JasperReports is an open-source Java class library designed to aid developers with the task of adding reporting capabilities to Java applications. Since it is not a standalone tool, it cannot be installed on its own. Instead, it is embedded into Java applications by including its library in the application's CLASSPATH. JasperReports is a Java class library, and is not meant for end users, but rather is targeted towards Java developers who need to add reporting capabilities to their applications.

Although JasperReports is primarily used to add reporting capabilities to web-based applications via the Servlet API, it has absolutely no dependencies on the Servlet API or any other Java EE library. It is, therefore, by no means limited to web applications. There is nothing stopping us from creating standalone desktop or command-line Java applications to generate reports with JasperReports. After all, JasperReports is nothing but a Java class library providing an API to facilitate the ability to generate reports from any kind of Java application.

JasperReports requires a Java Development Kit (JDK) 1.3 or newer in order to successfully compile applications incorporating the JasperReports Java class library, and a Java Runtime Environment 1.3 or newer to successfully execute these applications. Older versions of JasperReports required a JDK to successfully execute JasperReports applications (strictly speaking, JasperReports required tools.jar to be in the CLASSPATH, and tools.jar is included in the JDK, not the JRE). However, from version 0.6.4, JasperReports is bundled with the Eclipse Java Development Tools (JDT) compiler, and no longer needs a JDK to execute deployed applications. Examples in this book are developed using JDK 1.5, but should compile and execute successfully with any JDK or JRE supported by JasperReports.

JasperReports is licensed under the Lesser GNU Public License (LGPL). This license was chosen for JasperReports since, unlike the GPL, it allows JasperReports to be used in both open-source and closed-source applications. Applications linking to the JasperReports Java class library do not need to be open-source. However, if you consider making modifications to the existing JasperReports source code, then your modifications will have to be released under the LGPL. See http://jasperreports.sourceforge.net/license.html for the complete license.

In addition to textual data, JasperReports is capable of generating professional reports including images, charts, and graphs. Some of the major JasperReports features include:

Each of these features is briefly described in the next few sections.

Exporting Capabilities

Reports generated with JasperReports can be exported to a number of formats, including PDF (Portable Document Format), XLS (Excel), RTF (Rich Text Format, a format readable and editable by most word processors, including, but certainly not limited to, Microsoft Word, OpenOffice.org Writer, StarOffice Writer, and WordPerfect), HTML (HyperText Markup Language), XML (Extensible Markup Language), CSV (Comma-separated Values), and plain text. Exporting reports to these formats is discussed in detail in Chapter 9. There is also a third-party library to export JasperReports' reports to the OpenDocument Format (ODF). The OpenDocument Format is a standard XML-based file format specification for office applications developed by the Organization for the Advancement of Structured Information Standards (OASIS). OpenOffice.org version 2.0 uses ODF as its default format.

Note

The JasperReports OpenDocument Format exporter was developed in the summer of 2005, as a part of Google's Summer of Code program. More information about the JasperReports OpenDocument Format exporter can be found at http://netmoc.cpe.ucf.edu/Projects/jasper.html.

The screenshot overleaf demonstrates some of the features of JasperReports, including data grouping, adding images and watermarks to a report, and exporting to a PDF:

When creating the report given in the screenshot, we took advantage of the data-grouping capabilities of JasperReports to group data by country, state, and city. This grouping allowed us to display the data in a logical, easy-to-follow way. We also took advantage of JasperReports' ability to display images and added a watermark and a logo in the report heading. The report font was modified in the header section to display it in a bigger font and in bold. Text was laid out in an easy-to-follow format.

In the screenshot, the freely available Evince document viewer was used to display the PDF report. Of course, reports exported to PDF can be viewed with any PDF viewer, including Adobe Acrobat, Foxit, and xPDF.

JasperReports leverages other open-source Java libraries to implement some of their functionality. Some of the libraries JasperReports builds on include:

The flow chart overleaf illustrates the typical workflow while creating reports with JasperReports:

When working with JasperReports, the first step is to create a report template as an XML file. XML report templates can be hand-coded or generated by a graphical report designer. Even though JasperReports' report templates are XML files, template filenames are given an extension of .jrxml. JasperReports XML templates are commonly referred to as JRXML files, which is the term we will use for them in this book.

Here is what a typical JRXML file looks like. We will discuss JRXML files in detail in Chapter 4.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jasperReport PUBLIC "//JasperReports//DTD Report Design//EN" "http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">
<jasperReport name="simple_template">
<title>
<band height="50">
</band>
</title>
<pageHeader>
<band height="50">
</band>
</pageHeader>
<columnHeader>
<band height="30">
</band>
</columnHeader>
<detail>
<band height="100">
</band>
</detail>
<columnFooter>
<band height="30">
</band>
</columnFooter>
<pageFooter>
<band height="50">
</band>
</pageFooter>
<lastPageFooter>
<band height="50">
</band>
</lastPageFooter>
<summary>
<band height="50">
</band>
</summary>
</jasperReport>

The JRXML file here mostly illustrates the main elements of a JRXML file. All elements in the file are optional except for the root<jasperReport> element. The above JRXML file, when compiled and filled, will generate an empty report; not very useful in its own right, but it can be used as a template for creating more useful reports. As can be seen in the above example, each main element of the JRXML file contains a<band> element as its only child element. Bands contain the data that is displayed in the report. In the above example, all bands are empty. In real JRXML files, bands contain child elements that are used to position, format, and display the actual report data, both textual and graphical. There are commercial and open-source visual design tools that can aid in the development of JRXML files. iReport, the official JasperReports graphical report designer, is covered in detail in Chapter 10.

JRXML files are compiled into a JasperReports native binary template, either programmatically by calling the appropriate methods on the JasperReports class library (compileReportToFile()), or by using a custom ANT task (used to compile multiple XML report design files in a single operation, by specifying the root directory that contains those files or by selecting them using file patterns) provided by JasperReports. The resulting compiled template is commonly known as the Jasper file, and is typically saved to disk with a .jasper extension. The Jasper file is then used to generate the final report, by providing it with its required data. This process is known as filling the report. A JRXML file has to be compiled only once. The generated Jasper file can be filled as many times as necessary to create and display reports.

Filled reports can be saved to disk in a JasperReports native format. Reports saved in this format are known as JasperPrint files. JasperPrint file names have a .jrprint extension. JasperPrint files can only be viewed with a JasperReports-specific viewer. JasperPrint files can be exported to other formats so that they can be opened with commonly available tools like PDF viewers and word processors. Exporting to other formats is discussed in detail in Chapter 9.

JasperReports has official online forums and a mailing list where questions can be asked. Both the forums and the mailing list archives can be found at the JasperReports site at http://sourceforge.net/projects/jasperreports.

The JasperReports website contains tips, tricks, JavaDoc API documentation, and a quick reference for JRXML elements. We won't repeat this information in this book, since it is readily available online. The JasperReports website can be found at http://jasperreports.sourceforge.net.

Commercial support and training is offered by JasperSoft and other third-party companies.

In this chapter we were introduced to JasperReports. We discussed the evolution of JasperReports from a small one-man project to a project backed and funded by a company that has raised millions of dollars in venture capital. We also had an overview of JasperReports, where we discussed that JasperReports is not a standalone reporting solution. Instead, it is a Java library that allows us to add reporting capabilities to our applications.

Next on the line was the JasperReports' open-source license (LGPL). The chapter provided us with a brief explanation of the features of JasperReports, including flexibility in report layout, the ability to display report data textually or graphically, and the ability to group report data. The JasperReports' class library dependencies were also discussed along with the typical workflow followed when designing reports. The chapter also provided us with the official online forums and mailing lists from where we can seek help.