services. SEs can integrate Java-based applications (and other resources), or applications with available Java APIs. Service Engine is a component which provides (and consumes) business logic and transformation services to other components. There are various Service Engines available, such as the BPEL service engine for orchestrating business processes, or the Java EE service engine for consuming Java EE Web Services. The Normalized Message Router As we can see from the previous figure, SE's don't communicate directly with each other or with the clients, instead they communicate via the NMR. This is one of the key concepts of JBI, in that it promotes loose coupling of services. So, what is NMR and what is its purpose? NMR is responsible for taking messages from clients and routing them to the appropriate Service Engines for processing. (This is not strictly true as there is another standard JBI component called the Binding Component responsible for receiving client messages. Again, this further enhances the support for loose coupling within JBI, as Service Engines are decoupled from their transport infrastructure). NMR is responsible for passing normalized (that is based upon WSDL) messages between JBI components. Messages typically consist of a payload and a message header which contains any other message data required for the Service Engine to understand and process the message (for example, security information). Again, we can see that this provides a loosely coupled model in which Service Engines have no prior knowledge of other Service Engines. This therefore allows the JBI architecture to be flexible, and allows different component vendors to develop standard based components. Normalized Message Router enables technology for allowing messages to be passed between loosely coupled services such as Service Engines. The figure below gives an overview of the message routing between a client application and two service engines, in this case the EE and SQL service engines. In this figure, a request is made from the client to the JBI Container. This request is passed via NMR to the EE Service Engine. The EE Service Engine then makes a request to the SQL Service Engine via NMR. The SQL Service Engine returns a message to the EE Service Engine again via NMR. Finally, the message is routed back to the client through NMR and JBI framework. The important concept here is that NMR is a message routing hub not only between clients and service engines, but also for intra-communication between different service engines. The entire architecture we have discussed is typically referred to as an Enterprise Service Bus. Enterprise Service Bus (ESB) is a standard-based middleware architecture that allows pluggable components to communicate with each other via a messaging subsystem.

This application supports the single document interface, which implies that we have one document class object and one view class object. The other applications support the multiple document interface, they have one document class object and zero or more view class objects. The following screenshot depicts a classic example of the Tetris Application: We start by generating the application's skeleton code with The Application Wizard. The process is similar to the Ring application code. There is a small class Square holding the position of one square and a class ColorGrid managing the game grid. The document class manages the data of the game and handles the active (falling down) figure and the next (shown to the right of the game grid) figure. The view class accepts input from the keyboard and draws the figures and the game grid. The Figure class manages a single figure. It is responsible for movements and rotations. There are seven kinds of figures. The Figure Info files store information pertaining to their colors and shapes. The Tetris Files We start by creating a MFC application with the name Tetris and follow the steps of the Ring application. The classes CTetrisApp, CMainFrame, CTetrisDoc, CTetrisView, and CAboutDlg are then created and added to the project. There are only two differences. We need to state that we are dealing with a "Single Document Application Type", that the file extension is "Trs" and that the file type long name is "A Game of Tetris". Otherwise, we just accept the default settings. Note that in this application we accept the CView base class instead of the CScrollView like we did in the Ring application.     We add the marked lines below. In all other respects, we leave the file unmodified. We will not need to modify the files Tetris.h, MainFrm.h, MainFrm.cpp, StdAfx.h, StdAfx.cpp, Resource.h, and Tetris.rc. #include"stdafx.h"#include "Square.h"#include"Figure.h"#include "ColorGrid.h"#include"Tetris.h"#include "MainFrm.h"#include"TetrisDoc.h"#include "TetrisView.h"//... The Color Grid Class The ColorGrid handles the background game grid of twenty rows and twenty columns. Each square can have a color. At the beginning, every square is initialized to the default color white. The Index method is overloaded with a constant version that returns the color of the given square, and a non-constant version that returns a reference to the color. The latter version makes it possible to change the color of a square. ColorGrid.h classSquare{public:Square();Square(int iRow, int iCol);int Row() const {return m_iRow;}int Col() const {return m_iCol;}private:int m_iRow, m_iCol;}; There are two Index methods, the second one is intended to be called on a constant object. Both methods check that the given row and position have valid values. The checks are, however, for debugging purposes only. The methods are always called with valid values. Do not forget to include the file StdAfx.h. ColorGrid.cpp const int ROWS = 20;const int COLS = 10;classColorGrid{public:ColorGrid();void Clear();COLORREF&Index(int iRow, int iCol);const COLORREF Index(int iRow, int iCol)const;void Serialize(CArchive&archive);private:COLORREF m_buffer[ROWS * COLS];}; The Document Class CTetrisDoc is the document class of this application. When created, it overrides OnNewDocument and Serialize from its base class CDocument. We add to the CTetrisDoc class a number of fields and methods. The field m_activeFigure is active figure, that is the one falling down during the game. The field m_nextFigure is the next figure, that is the one showed in the right part of the game view. They both are copies of the objects in the m_figureArray, which is an array figure object. There is one figure object of each kind (one figure of each color). The integer list m_scoreList holds the ten top list of the game. It is loaded from the file ScoreList.txt by the constructor and saved by the destructor. The integer field m_iScore holds the score of the current game. GetScore, GetScoreList, GetActiveFigure, GetNextFigure, and GetGrid are called by the view class in order to draw the game grid. They simply return the values of the corresponding fields. The field m_colorGrid is an object of the class ColorGrid, which we defined in the previous section. It is actually just a matrix holding the colors of the squares of the game grid. Each square is intialized to the color white and a square is considered to be empty as long as it is white. When the application starts, the constructor calls the C standard library function srand. The name is an abbreviation for sowing a random seed. By calling srand with an integer seed, it will generate a series of random number. In order to find a new seed every time the application starts, the C standard library function time is called, which returns the number of seconds elapsed since January 1, 1970. In order to obtain the actual random number, we call rand that returns a number in the interval from zero to the predefined constant RAND_MAX. The prototypes for these functions are defined in time.h (time) and stdlib.h (rand and srand), respectively. #include"StdAfx.h"COLORREF& ColorGrid::Index(int iRow, int iCol){check((iRow >= 0) && (iRow < ROWS));check((iCol >= 0) && (iCol < COLS));return m_buffer[iRow * COLS + iCol];}const COLORREF ColorGrid::Index(int iRow, int iCol)const{check((iRow >= 0) && (iRow < ROWS));check((iCol >= 0) && (iCol < COLS));return m_buffer[iRow * COLS + iCol];} When the user presses the space key and the active figure falls down or when a row is filled and is flashed, we have to slow down the process in order for the user to apprehand the event. There is a Win32 API function Sleep that pauses the application for the given amount of milliseconds. #include <time.h>#include <stdlib.h>time_ttime(time_t *pTimer);void srand(unsigned int uSeed);intrand(); The user can control the horizontal movement and rotation of the falling figures by pressing the arrow keys. Left and right arrow keys move the figure to the left or right. The up and down arrow key rotates the figure clockwise or counter clockwise, respectively. Every time the user presses one of those keys, a message is sent to the view class object and caught by the method OnKeyDown, which in turn calls one of the methods LeftArrowKey, RightArrowKey, UpArrowKey, DownArrowKey to deal with the message. They all work in a similar fashion. They try to execute the movement or rotation in question. If it works, both the old and new area of the figure is repainted by making calls to UpdateAllViews. The view class also handles a timer that sends a message every second the view is in focus. The message is caught by the view class method OnTimer that in turn calls Timer. It tries to move the active figure one step downwards. If that is possible, the area of the figure is repainted in the same way as in the methods above. However, if it is not possible, the squares of the figure are added to the game grid. The active figure is assigned to the next figure, and the next figure is assigned a copy of a randomly selected figure in m_figureArray. We also check whether any row has been filled. In that case, it will be removed and we will check to see if the game is over. The user can speed up the game by pressing the space key. The message is caught and sent to SpaceKey. It simply calls OnTimer as many times as possible at intervals of twenty milliseconds in order to make the movement visible to the user. When a figure has reached its end position and any full rows have been removed, the figure must be valid. That is, its squares are not allowed to occupy any already colored position. If it does, the game is over and GameOver is called. It starts by making the game grid gray and asks the users whether they want to play another game. If they do, the game grid is cleared and set back to colored mode and a new game starts. If they do not, the application exits. NewGame informs the players whether they made to the top ten list and inquires about another game by displaying a message box. AddToScore examines whether the player has made to the ten top list. If so, the score is added to the list and the ranking is returned, if not, zero is returned. DeleteFullRows traverses the game grid from top to bottom flashing and removing every full row. IsRowFull traverses the given row and returns true if no square has the default color (white). FlashRow flashes the row by showing it three times in grayscale and color at intervals of twenty milliseconds. DeleteRow removes the row by moving all rows above one step downwards and inserting an empty row (all white squares) at top. The next figure and the current high score are painted at specific positions on the client area, the rectangle constants NEXT_AREA and SCORE_AREA keep track of those positions. TetrisDoc.h void Sleep(int iMilliSeconds); The field m_figureArray holds seven figure objects, one of each color. When we need a new figure, we just randomly copy one of them. TetrisDoc.cpp typedef CList<int>IntList;const int FIGURE_ARRAY_SIZE = 7;class CTetrisDoc :publicCDocument{protected:CTetrisDoc();public:virtual ~CTetrisDoc();void SaveScoreList();protected:DECLARE_MESSAGE_MAP()DECLARE_DYNCREATE(CTetrisDoc)public:virtual void Serialize(CArchive& archive);int GetScore() const {return m_iScore;}const IntList* GetScoreList() {return &m_scoreList;}const ColorGrid* GetGrid() {return &m_colorGrid;}const Figure& GetActiveFigure() const{return m_activeFigure;}const Figure& GetNextFigure() const {return m_nextFigure;}public:void LeftArrowKey();void RightArrowKey();void UpArrowKey();void DownArrowKey();BOOL Timer();void SpaceKey();private:void GameOver();BOOL NewGame();int AddScoreToList();void DeleteFullRows();BOOL IsRowFull(int iRow);void FlashRow(int iFlashRow);void DeleteRow(int iDeleteRow);private:ColorGrid m_colorGrid;Figure m_activeFigure, m_nextFigure;int m_iScore;IntList m_scoreList;const CRect NEXT_AREA, SCORE_AREA;static Figure m_figureArray[FIGURE_ARRAY_SIZE];}; When the user presses the left arrow key, the view class object catches the message and calls LeftArrowKey in the document class object. We try to move the active figure one step to the left. It is not for sure that we succeed. The figure may already be located at the left part of the game grid. However, if the movement succeeds, the figure's position is repainted and true is returned. In that case, we repaint the figure's old and new graphic areas in order to repaint the figure. Finally, we set the modified flag since the figure has been moved. The method RightArrowKey works in a similar way. Figure redFigure(NORTH, RED, RedInfo);Figure brownFigure(EAST, BROWN, BrownInfo);Figure turquoiseFigure(EAST, TURQUOISE, TurquoiseInfo);Figure greenFigure(EAST, GREEN, GreenInfo);Figure blueFigure(SOUTH, BLUE, BlueInfo);Figure purpleFigure(SOUTH, PURPLE, PurpleInfo);Figure yellowFigure(SOUTH, YELLOW, YellowInfo);Figure CTetrisDoc::m_figureArray[] = {redFigure, brownFigure, turquoiseFigure, greenFigure, yellowFigure, blueFigure, purpleFigure}; Timer is called every time the active figure is to moved one step downwards. That is,each second when the application has focus. If the downwards movement succeeds, then the figure is repainted in a way similar to LeftArrowKey above. However, if the movement does not succeed, the movement of the active figure has come to an end. We call AddToGrid to color the squares of the figure. Then we copy the next figure to the active figure and randomly copy a new next figure. The next figure is the one shown to the right of the game grid. However, the case may occur that the game grid is full. That is the case if the new active figure is not valid, that is, the squares occupied by the figure are not free. If so, the game is over, and the user is asked whether he wants a new game. void CTetrisDoc::LeftArrowKey(){CRectrcOldArea = m_activeFigure.GetArea();if (m_activeFigure.MoveLeft()){CRectrcNewArea = m_activeFigure.GetArea();UpdateAllViews(NULL, COLOR, (CObject*) &rcOldArea);UpdateAllViews(NULL, COLOR, (CObject*) &rcNewArea);SetModifiedFlag();}} If the user presses the space key, the active figure falling will fall faster. The Timer method is called every 20 milliseconds.   BOOLCTetrisDoc::Timer(){SetModifiedFlag();CRectrcOldArea = m_activeFigure.GetArea();if (m_activeFigure.MoveDown()){CRectrcNewArea = m_activeFigure.GetArea();UpdateAllViews(NULL, COLOR, (CObject*) &rcOldArea);UpdateAllViews(NULL, COLOR, (CObject*) &rcNewArea);returnTRUE;}else{m_activeFigure.AddToGrid();m_activeFigure = m_nextFigure;CRect rcActiveArea = m_activeFigure.GetArea();UpdateAllViews(NULL, COLOR, (CObject*) &rcActiveArea);m_nextFigure = m_figureArray[rand() % FIGURE_ARRAY_SIZE];UpdateAllViews(NULL, COLOR, (CObject*) &NEXT_AREA);DeleteFullRows();if (!m_activeFigure.IsFigureValid()){GameOver();}returnFALSE;}} When the game is over, the users are asked whether they want a new game. If so, we clear the grid, randomly select the the next active and next figure, and repaint the whole client area. void CTetrisDoc::SpaceKey(){while(Timer()){Sleep(20);}} Each time a figure is moved, one or more rows may be filled. We start by checking the top row and then go through the rows downwards. For each full row, we first flash it and then remove it. voidCTetrisDoc::GameOver(){UpdateAllViews(NULL, GRAY);if (NewGame()){m_colorGrid.Clear();m_activeFigure = m_figureArray[rand() %FIGURE_ARRAY_SIZE];m_nextFigure = m_figureArray[rand() % FIGURE_ARRAY_SIZE];UpdateAllViews(NULL, COLOR);else{SaveScoreList();exit(0);}} When a row is completely filled, it will flash before it is removed. The flash effect is executed by redrawing the row in color and in grayscale three times with an interval of 50 milliseconds. void CTetrisDoc::DeleteFullRows(){int iRow = ROWS - 1;while (iRow >= 0){if(IsRowFull(iRow)){FlashRow(iRow);DeleteRow(iRow);++m_iScore;UpdateAllViews(NULL, COLOR, (CObject*) &SCORE_AREA);}else{--iRow;}}} When a row is removed, we do not really remove it. If we did, the game grid would shrink. Instead, we copy the squares above it and clear the top row. voidCTetrisDoc::FlashRow(int iRow){for (int iCount = 0; iCount < 3; ++iCount){CRect rcRowArea(0, iRow, COLS, iRow + 1);UpdateAllViews(NULL, GRAY, (CObject*) &rcRowArea);Sleep(50);CRect rcRowArea2(0, iRow, COLS, iRow + 1);UpdateAllViews(NULL, COLOR, (CObject*) &rcRowArea2);Sleep(50);}} The View Class CTetrisView is the view class of the application. It receives system messages and (completely or partly) redraws the client area. The field m_iColorStatus holds the painting status of the view. Its status can be either color or grayscale. The color status is the normal mode, m_iColorStatus is initialized to color in the constructor. The grayscale is used to flash rows and to set the game grid in grayscale while asking the user for another game. OnCreate is called after the view has been created but before it is shown. The field m_pTetrisDoc is set to point at the document class object. It is also confirmed to be valid. OnSize is called each time the size of the view is changed. It sets the global variables g_iRowHeight and g_iColWidth (defi ned in Figure.h), which are used by method of the Figure and ColorGrid classes to paint the squares of the figures and the grid. OnSetFocus and OnKillFocus are called when the view receives and loses the input focus. Its task is to handle the timer. The idea is that the timer shall continue to send timer messages every second as long as the view has the input focus. Therefore, OnSetFocus sets the timer and OnKillFocus kills it. This arrangement implies that OnTimer is called each second the view has input focus. In Windows, the timer cannot be turned off temporarily; instead, we have to set and kill it. The base class of the view, CWnd, has two methods: SetTimer that initializes a timer and KillTimer that stops the timer. The first parameter is a unique identifier to distinguish this particular timer from any other one. The second parameter gives the time interval of the timer, in milliseconds. When we send a null pointer as the third parameter, the timer message will be sent to the view and caught by OnTimer. KillTimer simply takes the identity of the timer to finish. void CTetrisDoc::DeleteRow(int iMarkedRow){for (int iRow = iMarkedRow; iRow > 0; --iRow){for (int iCol = 0; iCol < COLS; ++iCol){m_colorGrid.Index(iRow, iCol) = m_colorGrid.Index(iRow - 1, iCol);}}for (int iCol = 0; iCol < COLS; ++iCol){m_colorGrid.Index(0, iCol) = WHITE;}CRect rcArea(0, 0, COLS, iMarkedRow + 1);UpdateAllViews(NULL, COLOR, (CObject*) &rcArea);} OnKeyDown is called every time the user presses a key on the keyboard. It analizes the pressed key and calls suitable methods in the document class if the left, right, up, or down arrow key or the space key is pressed. When a method of the document class calls UpdateAllViews, OnUpdate of the view class object connected to the document object is called. As this is a single view application, the application has only one view object on which OnUpdate is called. UpdateAllViews takes two extra parameters, hints, which are sent to OnUpdate. The first hint tells us whether the next repainting shall be done in color or in grayscale, the second hint is a pointer to a rectangle holding the area that is to be repainted. If the pointer is not null, we calculate the area and repaint it. If it is null, the whole client area is repainted. OnUpdate is also called by OnInitialUpdate of the base class CView with both hints set to zero. That is not a problem because the COLOR constant is set to zero. The effect of this call is that the whole view is painted in color. OnUpdate calls UpdateWindow in CView that in turn calls OnPaint and OnDraw with a device context. OnPaint is also called by the system when the view (partly or completely) needs to be repainted. OnDraw loads the device context with a black pen and then draws the grid, the score list, and´the active and next figures. TetrisView.h UINT_PTR SetTimer(UINT_PTR iIDEvent, UINT iElapse, void (CALLBACK* lpfnTimer)(HWND, UINT, UINT_PTR, DWORD));BOOL KillTimer(UINT_PTR nIDEvent); TetrisView.cpp This application catches the messsages WM_CREATE, WM_SIZE, WM_SETFOCUS, WM_KILLFOCUS, WM_TIMER, and WM_KEYDOWN. const intTIMER_ID = 0;enum {COLOR = 0, GRAY = 1};class CTetrisDoc;COLORREF GrayScale(COLORREF rfColor);class CTetrisView : public CView{protected: CTetrisView();DECLARE_DYNCREATE(CTetrisView)DECLARE_MESSAGE_MAP()public: afx_msgint OnCreate(LPCREATESTRUCT lpCreateStruct);afx_msg void OnSize(UINT nType, int iClientWidth, int iClientHeight);afx_msg void OnSetFocus(CWnd* pOldWnd);afx_msg void OnKillFocus(CWnd* pNewWnd);afx_msg void OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags);afx_msg void OnTimer(UINT nIDEvent);void OnUpdate(CView* /* pSender */, LPARAM lHint, CObject* pHint);void OnDraw(CDC* pDC); private: void DrawGrid(CDC* pDC);void DrawScoreAndScoreList(CDC* pDC);void DrawActiveAndNextFigure(CDC* pDC);private: CTetrisDoc* m_pTetrisDoc;int m_iColorStatus;}; When the view object is created, is connected to the document object by the pointer m_pTetrisDoc. BEGIN_MESSAGE_MAP(CTetrisView, CView)ON_WM_CREATE()ON_WM_SIZE()ON_WM_SETFOCUS()ON_WM_KILLFOCUS()ON_WM_TIMER()ON_WM_KEYDOWN()END_MESSAGE_MAP() The game grid is dimensioned by the constants ROWS and COLS. Each time the user changes the size of the application window, the global variables g_iRowHeight and g_iColWidth, which are defined in Figure.h, store the height and width of one square in pixels. int CTetrisView::OnCreate(LPCREATESTRUCT lpCreateStruct){// We check that the view has been correctly created.if (CView::OnCreate(lpCreateStruct) == -1){return -1;}m_pTetrisDoc = (CTetrisDoc*) m_pDocument;check(m_pTetrisDoc != NULL);ASSERT_VALID(m_pTetrisDoc);return 0;} OnUpdate is called by the system when the window needs to be (partly or completely) repainted. In that case, the parameter pHint is zero and the whole client area is repainted. However, this method is also indirectly called when the document class calls UpdateAllView. In that case, lHint has the value color or gray, depending on whether the client area shall be repainted in color or in a grayscale. If pHint is non-zero, it stores the coordinates of the area to be repainted. The coordinates are given in grid coordinates that have to be translated into pixel coordinates before the area is invalidated. The method first calls Invalidate or InvalidateRect to define the area to be repainted, then the call to UpdateWindow does the actual repainting by calling OnPaint in CView, which in turn calls OnDraw below. void CTetrisView::OnSize(UINT /* uType */,int iClientWidth, int iClientHeight){g_iRowHeight = iClientHeight / ROWS;g_iColWidth = (iClientWidth / 2) / COLS;} OnDraw is called when the client area needs to be repainted, by the system or by UpdateWindow in OnUpdate. It draws a vertical line in the middle of the client area, and then draws the game grid, the high score list, and the current figures. voidCTetrisView::OnUpdate(CView* /* pSender */, LPARAM lHint, CObject*pHint){m_iColorStatus = (int) lHint;if (pHint != NULL){CRect rcArea = *(CRect*) pHint;rcArea.left *= g_iColWidth;rcArea.right *= g_iColWidth;rcArea.top *= g_iRowHeight;rcArea.bottom *= g_iRowHeight;InvalidateRect(&rcArea);}else{Invalidate();}UpdateWindow();} DrawGrid traverses through the game grid and paints each non-white square. If a square is not occupied, it has the color white and it not painted. The field m_iColorStatus decides whether the game grid shall be painted in color or in grayscale. void CTetrisView::OnDraw(CDC* pDC){CPen pen(PS_SOLID, 0, BLACK);CPen* pOldPen = pDC->SelectObject(&pen);pDC->MoveTo(COLS * g_iColWidth, 0);pDC->LineTo(COLS * g_iColWidth, ROWS * g_iRowHeight);DrawGrid(pDC);DrawScoreAndScoreList(pDC);DrawActiveAndNextFigure(pDC);pDC->SelectObject(&pOldPen);} GrayScale returns the grayscale of the given color, which is obtained by mixing the average of the red, blue, and green component of the color. voidCTetrisView::DrawGrid(CDC* pDC){const ColorGrid* pGrid = m_pTetrisDoc->GetGrid();for (int iRow = 0; iRow < ROWS; ++iRow){for (int iCol = 0; iCol < COLS; ++iCol){ COLORREF rfColor = pGrid->Index(iRow, iCol);if (rfColor != WHITE){CBrushbrush((m_iColorStatus == COLOR) ? rfColor:GrayScale(rfColor));CBrush* pOldBrush = pDC->SelectObject(&brush);DrawSquare(iRow, iCol, pDC);pDC->SelectObject(pOldBrush);}}}} The active figure (m_activeFigure) is the figure falling down on the game grid.The next figure (m_nextFigure) is the figure announced at the right side of the client area. In order for it to be painted at the right-hand side, we alter the origin to the middle of the client area, and one row under the upper border by calling SetWindowOrg.

To keep things simple though, the article doesn’t discuss how to implement database-backed web pages with Python, concentrating only on how to connect Python with MySQL. Sample Application The best way to learn new programming techniques is to write an application that exercises them. This article will walk you through the process of building a simple Python application that interacts with a MySQL database. In a nutshell, the application picks up some live data from a web site and then persists it to an underlying MySQL database. For the sake of simplicity, it doesn’t deal with a large dataset. Rather, it picks up a small subset of data, storing it as a few rows in the underlying database. In particular, the application gets the latest post from the Packt Book Feed page available at http://feeds.feedburner.com/packtpub/sDsa?format=xml. Then, it analyzes the post’s title, finding appropriate tags for the article associated with the post, and finally inserts information about the post into the posts and posttags underlying database tables. As you might guess, a single post may be associated with more than one tag, meaning a record in the posts table may be related to several records in the posttags table. Diagrammatically, the sample application components and their interactions might look like this: Note the use of appsample.py. This script file will contain all the application code written in Python. In particular, it will contain the list of tags, as well as several Python functions packaging application logic. Software Components To build the sample discussed in the article you’re going to need the following software components installed on your computer: Python 2.5.x MySQLdb 1.2.x MySQL 5.1 All these software components can be downloaded and used for free. Although you may already have these pieces of software installed on your computer, here’s a brief overview of where you can obtain them. You can download an appropriate Python release from the Downloads page at Python’s web site at http://python.org/download/. You may be tempted to download the most recent release. Before you choose the release, however, it is recommended that you visit the Python for MySQL page at http://sourceforge.net/projects/mysql-python/ to check what Python releases are supported by the current MySQLdb module that will be used to connect your Python installation with MySQL. MySQLdb is the Python DB API-2.0 interface for MySQL. You can pick up the latest MySQLdb package (version 1.2.2 at the time of writing) from the sourceforge.net’s Python for MySQL page at http://sourceforge.net/projects/mysql-python/. Before you can install it, though, make sure you have Python installed in your system. You can obtain the MySQL 5.1 distribution from the mysql.com web site at http://dev.mysql.com/downloads/mysql/5.1.html, picking up the package designed for your operating system. Setting up the Database Assuming you have all the software components that were outlined in the preceding section installed in your system, you can now start building the sample application. The first step is to create the posts and posttags tables in your underlying MySQL database. As mentioned earlier, a single post may be associated with more than one tag. What this means in practice is that the posts and posttags tables should have a foreign key relationship. In particular, you might create these tables as follows: CREATE TABLE posts ( title VARCHAR(256) PRIMARY KEY, guid VARCHAR(1000), pubDate VARCHAR(50) ) ENGINE = InnoDB; CREATE TABLE posttags ( title VARCHAR(256), tag VARCHAR(20), PRIMARY KEY(title,tag), FOREIGN KEY(title) REFERENCES posts(title) ) ENGINE = InnoDB; As you might guess, you don’t need to populate above tables with data now. This will be automatically done later when you launch the sample. Developing the Script Now that you have the underlying database ready, you can move on and develop the Python code to complete the sample. In particular, you’re going to need to write the following components in Python: tags nested list of tags that will be used to describe the posts obtained from the Packt Book Feed page. obtainPost function that will be used to obtain the information about the latest post from the Packt Book Feed page. determineTags function that will determine appropriate tags to be applied to the latest post obtained from the Packt Book Feed page. insertPost function that will insert the information about the post obtained into the underlying database tables: posts and posttags. execPr function that will make calls to the other, described above functions. You will call this function to launch the application. All the above components will reside in a single file, say, appsample.py that you can create in your favorite text editor, such as vi or Notepad. First, add the following import declarations to appsample.py: import MySQLdb import urllib2 import xml.dom.minidom As you might guess, the first module is required to connect Python with MySQL, providing the Python DB API-2.0 interface for MySQL. The other two are needed to obtain and then parse the Packt Book Feed page’s data. You will see them in action in the obtainPost function in a moment. But first let’s create a nested list of tags that will be used by the determineTags function that determines the tags appropriate for the post being analyzed. To save space here, the following list contains just a few tags. You may and should include more tags to this list, of course. tags=["Python","Java","Drupal","MySQL","Oracle","Open Source"] The next step is to add the obtainPost function responsible for getting the data from the Packt Book Feed page and generating the post dictionary that will be utilized in further processing: def obtainPost(): addr = "http://feeds.feedburner.com/packtpub/sDsa?format=xml" xmldoc = xml.dom.minidom.parseString(urllib2.urlopen(addr).read()) item = xmldoc.getElementsByTagName("item")[0] title = item.getElementsByTagName("title")[0].firstChild.data guid = item.getElementsByTagName("guid")[0].firstChild.data pubDate = item.getElementsByTagName("pubDate")[0].firstChild.data post ={"title": title, "guid": guid, "pubDate": pubDate} return post Now that you have obtained all the required information about the latest post on the Packt Book Feed page, you can analyze the post’s title to determine appropriate tags. For that, add the determineTags function to appsample.py: def determineTags(title, tagslist): curtags=[] for curtag in tagslist: if title.find(curtag)>-1:curtags.append(curtag) return curtags By now, you have both the post and tags to be persisted to the database. So, add the insertPost function that will handle this task (don’t forget to change the parameters specified to the MySQLdb.connect function for the actual ones): def insertPost(title, guid, pubDate, curtags): db=MySQLdb.connect(host="localhost",user="usrsample",passwd="pswd",db="dbsample") c=db.cursor() c.execute("""INSERT INTO posts (title, guid, pubDate) VALUES(%s, %s,%s)""", (title, guid, pubDate)) db.commit() for tag in curtags: c.execute("""INSERT INTO posttags (title, tag) VALUES(%s,%s)""", (title, tag)) db.commit() db.close() All that is left to do is add the execPr function that brings all the pieces together, calling the above functions in the proper order: def execPr(): p = obtainPost() t = determineTags(p["title"],tags) insertPost(p["title"], p["guid"], p["pubDate"], t) Now let’s test the code we just wrote. The simplest way to do this is through Python’s interactive command line. To start an interactive Python session, you can type python at your system shell prompt. It’s important to realize that since the sample discussed here is going to obtain some data from the web, you must connect to the Internet before you launch the application. Once you’re connected, you can launch the execPr function in your Python session, as follows: >>>import appsample >>>appsample.execPr() If everything is okay, you should see no messages. To make sure that everything really went as planned, you can check the posts and posttags tables. To do this, you might connect to the database with the MySQL command-line tool and then issue the following SQL commands: SELECT * FROM posts; The above should generate the output that might look like this: |title |guid |pubDate ------------------------------------------------------------------ Open Source CMS Award Voting Now Closed | http://www.packtpub.com/ article/2008-award-voting-closed | Tue, 21 Oct 2008 09:29:54 +0100 Then, you might want to check out the posttags table: SELECT * FROM posttags; This might generate the following output: |title |tag Open Source CMS Award Voting Now Closed | Open Source Please note that you may see different results since you are working with live data. Another thing to note here is that if you want to re-run the sample, you first need to empty the posts and posttags tables. Otherwise, you will encounter the problem related to the primary key constraints. However, that won’t be a problem at all if you re-run the sample in a few days, when a new post or posts appear on the Packt Book Feed page. Conclusion In this article you looked at a simple Python application persisting data to an underlying MySQL database. Although, for the sake of simplicity, the sample discussed here doesn’t offer a web interface, it illustrates how you can obtain data from the Internet, and then utilize it within your application, and finally store that data in the database.

Configuring Printer Classes By default there are no printer classes set up. You will need to define them. The following are some of the criteria you can use to define printer classes: Printer Type: Printer type can be a PostScript or non-PostScript printer. Location: The location can describe the printer's place; for example the printer is placed on the third floor of the building. Department: Printer classes can also be defined on the basis of the department to which the printer belongs. The printer class might contain several printers that are used in a particular order. CUPS always checks for an available printer in the order in which printers were added to a class. Therefore, if you want a high-speed printer to be accessed first, you would add the high-speed printer to the class before you add a low-speed printer. This way, the high-speed printer can handle as many print requests as possible, and the low-speed printer would be reserved as a backup printer when the high-speed printer is in use. It is not compulsory to add printers in classes. There are a few important tasks that you need to do to manage and configure printer classes. Printer classes can themselves be members of other classes. So it is possible for you to define printer classes for high availability for printing. Once you configure the printer class, you can print to the printer class in the same way that you print to a single printer. Features and Advantages Here are some of the features and advantages of printer classes in CUPS: Even if a printer is a member of a class, it can still be accessed directly by users if you allow it. However, you can make individual printers reject jobs while groups accept them. As the system administrator, you have control over how printers in classes can be used. The replacement of printers within the class can easily be done. Let's understand this with the help of an example. You have a network consisting of seven computers running Linux, all having CUPS installed. You want to change printers assigned to the class. You can remove a printer and add a new one to the class in less than a minute. The entire configuration required is done as all other computers get their default printing routes updated in another 30 seconds. It takes less than one minute for the whole change—less time than a laser printer takes to warm up. A company is having the following type of printers with their policy as: A class for B/W laser printers that anybody can print on A class for draft color printers that anybody can print on, but with restrictions on volume A class for precision color printers that is unblocked only under the administrator's supervision CUPS provide the means for centralizing printers, and users will only have to look for a printer in a single place It provides the means for printing on another Ethernet segment without allowing normal Windows to broadcast traffic to get across and clutter up the network bandwidth It makes sure that the person printing from his desk on the second floor of the other building doesn't get stuck because the departmental printer on the ground floor of this building has run out of paper and his print job has got redirected to the standby printer All of these printers hang off Windows machines, and would be available directly for other computers running under Windows. However, we get the following advantages by providing them through CUPS on a central router: Implicit Class CUPS also supports the special type of printer class called as implicit class. These implicit classes work just like printer classes, but they are created automatically based on the available "printers and printer classes" on the network. CUPS identifies printers with identical configurations intelligently, and has the client machines send their print jobs to the first available printer. If one or more printers go down, the jobs are automatically redirected to the servers that are running, providing fail-safe printing. Managing Printer Classes Through Command-Line You can perform this task only by using the lpadmin -c command. Jobs sent to a printer class are forwarded to the first available printer in the printer class. Adding a Printer to a Class You can run the following command with the –p and -c options to add a printer to a class: $sudo lpadmin –p cupsprinter –c cupsclass The above example shows that the printer cupsprinter has been added to printer class cupsclass: You can verify whether the printers are in a printer class: $lpstat -c cupsclass Removing a Printer from a Class You need to run lpadmin command with –p and –r options to remove printer from a class. If all the printers from a class are removed, then that class can get deleted automatically. $sudo lpadmin –p cupsprinter –r cupsclass The above example shows that the printer cupsprinter has been removed from the printer class, cupsclass: Removing a Class To remove a class, you can run the lpadmin command with the –x option: $sudo lpadmin -x cupsclass The above command will remove cupsclass. Managing Printer Classes Through CUPS Web Interface Like printers, and groups of printers, printer classes can also be managed by the CUPS web interface. In the web interface, CUPS displays a tab called Classes, which has all the options to manage the printer classes. You can get this tab directly by visiting the following URL: http://localhost:631/classes If no classes are defined, then the screen will appear as follows which shows the search and sorting options: Adding a New Printer Class A printer class can be added using the Add Class option in the Administration tab. It is useful to have a helpful description in the Name field to identify your class. You can add the additional information regarding the printer class under the Description field that would be seen by users when they select this printer class for a job. The Location field can be used to help you group a set of printers logically and thus help you identify different classes. In the following figure, we are adding all black and white printers into one printer class. The Members box will be pre-populated with a list of all printers that have been added to CUPS. Select the appropriate printers for your class and it will be ready for use. Once your class is added, you can manage it using the Classes tab. Most of the options here are quite similar to the ones for managing individual printers, as CUPS treats each class as a single entity. In the Classes tab, we can see following options with each printer class: Stop Class Clicking on Stop Class changes the status of all the printers in that class to "stop". When a class is stopped, this option changes to Start Class. This changes the status of all of the printers to "idle". Now, they are once again ready to receive print jobs. Reject Jobs Clicking on Reject Jobs changes the status of all the printers in that class to "reject jobs". When a class is in this state, this option changes to Accept Jobs which changes the status of all of the printers to "accept jobs" so that they are once again ready to accept print jobs.    

The Core Database Much of the data we see in Joomla! is stored in the database. A base installation has over thirty tables. Some of these are related to core extensions and others to the inner workings of Joomla!. There is an official database schema, which describes the tables created during the installation. For more information, please refer to: http://dev.joomla.org/ component/option,com_jd-wiki/Itemid,31/id,guidelines:database/. A tabular description is available at: http://dev.joomla.org/downloads/Joomla15_DB-Schema.htm. We access the Joomla! database using the global JDatabase object. The JDatabase class is an abstract class, which is extended by different database drivers. There are currently only two database drivers included in the Joomla! core, MySQL and MySQLi. We access the global JDatabase object using JFactory: $db =& JFactory::getDBO(); Extending the Database When we create extensions, we generally want to store data in some form. If we are using the database, it is important to extend it in the correct way. Table Prefix All database tables have a prefix, normally jos_, which helps in using a single database for multiple Joomla! installations. When we write SQL queries, to accommodate the variable table prefix, we use a symbolic prefix that is substituted with the actual prefix at run time. Normally the symbolic prefix is #__, but we can specify an alternative prefix if we want to. Schema Conventions When we create tables for our extensions, we must follow some standard conventions. The most important of these is the name of the table. All tables must use the table prefix and should start with name of the extension. If the table is storing a specific entity, add the plural of the entity name to the end of the table name separated by an underscore. For example, an items table for the extension 'My Extension' would be called #__myExtension_items. Table field names should all be lowercase and use underscore word separators; you should avoid using underscores if they are not necessary. For example, you can name an email address field as email. If you had a primary and a secondary email field, you could call them email and email_secondary; there is no reason to name the primary email address email_primary. If you are using a primary key record ID, you should call the field id, make it of type integer auto_increment, and disallow null. Doing this will allow you to use the Joomla! framework more effectively. Common Fields We may use some common fields in our tables. Using these fields will enable us to take advantage of the Joomla! framework. Publishing We use publishing to determine whether to display data. Joomla! uses a special field called published, of type tinyint(1); 0 = not published, 1 = published. Hits If we want to keep track of the number of times a record has been viewed, we canuse the special field hits, of type integer and with the default value 0. Checking Out To prevent more than one user trying to edit one record at a time we can check out records (a form of software record locking). We use two fields to do this, checked_out and checked_out_time. checked_out, of type integer, holds the ID of the user that has checked out the record. checked_out_time, of type datetime, holds the date and time when the record was checked out. A null date and a user ID of 0 is recorded if the record is not checked out. Ordering We often want to allow administrators the ability to choose the order in which items appear. The ordering field, of type integer, can be used to number records sequentially to determine the order in which they are displayed. This field does not need to be unique and can be used in conjunction with WHERE clauses to form ordering groups. Parameter Fields We use a parameter field, a TEXT field normally named params, to store additional information about records; this is often used to store data that determines how a record will be displayed. The data held in these fields is encoded as INI strings (which we handle using the JParameter class). Before using a parameter field, we should carefully consider the data we intend to store in the field. Data should only be stored in a parameter field if all of the following criteria are true: Not used for sorting records Not used in searches Only exists for some records Not part of a database relationship Schema Example Imagine we have an extension called 'My Extension' and an entity called foobar. The name of the table is #__myextension_foobars. This schema describes the table: Field Datatype NOT NULL AUTO INC UNSIGNED DEFAULT id INTEGER X X X NULL content TEXT X       checked_out INTEGER X   X 0 checked_out_time DATETIME X     0000-00-00 00:00:00 params TEXT X       ordering INTEGER X   X 0 hits INTEGER X   X 0 published TINYINT(1) X   X 0 This table uses all of the common fields and uses an auto-incrementing primary keyID field. When we come to define our own tables we must ensure that we use thecorrect data types and NOT NULL, AUTO INC, UNSIGNED and DEFAULT values. The SQL displayed below will create the table described in the above schema: CREATE TABLE `#__myextension_foobars` ( `id` INTEGER UNSIGNED NOT NULL DEFAULT NULL AUTO_INCREMENT, `content` TEXT NOT NULL DEFAULT '', `checked_out` INTEGER UNSIGNED NOT NULL DEFAULT 0, `checked_out_time` DATETIME NOT NULL DEFAULT '0000-00-00 00:00:00', `params` TEXT NOT NULL DEFAULT '', `ordering` INTEGER UNSIGNED NOT NULL DEFAULT 0, `hits` INTEGER UNSIGNED NOT NULL DEFAULT 0, `published` INTEGER UNSIGNED NOT NULL DEFAULT 0, PRIMARY KEY(`id`)) CHARACTER SET `utf8` COLLATE `utf8_general_ci`; Date Fields We regularly use datetime fields to record the date and time at which an action has taken place. When we use these fields, it is important that we are aware of the effect of time zones. All dates and times should be recorded in UTC+0 (GMT / Z). When we come to display dates and times we can use the JDate class. The JDate class allows us to easily parse dates, output them in different formats, and apply UTC time-zone offsets. For more information about time zones, please refer to http://www.timeanddate.com. We often use parsers before we display data to make the data safe or to apply formatting to the data. We need to be careful how we store data that is going to be parsed. If the data is ever going to be edited, we must store the data in its RAW state. If the data is going to be edited extremely rarely and if the parsing is reversible, we may want to consider building a 'reverse-parser'. This way we can store the data in its parsed format, eradicating the need for parsing when we view the data and reducing the load on the server. Another option available tous is to store the data in both formats. This way we only have to parse data when we save it. Dealing with Multilingual Requirements Unlike ASCII and ANSII, Unicode is a multi-byte character set; it uses more than eight bits (one byte) per character. When we use UTF-8 encoding, character byte lengths vary. Unfortunately, MySQL versions prior to 4.1.2 assume that characters are always eight bits (one byte), which poses some problems. To combat the issue when installing extensions we have the ability to define different SQL files for servers, that do and do not support UTF-8. In MySQL servers that do not support UTF-8, when we create fields, which define a character length, we are actually defining the length in bytes. Therefore, if we try to store UTF-8 characters that are longer than one byte, we may exceed the size of the field. To combat this, we increase the length of fields to try to accommodate UTF-8strings. For example, a varchar(20) field becomes a varchar(60) field. We triple the size of fields because, although UTF-8 characters can be more than three bytes, the majority of common characters are a maximum of three bytes. This poses another issue, if we use a varchar(100) field, scaling it up for a MySQL server, which does not support UTF-8, we would have to define it as a varchar(300) field. We cannot do this because varchar fields have a maximum size of 255. The next step is slightly more drastic. We must redefine the field type so as it will accommodate at least three hundred bytes. Therefore, a varchar(100) field becomes a text field. As an example, the core #__content table includes a field named title. For MySQL severs that support UTF-8, the field is defined as: `title` varchar(255) NOT NULL default '' For MySQL severs that do not support UTF-8, the field is defined as: `title` text NOT NULL default '' We should also be aware that using a version of MySQL that does not support UTF-8 would affect the MySQL string handling functions. For example ordering by a string field may yield unexpected results. While we can overcome this using postprocessing in our scripts using the JString class, the recommended resolution is to upgrade to the latest version of MySQL.

Creating a Device Application File | New | Project will open the New Project window as shown. Expand the Visual Basic node and follow it up by expanding the Smart Device node as shown. There are three kinds of Smart Devices listed; Pocket PC 2003, Smartphone 2003 and Windows CE 5.0. For this article the Pocket PC 2003 is chosen. When you select Pocket PC 2003 in the left pane, the right hand pane shows many templates available for Pocket PC 2003. You will be able to create the application for CF 1.0 as well as CF 2.0. In this interface you may choose to create the following types of applications: Device Application: CF2.0 Forms APP for Pocket PC 2003 or later Device Application(1.0: CF1.0 Forms APP for Pocket PC 2003 or later Console Application: CF 2.0 non-graphic application Console Application(1.0: CF 1.0 non-graphic application Control Library : CF 2.0 controls for Pocket PC Class library can be used for creating dll's. Change the name of the default project name to something different. Here it is changed to Pocket2. When you click OK after changing the name of the project, the program creates a MyProject folder and a Form1.vb file which you see under Solution Explorer. You may rename the file. The interface functions very much like, as if you are creating a Windows Application. The difference is you will be displaying a small foot print device as shown in the next figure. Form1 is displayed in the design mode and a mainMenu1 item is added to the Control Tray. When you click on the mainMenu1 in the tray you get a visible cue as to what you should do next as shown. The mainMenu1 shows up with Smart Tasks as shown. Now click on the Edit Menu and this opens up the Type Here area where you can enter some text. Here "Test" has been entered. This will create a single menu item "Test". This is a nice interface where you can build up menu items very easily as shown in the next figure. All you need to do is just type in the area indicated by "Type Here". In addition to this you may also use other common controls from the toolbox. Placing Other Controls on the Form Because of the compact nature of the device with a reduced foot print, the controls available are a subset of the controls that you find normally in a desktop application. Where as controls in desktop can take a variety of arguments, the compact controls work with limited set of arguments. The next figure shows the device related controls that are available. Let us go ahead and drag and drop (or double click in the Toolbox), a DateTime Picker control and a textbox as shown in the next figure. Rearranging objects is a snap because Visual Studio 2005 has an excellent support for sizing and aligning objects. The grid lines automatically snap in place (notice the thin blue line tying the alignment of Textbox1 with the DataTimePicker control. The Form1 text was changed using the Form's property window to read "Testing a simple device". Attaching an Event to Test the Controls Let us make use of the click event of the TestTime sub menu item to read from the DataTimePicker control and display it in the Textbox. To begin with, let us make the Textbox's text to be empty. Using the code shown the next paragraph we can show the date we pick from the DataTimePicker to display in the textbox. You can get to the code page by clicking on the TestTime sub menu [MenuItem3] item in the design window. Note Form1.vb is renamed as MyFirstMobile.vb Books from Packt Software Testing with Visual Studio Team System 2008 Entity Framework Tutorial Microsoft AJAX Library Essentials: Client-side ASP.NET AJAX 1.0 Explained ASP.NET Data Presentation Controls Essentials Programming Windows Workflow Foundation: Practical WF Techniques and Examples using XAML and C# Visual SourceSafe 2005 Software Configuration Management in Practice LINQ Quickly BlackBerry Enterprise Server for Microsoft® Exchange   Testing the Device Click on the Build menu item to display the drop-down menu and choose to build the project. After the Build succeeds (you should see a build succeeded message at the bottom of the screen) click on Start Debugging (green arrow) by the side of the Debug menu item. This displays the Deploy Pocket2 window as shown. There are a number of Pocket PC devices shown with the highlighted as the default. Accept the default emulator and click on the Deploy button. When the deployment succeeds you should see a message to that effect in the Output window (you may access this from the View menu item). You will also see the emulator skin as shown in the next figure. Which changes into the following when the program gets loaded. Now click on the DateTimePicker control, pick a date as shown in the next figure. After picking the date click on the sub menu item of Test which is TestTime. This transfers the date information from the DateTimePicker and places it in the textbox after adding some text as shown. You may pick another date and test it again. When you try to close the device by hitting the close button at the top of the window the following window gets displayed. If you choose Yes, the device state gets saved and the next message gets displayed. Although a Pocket PC emulator was chosen you could get all the accessible devices using the Device Emulator sub menu item from the Tools menu as shown. When you click on the Device Emulation Manager... you will see all the available devices as shown. Get acquainted with the Object Browser The Object Browser is one place where you may find clues as to what is happening in your program, whether you are using the correct syntax, etc. Refer to this important resource as you develop your programs. Summary This article described a simple introductory application for mobile devices. The application deployment to a Pocket PC emulator was also described.

Zen Gift of Education Many distributions have special releases around Christmas and New Year. I was planning to look at some of these this month like last year's Ubuntu Christmas Edition. But instead I found a release that's useful enough to maintain all year around. ZenEdu is a Live distribution that packs a whole bunch of educational tools on top of the Slackware-based light-weight and zippy Zenwalk Linux. As per Zenwalk's Wiki, ZenEdu was initiated by a user on the distro's French forum last year in December. That time the distro contained mostly French-only educational programs. This year, several members of the Zenwalk Linux community decided to release an international edition of ZenEdu. The distro is a goldmine of open source educational software and also packs a detailed user manual, which shows the developers' serious approach to do things properly. The educational apps included in the distro cover a broad range of subjects. The ZenEdu ISO is about 700 MB and includes apps that'll help users with subjects like Astronomy, Mathematics, and Chemistry. Since learning is the core idea behind the distro, it goes beyond traditional curriculum subjects and also packs tools that'll teach students the basics of programming and music. Some of the tools I particularly like are Stellarium - the popular 3D planetarium, Stardict - a multi-language dictionary, ghemical - a comprehensive computational chemistry package, Little Wizard that introduces the basics of programming to young students, and Maxima, for the manipulation of symbolic and numerical expressions, including differentiation, integration, ordinary differential equations, systems of linear equations, etc. If you want to learn music, train your ears with Solfege, and use TuxGuitar to edit and play guitar tablatures. What sets ZenEdu apart from other educational distros is that it bundles other productivity tools as well. This includes general-purpose applications like the IceWeasel web browser, IceDove email client, Pidgin for instant messaging, Kompozer for authoring web pages, and OpenOffice.org for word processing. Furthermore, the distro packs several other apps, which according to the developers, were chosen based on their usefulness to students while keeping in mind the things that might interest them. This includes a simple program to manage personal tasks and todo lists, a drawing program, a comic book viewer, a video editor, and a program to create a wide array of 3D content. However, there are dozens of free software educational tools that aren't included in this CD due to size considerations. But that's no problem. Since ZenEdu is based on Zenwalk, it too can be expanded with drag-and-drop modules. To create a new customize ZenEdu Live CD, browse and download the modules of educational apps you want and use the remastering application, isomaster to add them to your customized ZenEdu Live CD! The highlight of this distro though is the iTALC tool for teachers. iTALC, which stands for Intelligent Teaching And Learning with Computers, is a powerful cross-platform didactical tool that lets teachers view and control other computers in their network. Using iTALC teachers can see what's going on in computer labs and take snapshots, remote-control computers to support and help students, run a demo on all students' computers in real-time, send text-messages to students, cycle power and rebooting computers remotely, etc. ZenEdu has a special 'teacher' account pre-configured to run iTALC. Once logged in from that user, you can start iTALC and navigate through its interface, first adding student computers, and then controlling or monitoring them. ZenEdu's wiki page advices that if you'll be using the program regularly, you should save the 'teacher' account's iTALC directory (/home/teacher/.italc/) inside zenlive/rootcopy of the Live CD via isomaster. This will load the iTALC configuration the next time you boot the remastered Live CD. If you'll be using iTALC regularly you'd be well off installing ZenEdu on to your hard disk. Unfortunately, ZenEdu isn't installable. It's only a Live CD, and at best can be installed onto a USB Flash stick for portability. Most of the specialized distros I've played with, tend to be too specialized. They do what they are supposed to, but nothing more. ZenEdu is different in that, in a single CD, the developers have managed to squeeze a good number of educational apps as well as everyday tools. I hope members of the Zenwalk community, actively develop and maintain ZenEdu.   Some more articles by Mayank Sharma: Meet the Distro guy Making a Complete yet Small Linux Distribution

This is the third article in the article mini-series on Python LDAP applications by Matt Butcher. The first part deals with the installation and configuration of Python-LDAP library, and the binding-unbinding operations, and changing of the LDAP password. The second article takes a look at some of LDAP operations. In this article we will see some more LDAP operations such as add operation, delete operation etc. Then we will take a look at LDAP URL Library. The ModRDN Operation Another simple write operation that can be done through the Python-LDAP API is the ModRDN operation. This operation is used to change the relative DN (RDN) of a record. We can change an RDN using the modrdn() or modrdn_s() method. These two methods take three parameters: The full DN The new RDN An optional flag indicating whether the attribute corresponding to the RDN should be deleted from the record For example, if we want to change the UID attribute for uid=manny,ou=users,dc=example,dc=com, we will need to use a ModRDN operation, since this attribute is used in the DN. Here's an example for changing the UID from manny to immanuel. >>> l.modrdn_s('uid=manny,ou=users,dc=example,dc=com',... 'uid=immanuel', False)(109, [])>>> l.compare_s('uid=immanuel,ou=users,dc=example,dc=com','uid',... 'immanuel')1>>> In this example, we first use modrdn_s() to change the DN of a record from uid=manny,ou=users,dc=example,dc=com to uid=immanuel,ou=users,dc=example,dc=com. The False flag at the end of the modrdn_s() method indicates that the old UID (uid=manny) should be left in the record. The LDIF for uid=immanuel's record now, after the ModRDN operation, looks something like this: dn: uid=immanuel,ou=Users,dc=example,dc=comcn: Manny KantgivenName: MannyobjectClass: personobjectClass: organizationalPersonobjectClass: inetOrgPersonou: Userssn: Kantuid: immanueluid: manny If we had set the last flag to True instead of False, the manny attribute value of uid would have been deleted. More sophisticated DN modifications can be made with the rename() and rename_s() methods. But your OpenLDAP server will need to be running the HDB backend for all of the renaming features to work. The Add Operation The LDAP add operation is used to add new (complete) records to the directory information tree. Here, we will look at adding records through the add() and add_s() methods of the LDAPObject class. Both of these methods take only two parameters: The string DN of the new record A list of attribute tuples While the first parameter is straightforward, we've looked at dozens of DNs already; the second attribute is a little trickier. The addition list looks something like this: add_record = [ ('objectclass', ['person','organizationalperson','inetorgperson']), ('uid', ['francis']), ('cn', ['Francis Bacon'] ), ('sn', ['Bacon'] ), ('userpassword', ['secret']), ('ou', ['users'])] If there is only one value in the attribute value list, the value can be just a string – it need not be a list. Example: ('ou', 'user') is an acceptable alternative to ('ou', ['user']). The list of attributes is made up of two-value tuples, where the first item of each tuple is the attribute name, and the second value is a list of attribute values. All of the values are expected to be strings. If you have values in a dictionary, where the attribute name is the key and the attribute values are stored in a list in the dictionary value, you can use the ldap.modlist module's addModList() function to create an attributes list in the form specified above. Once you have a list in the correct format, writing it to the directory is just a matter of executing the add() or add_s() method. >>> l.add_s('uid=francis,ou=users,dc=example,dc=com', add_record)(105, [])>>> This line performs an LDAP add operation, sending this new data to the server. The server ensures that the new record adheres to the appropriate schemas (e.g. the schemas for the person, organizationalPerson, and inetOrgPerson object classes), and then writes the entry to the directory. As might be expected, the add() method functions the same way that the add_s() method does, except that it returns an ID number. The result must be retrieved using the result() method. We can dump the new entry from the server (using the dump_record.py program developed earlier in the series) to verify that the record is as we expect it to be: $ ./dump_record.py 'uid=matt,ou=users,dc=example,dc=com' 'uid=francis, ou=users,dc=example,dc=com'Password for uid=matt,ou=users,dc=example,dc=com:dn: uid=francis,ou=users,dc=example,dc=comcn: Francis BaconobjectClass: personobjectClass: organizationalPersonobjectClass: inetOrgPersonou: userssn: Baconuid: francisuserPassword: secret We can tell by comparing this record with the add_record list above that the record is correct. The main error encountered when adding is violating the schema, either by adding attributes that are not supported, or by failing to add required attributes. When one of these conditions is met, an exception will be raised. For example, if no structural object class is specified in the attributes, an OTHER exception will be raised. If a record does not contain the attributes used in the UID, a NAMING_VIOLATION will be raised. If a record is missing an attribute required by a structural object class, an OBJECT_CLASS_VIOLATION will be raised, and so on. Of course, since all of these are subclasses of LDAPError, these numerous exceptions can all be caught in a try/except clause like this: >>> try:... l.add_s('uid=william,ou=users,dc=example,dc=com', attrs )... except ldap.LDAPError, e:... print e.message['info']... This will catch any of the LDAP exceptions, and display some of the error text, rather than showing the stack trace. Now we are ready to move on to the most complicated of writing operations: the LDAP modify operation. The Modify Operation Here we will look at the LDAP modify operation, which is used for modifying attributes – adding, replacing, or removing them from already-existing records. The OpenLDAP command line tool ldapmodify provides one way of performing this operation. In the Python-LDAP library, the modify() and modify_s() methods provide asynchronous and synchronous methods for performing modifications to the directory information tree. The signature of these methods is same as that of the add methods. There are two parameters: the DN and a list of modification tuples. The main difference is that the form of the tuples in this modification list is different than those in the add methods. A tuple in a modification list has three items: The modification type The attribute name A list of attribute values Modification type is one of three different constants defined in the ldap module: MOD_ADD: This is used to add an attribute value. If the attribute already exists (and the schema permits multiple values), the new value will be added, and the old value will remain. MOD_DELETE: The attribute value will be removed, if it exists. MOD_REPLACE: The given attribute values will replace all other values for that attribute name. In other words, all old values for the attribute will be deleted, and then this value will be added. For example, a simple list for adding a new givenName to an existing entry might look like this: mod_attrs = [( ldap.MOD_ADD, 'givenName', 'Francis' )] This list contains only one attribute to be modified. It will (if successful) add a new givenName attribute to the specified record. The modification can then be done with code like this: >>> mod_attrs = [( ldap.MOD_ADD, 'givenName', 'Francis' )]>>> l.modify_s('uid=francis,ou=users,dc=example,dc=com', mod_attrs)(103, [])>>> This will add the specified attribute value to the uid=francis record that we created above. As a result, dumping the LDIF record will show the newly added attribute: dn: uid=francis,ou=users,dc=example,dc=comcn: Francis BacongivenName: FrancisobjectClass: personobjectClass: organizationalPersonobjectClass: inetOrgPersonou: userssn: Baconuid: francisuserPassword: secret The highlighted line above shows the newly added attribute value. The modifyModList() function in the ldap.modlist module can help convert modification lists stored in dictionaries to the appropriate tuple-based format. What if Francis decided that he preferred to go by Frank? We could perform a slightly more sophisticated modification, changing his givenName to Frank, and adding a second CN value: >>> mod_attrs = [... ( ldap.MOD_REPLACE, 'givenName', 'Frank' ),... ( ldap.MOD_ADD, 'cn', 'Frank Bacon' )... ]>>> l.modify_s('uid=francis,ou=users,dc=example,dc=com', mod_attrs)(103, [])>>> Notice that our modification list now has two different modifications. First, it will replace givenName. Second, it will add a new cn attribute value. The result will be something like this: dn: uid=francis,ou=users,dc=example,dc=comcn: Francis Baconcn: Frank BacongivenName: FrankobjectClass: personobjectClass: organizationalPersonobjectClass: inetOrgPersonou: userssn: Baconuid: francisuserPassword: secret If we wanted to change the UID attribute, we would have to use the modrdn() or modrdn_s() method, since uid is used in the DN. If we try to change it with modify_s() or modify(), we will get a NAMING_VIOLATION exception. Finally, we can use the modify methods to remove attribute values: >>> mod_attrs = [ (ldap.MOD_DELETE, 'cn','Francis Bacon') ]>>> l.modify_s('uid=francis,ou=users,dc=example,dc=com', mod_attrs)(103, [])>>> This will remove only the attribute value Francis Bacon from the cn attribute. If no such value exists, a NO_SUCH_ATTRIBUTE exception will be raised. Otherwise, the value will be discarded. Note that some attributes are required by the record's object classes to be present in an entry. Attempting to delete the last value for such an attribute will result in an OBJECT_CLASS_EXCEPTION being raised. Removing All Attribute Values Sometimes it is necessary to remove all of the values for an attribute in a record, instead of just one specific value, as we did above. Let's look at an example. First, we add a few attribute values – two descriptions: >>> mod_attrs = [ ... (ldap.MOD_ADD, 'description', 'Author of New Organon'),... (ldap.MOD_ADD, 'description', 'British empiricist') ... ]>>> l.modify_s('uid=francis,ou=users,dc=example,dc=com', mod_attrs)(103, []) Now we have a record with two new descriptions. We can perform a very specific search to verify this. >>> l.search_s('uid=francis,ou=users,dc=example,dc=com', ... ldap.SCOPE_BASE, '(uid=francis)',['description'])[('uid=francis,ou=users,dc=example,dc=com', {'description': ['Author of New Organon', 'British empiricist']})] This search looks at just the uid=francis record, and shows just the description attributes. Now, how can we delete both of these attribute values without having to supply the exact attribute values for each? We can do this removal by creating a modification entry that uses None instead of a string for the final item in the attribute tuple: >>> mod_attrs = [( ldap.MOD_DELETE, 'description', None )]>>> l.modify_s('uid=francis,ou=users,dc=example,dc=com', mod_attrs)(103, [])>>> A simple search will verify that both description attribute values have been deleted: >>> l.search_s('uid=francis,ou=users,dc=example,dc=com', ... ldap.SCOPE_BASE, '(uid=francis)',['description'])[('uid=francis,ou=users,dc=example,dc=com', {})]>>> The server returned one entry – one with the DN for uid=francis – but since there were no description attribute values, the dictionary is empty.

Built-In Search Engine Verity comes in package with ColdFusion. One of the reasons why people pay for ColdFusion is the incredible power that comes with this tool. It should be noted that one of the most powerful standalone commercial search engines is this tool. Some of the biggest companies in the world have expanded internal services with the help of the Verity tool that we will learn about. We can see that in order to start, we must create collections. The building of search abilities is a three-step process. There is a standard ColdFusion tag to help us with each of these functions. Create collections Index the collections Search the collections These collections can contain information about web pages, binary documents, and can even work as a powerful way to search cached query result information. There are many document formats supported. In the real business world, the latest bleeding-edge solutions will still store a previous version. Archived and shared documents should be stored in appropriate formats and versions that can be searched. Creating a Collection The first thing is to make our collection. See the ColdFusion Administrator under Data & Services. Here, we will be able to add collections and edit existing collections. There is one default collection included in ColdFusion installations. This is the bookclub demonstration application data. We will be creating a collection of PDF documents for this lesson. We have placed a collection of ColdFusion, Flex, and some of the Fusion Authority Quarterly periodicals in a directory for indexing. Here is the information screen for adding the collection through the administrator. We choose to select the Enable Category Support option. Also, there are libraries available for multiple languages if that is appropriate in a collection. We now see that there is a new collection for our devdocs. There are four icons to work with this collection. They are, from right to left, index, optimize, purge, and remove actions. The Name link takes us to the index action. The collection gives us the number of actual documents present, and the size of the index file on the server. The screen will show the details of the index as to when it was last modified, and the language in which it is stored. It lists the categories, and also shows the actual path where the index is stored. Here is a code version of creating a collection that would achieve the same thing. This means that it is possible to create an entire administrative interface to manage collections. It is also possible to move from tags to objects, and wrap up all the functions in that style. <cfcollection action="create" collection="devdocs" path="c:ColdFusion8veritycollectionsdocuments" /> If we have categories in our collection, and we want to get a list of the categories, then the following code must be used: <cfcollection action="categoryList" collection="bookClub" name="myCats" /><cfdump var="#myCats#"> Indexing a Collection We can do this through the administration interface. But here, we will do it as shown in the the following screenshot. This is a limited directory that we have used as an example for searching. This is the result of the devdocs submitted above. This gave a result of 12 documents with a search collection of the size, 4,611 Kb. Now, we will look at how to do the same search using code and build the index outside the administrator interface. This will require the collection to be built before we try to index files into it. The creation of the collection can also be done inside the administration interface or in code. It should also be noted that ColdFusion includes a security called Sandbox Security. These three core tags for Verity searching among many others can be blocked if you find it better for your environment. Just consider what is actually getting indexed and what needs to be searched. Hopefully, documents will be secured correctly and it will not be an issue. When we are making an index, we have to make sure that we can either choose to use a recursive search or not. A recursive search means that all the subdirectories in a document or web page search will be included in our search. It should also be noted that the service will not work for indexing other websites. It is for indexing this server only. <cfindex name="myCats" action="refresh" collection="bookClub" recurse="true" type="path" extensions=".html .htm .cfm .cfml" key="c:inetpubwwwrootdocuments" urlpath="http://localhost/documents/" /> Your collection has been indexed. It is important to note that there is no output from this tag. So we need to put some text on the screen to make sure the person using the site can know that the task has been completed. If we want to index a single file rather than a whole directory path, we can do it with this code: <cfindex action="refresh" collection="bookClub" recurse="true" type="file" extensions=".pdf" key=" c:inetpubwwwrootdocumentsColdFusioncf8_devguide.pdf" urlpath="http://localhost/documents/ColdFusion" /> Your collection has been indexed.

How to Integrate with CMS? While attempting integration of one CMS with another, some simple principles should be remembered. For all integration attempts, you have to consider the following aspects: Master-slave relationship: While integrating one CMS with the other, one of the applications act as the master and the other as the slave. If you integrate application A to application B, then application B will be considered as master. Master applications maintain authentication and sessions for both applications. While integrating Zen Cart with some other CMS, first consider whether Zen Cart will be the master or the slave. If you are integrating Zen Cart with an existing website, Zen Cart is going to be the slave. On the other hand, when you are adding blogging functionality to the Zen Cart shop by integrating WordPress with Zen Cart, Zen Cart is going to be the master. User and Group Management: One purpose of integrating two CMSs is to have a common user and group management system. Zen Cart integration may be tight, where both Zen Cart and an other CMS will use the same database for user and group management. On the other hand, loose integration will allow periodic or event-based synchronization of user or group databases. Tight integration becomes easier when both CMSs use the same type of user database. If the user databases are very different from each other, then tight integration may not be possible and some sort of fallback solution such as synchronizing the databases may be used. Visual integration: Users see the integration only through the visual integration. In fact, visual integration should be such that users will be unaware of integration attempt. While integrating the two CMSs, the visual template of the master should preferably be used for both CMSs. However, using a master's template system is difficult and a central template system should be developed which can be used for both applications. Now, we will see how to integrate Zen Cart with other CMSs. You will notice that at least one of the above-mentioned aspects is present in such integrations. Joomla!/Mambo If you are using Joomla!/Mambo and want e-commerce functionality, you have a number of choices. Among these, the best one is using the VirtueMart component. The VirtueMart component for Joomla!/Mambo is quite similar to Zen Cart or osCommerce. Only a few features of Zen Cart or osCommerce are missing in VirtueMart. However, if you still want to integrate Zen Cart into the existing Joomla!/Mambo website, you have two options-and neither is easier than the other: Use Zen Cart as a wrapper or, develop a component based on Zen Cart. Using Zen Cart as a wrapper is in its true sense not an integration. It runs separately and Joomla! provides a menu link. Clicking on this link will show Zen Cart in a wrapper window. If you are experienced with Joomla! or Mambo, you can figure out how a menu item can be added to show the application in a wrapper. However, adding a wrapper may appear to be an integration if you modify the Zen Cart template accordingly. As the Zen Cart shop appears in the wrapper, it would be wise not to use headers and sidebars in the Zen Cart template. Links to the categories and other menus can be provided in the headers. A separate login mechanism should also be provided in the Zen Cart template. Developing a bridge for Zen Cart and Joomla! is a hot topic in the Zen Cart forum. Users of both Joomla! and Zen Cart agree that integration or bridging of these two will be of great value. However, due to the framework of these two systems, developing such a bridge has some complexities and takes some time. Recently, a discussion on this topic has led to the development of such a bridge by the open-source enthusiasts. Please watch the following thread:http://tinyurl.com/65ypyu. Another possibility is JFusion plug-in for Joomla! (available at www.jfusion.org) which is a framework for integrating several forums to Joomla!. The developer of JFusion has proposed developing such a plug-in for Zen Cart as well. It is hoped that JFusion will be able to integrate Zen Cart to Joomla! soon. Drupal Drupal is a powerful CMS and is widely used. There are a wide range of modules available for Drupal and it is used for different types of websites. There are a great number of Drupal users who want to integrate Drupal and Zen Cart-as both are considered useful in their category. Until recently, there was no easy way to integrate Drupal and Zen Cart. Very recently, Zen Cart Integration module has been released as a development version. For now, it works on Drupal 5.x and Zen Cart 1.3.7. Once this module is installed and configured, you can create Zen Cart categories and products from Drupal. As other nodes, these products and categories will be displayed as nodes in Drupal. When visitors click on these products they see product details as a Drupal node, but when the product is added to cart, it redirects to the Zen Cart shop. This module also provides a single sign-on facility. For integrating Zen Cart into Drupal, download the module from http://drupal.org/project/zencart. Before we proceed with the integration of Drupal and Zen Cart, assume that you have installed Drupal and Zen Cart on the same server. Let us suppose, Drupal is installed in e:wwwdrupal57 directory and Zen Cart 1.3.7 is in e:wwwzc directory, and these two uses separate database on the same MySQL server. Follow these steps: Download and unzip Zen Cart integration module: For integrating Zen Cart into Drupal, download the module from http://drupal.org/project/zencart. On your computer, unzip the zencart-5.x-1.x-dev.tar.gz package. You will get a folder named zencart, under which there are some files and a subfolder named zencart. Copy files for Zen Cart: Inside the zencart subfolder you will find the includes folder. Copy this subfolder, that is /zencart/includes, to your Zen Cart installation directory, that is e:wwwzc. This will overwrite the e:wwwzcincludes directory, but will not overwrite any files. Once you have copied all the files in this folder, you are finished with Zen Cart. Install Zen Cart installation module in Drupal: Copy the zencart directory with all the files inside it, except the zencart subfolder, to Drupal's installation directory, that is e:wwwdrupal57. As an administrator in Drupal, you can install this module from Drupal's Administer | Site Building | Modules section. In the module list you will see the Zen Cart Integration module group. You will find the following modules in this group: Zencart-This is the main module for integrating Zen Cart shopping cart to Drupal. This is required by other modules in this group. Zencart Catalog-This module allows creation of Drupal nodes for Zen Cart products and categories. Zencart Category Node Hierarchy-This module depends on the Node Hierarchy module and organizes Zen Cart products and categories. Download the Node Hirarchy module from http://drupal.org/project/nodehierarchy and install it before enabling this module. To enable these modules, select checkboxes in Enabled column and click Save configuration button at the bottom of the list. Configure Zencart Integration module in Drupal: After enabling the modules, you can configure those from Administer | Site Configuration | Zencart Integration screen. The Zen Cart Status section will provide you information about your Zen Cart installation. The module will search and find the Zen Cart installation and show its version, path to Drupal installation and other information. The Zen Cart Settings section will give you the opportunity to mention the Zen Cart installation directory path. Type it into the Path to Zencart field. The Zen Cart Page Redirects section allows you to configure page redirects from the Zen Cart page to Drupal node. Zen Cart Catalog section allows you to configure redirect from the Zen Cart catalog items to Drupal. While using this integration module, you create Zen Cart catalog and products from Drupal. If you want to create these categories and products from inside Zen Cart and synchronize those with Drupal, then check Update product info on cron. This will synchronize product information both on Drupal and Zen Cart by running cron command on linux/unix. Checking Redirect Product Info Pages will automatically redirect visitors from the Zen Cart product info pages to equivalent Drupal nodes. Similarly, checking Redirect Category Listing Pages will automatically redirect visitors from the Zen Cart category pages to equivalent Drupal nodes. The Zen Cart Users section allows you to configure single sign-on options for Drupal and Zen Cart. If you want to allow Zen Cart existing customers to login to Drupal, then check the Allow Zen Cart Customers to login to Drupal checkbox. On the other hand, if you want to allow Drupal users to login to Zen Cart as customers, check Allow Drupal Users Customers to login to Zen Cart as Customers. Checking Allow Single Sign-On will allow users to login once and access both Drupal and Zen Cart.                                                                                                                                                                                                                                                                                                         The Zencart Integration screen has the following sections: Once you have configured these options, click the Save configuration button, or revert to defaults by clicking the Reset to defaults button. Create Content Type in Drupal for Zen Cart categories and products: If you have ever used Drupal, you know how to create content types in Drupal. You can add new content type from Administer | Content Management | Content types | Add content type. Now you will get a Zen Cart Catalog group. From this section you can define whether this type will be used as a Zen Cart product or category. You can also configure node hierarchy-ability to be parent or child (default is parent). In the Identification section, type a human readable name, for example Zen Cart Product, in the Name field. Then type a machine readable name of this content type, for example zc_product, in the Type field. Provide a description of this content type in the Description field. In the Submission Form section, provide a label for the title and body field, minimum number of words, and explanation or submission guidelines. Configure default options in the Workflow section. Finally, click the Save content type button. Create two content types—one for the Zen Cart category and another for the Zen Cart product. Add Category and Product in Drupal: You can create categories and products from Create Content section. In the list, click on Zen Cart Category. This will open Submit Zen Cart Category form. In this form, type the category name in Title field, type a description of this category in Body field. In the Node Hierarchy section, you can select a parent category. Check Category is Active to make this category visible. Configure other options like Menu settings, URL path settings, Publishing options, and so on and click the Submit button to create the category Similarly, you can create Zen Cart products by clicking on the Zen Cart Product content type. This will display the Submit Zen Cart Product form. Fill in the Submit Zen Cart Product form with appropriate information, such as product name, model, quantity in stock, tax class, base price, and so on. You can select its parent category in the Node Hierarchy section. Check the Create Menu option to make a menu item for this product. Configure other options like Menu settings, URL path settings, Publishing options, and so on and click the Submit button to create the product. Test Zen Cart Integration to and from Drupal: Now it is time to test whether the Drupal-Zen Cart integration is working or not. First, go to your Zen Cart shop, for example, http://localhost/zc. There you will find the categories and products you have added. Click on any of these, and you will be redirected to the respective Drupal node. Again, in the Drupal, click on a product link, type a quantity and click the Add to Cart button. That will redirect you to the Zen Cart shop's Your Shopping Cart Contents page. Similarly you can test single sign-on features by signing in to either Drupal or Zen Cart and trying to purchase items from these two shops. Gallery2 Gallery2 is a web-based software product that lets you manage photos on your own website. It creates a catalog of photos which visitors can view as thumbnails as well as in its original size. It has an intuitive interface to create and maintain albums. It can create thumbnails automatically and can be used for image resizing, rotation, ordering, captioning, searching, and some other functions. You can use Gallery2 to build a community site for sharing photos. You can create the community using Gallery2 and registered users can share their photographs by uploading their own photos. You need to integrate Gallery2 with Zen Cart if you want to sell photos from your photo gallery. Gallery2 has a great mechanism to integrate with Zen Cart. The Gallery2/Zen Cart integration module is available at the Gallery2 download site http://dakanji.com/g2stuff/zcg2-3_2_1a-full.zip. Using it, users can organize their photos and other multimedia files into Gallery2, and offer them for sale through Zen Cart. In integrating Gallery2 with Zen Cart, you have to configure Zen Cart first. Follow these steps for Zen Cart: Download the Gallery2/Zen Cart Integration module and extract it. Copy the zencart/includes folder into your Zen Cart installation directory. This directory contains some templates for Zen Cart. Copying these files will not overwrite any existing file. Login to your Zen Cart administration panel and create a new product category, such as Photographs. Photo items from Gallery2 will go to this category. Select Tools | Template Selection and choose one of the Gallery2 Integration templates provided. You can take a copy of the template folder (../includes/templates/pgxxx) and modify stylesheet.css. You can also modify these templates. Edit ../includes/languages/pgxxx/english.php if you want to change language strings or date formats. Replace ../includes/templates/pgxxx/images/logo.gif with your site's logo. Remember that for Gallery2/Zen Cart integration, both Zen Cart and Gallery2 data tables need to be in one database. In Gallery2, you need to make the following changes: Upload the module files in the gallery2/ directory to your Gallery2 installation's modules directory. In Gallery2 Site Administration, click on Plugins and find Zen Cart under the Commerce heading. Then click Install. After Installation, click Configure. Enter the entire server path to your Zen Cart installation, for example, /home/your_name/public_html/zencart/. Select the category you created in Zen Cart earlier (for example Photographs) from the drop-down menu. Click activate next to the Zen Cart listing on the module page. Refresh the page and click on the Zen Cart link under Admin Options to edit product details. Edit permissions for the individual items as you wish. The module will have assigned permissions to non-album items on activation. If you do not want to sell an item, you will need to disable that item in Zen Cart as the module adds all data items in your gallery to Zen Cart. You can add photograph items from Gallery2. Adding any item to the Gallery2 album will simply show that item in Zen Cart. You can add product options from Gallery2 by clicking on the Zen Cart link in your Gallery2 site administration menu. When you have installed the Gallery2/Zen Cart bridge, you will find a product type in Zen cart named Product-Gallery. All the items from Gallery2 need to be of this type. If you edit any item from Zen Cart and change the product type of any Gallery2 item, the link with the Gallery2 will be broken. Also, note that the Gallery2 bridge will co-exist with Zen Cart image handler and lightbox add-on for Zen Cart. These will handle product images for Zen Cart, whereas Gallery2 add-on only handles images added in Gallery2. You cannot assign the Main category in Zen Cart as the root product category for Gallery2. The category you are selecting in the Gallery2 bridge configuration must be a sub-category product. Once the configurations are done, you can see the photographs from Zen Cart. Visitors can also order photographs from Zen Cart. While you are in Gallery2, you can also place an order by clicking the add to cart link, which is redirected to Zen Cart. WordPress WordPress is an extremely powerful and widely used open-source blogging platform. It has a wide community of developers and users, and almost all kinds of plugins are available for it. Although there are some shopping cart plugins for WordPress, they are not full-blown shopping carts like Zen Cart or osCommerce. E-commerce plug-ins available for WordPress have limited features. Those who are running blogs using WordPress may want to integrate it with Zen Cart to provide e-commerce functionality to their blogs. In fact, there is a Zen Cart module for integrating these two. You can download that module from www.zen-cart.com. After downloading the plug-in WordPress on Zen Cart, you have to install it on the webserver. You can install the plug-in in two ways: first, in an environment where you have a working WordPress installation, and second, when you have not installed WordPress. WordPress and Zen Cart Installed in Separate Directories When you have an existing installation of WordPress, generally it will be in a separate directory from that of the Zen Cart installation. If your web document root directory is public_html, then the installation directories may be: /public_html/blog and /public_html/shop. Follow these procedures to install WordPress on Zen Cart plug-in: Step1: Install WordPress If you have not installed WordPress yet, then download the WordPress files from www.wordpress.org and unzip the files. Then, upload the files to your webserver's /public_html/blog directory. Now, change the permission of this directory to 777 and point your browser to http://yourdomain.com/blog/wp-admin/setup-config.php. The installation wizard for WordPress will be displayed. Follow the instructions on the wizard and give the necessary information. Once all of the information is given, WordPress will be installed. Step 2: Configure WordPress During installation, an administrative account will be created. Note the username and password for this account. Then, point your browser to http://yourdomain.com/blog/wp-admin/. The login page will be displayed. Type the username and password for the administrative account and click on the Login button. You will see the dashboard for administering WordPress. Go to Options | General. Now, change the Blog Address (URL) to Zen Cart's URL http://yourdomain.com/shop/. From the administration dashboard, go to Presentation | Themes and select WordPress Default 1.6. Step 3: Upload WordPress on Zen Cart When you unzip the WordPress on Zen Cart plug-in zip file, you will find that there is a directory called ZC_ROOT and WP_ROOT. Now, upload the contents of ZC_ROOT directory to Zen Cart's installation path on the server, that is, /public_html/shop/. Similarly, upload the contents of the WP_ROOT directory to WordPress' installation path, that is, /public_html/blog. Before uploading the contents of the ZC_ROOT directory, please change the name of the /ZC_ROOT/includes/templates/MY_TEMP/ directory to that of the template directory you are using for your Zen Cart shop Step 4: Edit WordPress File For older versions of WordPress, you may need to edit the /wp-include/template-loader.php file. Open the file in a text editor and replace all exit; with return;. However, you may not need this for the newer versions of WordPress. WordPress 2.3.1 can work without this modification. First, try without this modification. Step 5: Edit Zen Cart File You also need to edit another file in the Zen Cart installation. Open the /includes/extra_configures/wordpress-config.php file under the Zen Cart installation folder and find the following line: define ('ABSPATH','/var/www/vhost/example.com/public_html/blog/'); Type the appropriate WordPress path, that is, /home/username/public_html/blog/. The above line will look like this: define ('ABSPATH','/home/suhreed/public_html/blog/'); If you are trying it on Windows, you may need to put the absolute path, as in, e:/www/blog. Step 6: Configure Sideboxes from Layout Boxes Controller Once the file modifications have been done, login to the Zen Cart administration panel. Go to Tools | Layout Boxes Controller. The screen will notify you that some new sideboxes-wp_cats.php, wp_archives.php, wp_pages.php, wp_links.php, and wp_sidebar.php-have been found. To use these sidebars, click on the reset button at the bottom. To show these sideboxes on your Zen Cart shop, click on the sidebar and change its left/right column status.

Fundamentals of XHTML MP Since XHTML MP is based on XHTML, certain syntactical rules must be followed. Making syntactical errors is a good way to learn a programming language, but so that you don't get frustrated with them, here are some rules you must follow with XHTML MP! Remember, HTML is very forgiving in terms of syntax, but make a small syntax error in XHTML MP and the browser may refuse to show your page! Overall, XHTML elements consist of a start tag—element name and its attributes, element content, and closing tag. The format is like: <element attribute="value">element content</element> XHTML Documents Must be Well Formed Since XHTML is based on XML, all XHTML documents must adhere to thebasic XML syntax and be well formed. The document must also have a DOCTYPE declaration. Tags Must be Closed! All open tags must be closed. Even if it is an empty tag like "<br>", it must be used in the self-closed form like "<br />". Note the extra space before the slash. It's not mandatory, but makes things work with some older browsers. If you can validate within your editor, make it a practice to do that. Also cultivate the habit of closing a tag that you start immediately—even before you put in the content. That will ensure you don't miss closing it later on! Elements Must be Properly Nested You cannot start a new paragraph until you complete the previous one. You must close tags to ensure correct nesting. Overlapping is not allowed. So the following is not valid in XHTML MP: <p><b>Pizzas are <i>good</b>.</i></p> It should be written as: <p><b>Pizzas are <i>good</i>.</b></p> Elements and Attributes Must be in Lowercase XHTML MP is case sensitive. And you must keep all the element tags and all their attributes in lowercase, although values and content can be in any case. Attribute Values Must be Enclosed within Quotes HTML allowed skipping the quotation marks around attribute values. This will not work with XHTML MP as all attribute values must be enclosed within quotes—either single or double. So this will not work: <div align=center>Let things be centered!</div> It must be written as: <div align="center">Let things be centered!</div> Attributes Cannot be Minimized Consider how you would do a drop down in HTML: <select> <option value="none">No toppings</option> <option value="cheese" selected>Extra Cheese</option> <option value="olive">Olive</option> <option value="capsicum">Capsicum</option> </select> The same drop down in XHTML is done as: <select> <option value="none">No toppings</option> <option value="cheese" selected="selected">Extra Cheese</option> <option value="olive">Olive</option> <option value="capsicum">Capsicum</option> </select> The "selected" attribute of the "option" element has only one possible value and, with HTML, you can minimize the attribute and specify only the attribute without its value. This is not allowed in XHTML, so you must specify the attribute as well as its value, enclosed in quotes. Another similar case is the "checked" attribute in check boxes. XHTML Entities Must be Handled Properly If you want to use an ampersand in your XHTML code, you must use it as &amp; and not just &. & is used as a starting character for HTML entities—e.g. &nbsp;, &quot;, &lt;, &gt; etc. Just using & to denote an ampersand confuses the XML parser and breaks it. Similarly, use proper HTML Entities instead of quotation marks, less than/greater than signs, and other such characters. You can refer to http://www.webstandards.org/learn/reference/charts/entities/ for more information on XHTML entities. Most Common HTML Elements are Supported The following table lists different modules in HTML and the elements within them that are supported in XHTML MP version 1.2. You can use this as a quick reference to check what's supported. Module Element Structure body, head, html, title Text abbr, acronym, address, blockquote, br, cite, code, dfn, div, em, h1, h2, h3, h4, h5, h6, kbd, p, pre, q, samp, span, strong, var Presentation b, big, hr, i, small Style Sheet style element and style attribute Hypertext a List dl, dt, dd, ol, ul, li Basic Forms form, input, label, select, option, textarea, fieldset, optgroup Basic Tables caption, table, td, th, tr Image img Object object, param Meta Information meta Link link Base base Legacy start attribute on ol, value attribute on li Most of these elements and their attributes work as in HTML. Table support in mobile browsers is flaky, so you should avoid tables or use them minimally. We will discuss specific issues of individual elements as we go further. XHTML MP Does Not Support Many WML Features If you have developed WAP applications, you would be interested in finding the differences between WML (Wireless Markup Language—the predecessor of XHTML MP) and XHTML MP; apart from the obvious syntactical differences. You need to understand this also while porting an existing WML-based application to XHTML MP. Most of WML is easily portable to XHTML MP, but some features require workarounds. Some features are not supported at all, so if you need them, you should use WML instead of XHTML MP. WML 1.x will be supported in any mobile device that conforms to XHTML MP standards. Here is a list of important WML features that are not available in XHTML MP: There is no metaphor of decks and cards. Everything is a page. This means you cannot pre-fetch content in different cards and show a card based on some action. With XHTML MP, you either have to make a new server request for getting new content, or use named anchors and link within the page. You could use the <do> tag in WML to program the left and right softkeys on the mobile device. Programming softkeys is not supported in XHTML MP; the alternative is to use accesskey attribute in the anchor tag (<a>) to specify a key shortcut for a link. WML also supports client-side scripting using WMLScript—a language similar to JavaScript. This is not supported in XHTML MP yet, but will come in near future in the form of ECMA Script Mobile Profile (ECMP). WML also supported client-side variables. This made it easier to process form data, validate them on the client side, and to reuse user-filled data across cards. This is not supported in XHTML MP. With XHTML MP, you have to submit a form with a submit button. WML allowed this on a link. WML also had a format attribute on the input tag—specifying the format in which input should be accepted. You need to use CSS to achieve this with XHTML MP. There are no timers in XHTML MP. This was a useful WML feature making it easier to activate certain things based on a timer. You can achieve a similar effect in XHTML MP using a meta refresh tag. The WML events ontimer, onenterbackward, onenterforward, and onpick are not available in XHTML MP. You can do a workaround for the ontimer event, but if you need others, you have to stick to using WML for development. XHTML MP also does not support the <u> tag, or align attribute on the <p> tag, and some other formatting options. All these effects can be achieved using CSS though. Summary In this article, we had a look at the fundamentals of XHTML MP and also at the grammar that must be followed for development with it. Next, we listed different modules in HTML and the elements within them that are supported in XHTML MP version 1.2. We finished the article by listing the important WML features that are not available in XHTML MP.

The report also states that blogs are profitable, it says: The majority of bloggers we surveyed currently have advertising on their blogs. Among those with advertising, the mean annual investment in their blog is $1,800, but it’s paying off. The mean annual revenue is $6,000 with $75K+ in revenue for those with 100,000 or more unique visitors per month. It is interesting to note that the majority of bloggers now display advertising. One of the most encouraging statistics is that the proportion of people blogging about their jobs and on behalf of their business is now so high: About half of bloggers are professional bloggers — blogging is not necessarily their full-time job, but they blog about their industry or profession in an unofficial capacity. 12% of bloggers blog in an official capacity for their company. The amount of cross-over between the groups is also interesting. It shows that personal and business blogging can be successfully combined: More than half of professional and corporate bloggers are also personal bloggers. This could be on a separate blog, or they may blog about personal interests within their professional blog. Corporate bloggers: 69% are also personal bloggers 65% are professional bloggers Professional bloggers: 59% are also personal bloggers 17% are corporate bloggers It’s very encouraging to see the positive benefits being enjoyed by business and professional bloggers, with the majority of those surveyed reporting a positive impact as a result of their blog. Half of them say they are better known in their industry and a quarter see their blog as a useful résumé enhancement. Impact of blogging on professional life: Business bloggers also report that blogging has brought many unique opportunities that wouldn’t have otherwise been available. Taking part in an event, contributing to a print publication or even appearing on radio or TV are the kinds of things they are involved in, thanks to their blog. Have you been invited to any of the following as the result of your blog? Blogging is a time consuming activity. This is confirmed by the report which shows that a quarter of bloggers spend over 10 hours per week on their blog and nearly half spend 5 hours or more. Time spent blogging each week: As I mention in WordPress For Business Bloggers, many bloggers take on help to run their blog. This is particularly true for corporate or business bloggers, of whom nearly 20% have paid staff working for them. Blogs with higher Technorati authority are updated more frequently than those with less authority, as the report states: The Technorati Top 100 are prolific, with 43% posting ten times per day or more often. Only 8% post once a day or less frequently, compared to 13% of the next 500 bloggers, and 22% of the next 5000 bloggers. I highlight the importance of using tags in WordPress For Business Bloggers, and this is borne out by the data. Technorati top 100 bloggers are twice as likely to tag their posts. Percentage of bloggers who use tags: Promoting a blog well is key to its success and the report shows us the top traffic-building strategies used. These are particularly important for business bloggers, so all the techniques highlighted in the chart below are covered in WordPress For Business Bloggers, you’ll find many of them in Chapter 7, Supercharged Promotion: The vast majority of bloggers are tracking their site visitors and monthly page views, with Google Analytics being used by two thirds of them. Using Google Analytics with WordPress is covered in detail in the book, WordPress For Business Bloggers. Direct revenue generation is becoming an important aspect of blogging, with the majority of bloggers now displaying ads, affiliate marketing or other form of revenue generation (this subject is covered in detail in Chapter 10 of WordPress For Business Bloggers): The report data seems to suggest that the medium of blogging is gaining credibility and being taken more seriously as a source of information. 37% of bloggers have been quoted in the traditional media as a result of one of their posts. This is encouraging for business bloggers who use their blog as a PR tool. All in all, the State of the Blogosphere 2008 report makes encouraging reading for business bloggers as well as anyone who is thinking about starting a blog for their business. A blog can be a tremendously powerful tool for any business and using a top quality platform like WordPress makes running a blog extremely easy.