Creating a Java wrapper for your report

This recipe teaches you how to design a simple wrapper class in Java that wraps JasperReports functionality to process and compile an existing JRXML file, fetch application data, and combine the processed JRXML with application data to generate and save your JasperReport in PDF format.

Getting ready

Refer to the installPostgreSQL.txt file included in the source code download for this chapter to install and run PostgreSQL, which should be up and running before you proceed.

The source code of this chapter also includes a file named copySampleDataIntoPGS.txt, which helps you create a database named jasperdb9 and copy sample data for this recipe into the database.

You will need Java Development Kit (JDK) version 1.6.X to compile and run the Java application of this recipe. You will find all the necessary downloads and instructions on Sun's official website. After installing JDK, you will also set the JAVA_HOME environment variable to point to the main folder of your JDK installation (..jdk1.6.X).

You will be using a JRXML file named MonthlyCustomerReport.jrxml and two Java files named ConnectionManager.java and JasperReportsWrapper.java in this recipe. You will find these three files in the Task1 folder of the source code download of this chapter. In addition, you will also find two .bat files named compile.bat and run.bat and two folders named com and lib in the same Task1 folder. Copy all five files along with the com and lib folders (with their contents) to the C:JasperReportsCookBookSamples folder on your PC.

In order to compile JasperReportsWrapper.java, you will need the following seven JAR files:

  • jasperreports-3.6.0.jar
  • commons-beanutils-1.8.0.jar
  • commons-collections-3.2.1.jar
  • commons-digester-1.7.jar
  • commons-logging-1.1.jar
  • groovy-all-1.5.5.jar
  • iText-2.1.0.jar

You will find all seven JAR files in the ..JaspersoftiReport-nb-3.Xireportmodulesext folder of your iReport installation.

Although your JasperReportsWrapper.java will compile with these seven JAR files, your complete application will not run without the JDBC JAR file that contains the driver for PostgreSQL. The name of the JAR file is postgresql-8.2-506.jdbc3.jar. You can download the PostgreSQL JDBC driver from http://jdbc.postgresql.org/download.html. You can also find this postgresql-8.2-506.jdbc3.jar file in the ..JaspersoftiReport-nb-3.Xide8modulesext folder of your iReport installation.

Once you have all the JAR files ready, you will put them in the C:JasperReportsCookBookSampleslib folder on your PC. The compile.bat and run.bat files assume that all JAR files are located in the C:JasperReportsCookBookSampleslib folder.

How to do it...

The following steps demonstrate how to incrementally design a wrapper Java class to process your JasperReport and generate its PDF.

  1. Browse to the C:JasperReportsCookBookSamples folder on your PC into which you copied files from the Task1 folder from the source code for this chapter.
  2. Double-click the compile.bat file, and a command prompt will appear. It will compile your JasperReportsWrapper.java file and show the compilation results. After successful compilation, dismiss the command prompt by clicking the Close button on its top-right corner. Now you will see that a JasperReportsWrapper.class file will appear in the C:JasperReportsCookBookSamplescom folder.
    How to do it...
  3. Now double-click the run.bat file to execute the compiled JasperReportsWrapper class. You will see that your Java application displays a Connection with database established successfully message on command prompt. Dismiss the command prompt by clicking the Close button.
    How to do it...
  4. Open the JasperReportsWrapper.java file from the C:JasperReportsCookBookSamples folder on your PC in a text editor. The file contains code for your JasperReportsWrapper class. You will find five methods named connect2DB(), compileJRXMLFile(), fillReport(), saveReportInPDF(), and main() in the JasperReportsWrapper class. The first method named connect2DB() is ready to be used in the recipe. The connect2DB() method connects to your PostgreSQL database and returns the connection in the form of a Connection object. You will incrementally build the rest of the four methods in this recipe to compile, fill, and save your JasperReport.
  5. Now you will use the JasperReports API to compile your MonthlyCustomerInvoices.jrxml file. For this purpose, type the following code in the try block of the compileJRXMLFile() method in the JasperReportsWrapper.java file.
    JasperReport jr = JasperCompileManager.compileReport(jasperXMLFileName);
if (jr != null)
System.out.println ("Your report compiled successfully");
return jr;

    After you have typed the code, the complete compileJRXMLFile() method will look as follows: 

    // Compile JasperReports XML file
public JasperReport compileJRXMLFile(String jasperXMLFileName)
{
try
{
   
JasperReport jr = JasperCompileManager.compileReport(jasperXMLFileName);
if (jr != null)
System.out.println ("Your report compiled successfully");
return jr;
   
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

    Save your JasperReportsWrapper class.

  6. Now add a call to the compileJRXMLFile() method at the end of the existing code in the main() method of your JasperReportsWrapper class. The call to the compileJRXMLFile()file will look as follows:
    JasperReport compiledJasperReport = wrapper.compileJRXMLFile(path2JRXMLFile);

    After adding the call, the main() method will become: 

    public static void main (String[] args)
{
   
JasperReportsWrapper wrapper = new JasperReportsWrapper();
     
Connection connection = wrapper.connect2DB( dbServerAdd, dbServerPort, dbName, dbUser, dbPass);
// Compile JRXML file
JasperReport compiledJasperReport = wrapper.compileJRXMLFile(path2JRXMLFile);
}

    Save your JasperReportsWrapper class.

  7. Double-click the compile.bat file to compile the JasperReportsWrapper class. A command prompt will appear. It will compile your application. After successful compilation, dismiss the command prompt by clicking on the Close button.
  8. Double-click the run.bat file to execute the compiled JasperReportsWrapper.class file. You will see that your Java application displays Connection with database established successfully and Your report compiled successfully messages. Dismiss the command prompt by clicking the Close button.
  9. Next you will fill your compiled JasperReport with your application data. You will use the Connection object that you saw earlier in step 4 to connect to your PostgreSQL database. Recall from step 4 that connect2DB() method returned this Connection object. You will pass the Connection object to the FillManager class of JasperReports by typing the following code in the try block of the fillReport() method of the JasperReportsWrapper class:
    if (connection != null)
{
JasperPrint jp =
JasperFillManager.fillReport(jr, params, con);
if (jp != null)
System.out.println (" Your report filled with application data");
return jp;
}

    After typing the code, the fillReport() method will look as follows: 

    // Fill data in compiled JasperReports file
public JasperPrint fillReport ( JasperReport jr, Map params, Connection con)
{
try
{
if (connection != null)
{
JasperPrint jp = JasperFillManager.fillReport(jr, params, con);
if (jp != null)
System.out.println (" Your report filled with application data");
return jp;
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}

    Save your JasperReportsWrapper class.

  10. Now add a call to the fillReport() method at the end of the existing code in the main() method of your JasperReportsWrapper class, as shown below:
    JasperPrint jasperPrint = wrapper.fillReport(compiledJasperReport, null, connection);

    After adding the call, the main() method will become: 

    public static void main(String[] args)
{
JasperReportsWrapper wrapper = new JasperReportsWrapper();
Connection connection = wrapper.connect2DB( dbServerAdd, dbServerPort, dbName, dbUser, dbPass);
// Compile JRXML file
JasperReport compiledJasperReport = wrapper.compileJRXMLFile(path2JRXMLFile);
// Fill data in compiled JRXML file
    
JasperPrint jasperPrint = wrapper.fillReport( compiledJasperReport, null, connection);
}

    Save your JasperReportsWrapper class.

  11. Double-click the compile.bat file to compile the JasperReportsWrapper class. A command prompt will appear that will compile your Java file. After successful compilation, dismiss the command prompt by pressing the Close button.
  12. Now double-click the run.bat file to execute the compiled JasperReportsWrapper.class file. You will see that your Java application displays Connection with database established successfully, Your report compiled successfully, and Your report filled with application data messages. Click the Close button to dismiss the command prompt.
  13. 13 Next you will add code to save your report in PDF format. For this purpose, you will fill the saveReportInPDF() method of the JasperReportsWrapper class with Java code in its try block as follows:
    JasperExportManager.exportReportToPdfFile( jasperPrint, pdfFileName);
System.out.println ("Your report successfully saved in PDF");

    After typing the code, the saveReportInPDF() method will look like as follows: 

    // Compile, fill and save report in JasperReport
public void saveReportInPDF (JasperPrint jasperPrint, String pdfFileName)
{
try
{
   
JasperExportManager.exportReportToPdfFile( jasperPrint, pdfFileName);
         
System.out.println (" Your report successfully saved in PDF");
} catch (Exception e) {
e.printStackTrace();
}
}

    Save your JasperReportsWrapper class.

  14. Now add a call to the saveReportInPDF() at the end of the existing code in the main() method of your JasperReportsWrapper class as follows:
    wrapper.saveReportInPDF(jasperPrint, pdfFileName);

    After adding the call, the main() method will become: 

    public static void main(String[] args)
{
JasperReportsWrapper wrapper = new JasperReportsWrapper();
Connection connection = wrapper.connect2DB( dbServerAdd, dbServerPort, dbName, dbUser, dbPass);
// Compile JRXML file
JasperReport compiledJasperReport= wrapper.compileJRXMLFile();
// Fill data in compiled jasper file
JasperPrint jasperPrint = wrapper.fillReport(
compiledJasperReport, null, connection);
// Save compiled and filled Jasper report in PDF
   
wrapper.saveReportInPDF(jasperPrint, pdfFileName);
      
}
  15. Double-click the compile.bat file to compile the JasperReportsWrapper class. A command prompt will appear that will compile your Java file. After successful compilation, click the Close button to dismiss the command prompt.
  16. Now double-click the run.bat file to execute the compiled JasperReportsWrapper.class file. You will see that your Java application displays Connection with database established successfully, Your report compiled successfully, Your report filled with application data, and Your report successfully saved in PDF messages. Click the Close button to dismiss the command prompt. Now you can browse to the C:JasperReportsCookBookSamples folder on your PC, where you will find a MonthlyCustomerInvoices.pdf file. This is the JasperReport, which your JasperReportsWrapper Java application has generated and saved for you.
    How to do it...

How it works...

Your Java application has compiled, generated, and saved your JasperReport in this recipe. In order to do all this, you used a wrapper class named JasperReportsWrapper, which wraps the functionality of JasperReports.

When you started, the JasperReportsWrapper class only had the functionality of connecting to a database. You incrementally built it to provide functionality to fetch application data, compile a JRXML file, supply application data to the compiled JRXML file, generate your JasperReport, and finally save it as a PDF file.

In step 5 of the recipe, you used a manager class of JasperReports named JasperCompileManager to compile your JRXML file. Then, in step 9, you used another manager class named JasperFillManager to fill the compiled report with application data. Note that the JasperFillManager class takes both a compiled JasperReport and a database Connection object. It internally fetches application data and provides the data to the compiled report to generate your actual JasperReport.

Finally, in step 13, you used another manager class named JasperExportManager to export your filled JasperReport into a PDF file, which you could browse and find in the C:JasperReportsCookBookSamples folder on your PC.

The following diagram shows the steps that are followed to generate a report:

How it works...

You can see four steps in the diagram; each step is represented by a box:

  1. Report Design: This step produces a JRXML file. You will normally design your report using iReport, as you have learned in the recipes of the first eight chapters of this cookbook.
  2. Compile Manager: The compile manager compiles the JRXML file into a JASPER file. You used the compile manager in step 5 of this recipe.
  3. Fill Manager: It takes a JASPER file and combines with actual report data to produce your report. You used Jasper's fill manager in step 9.
  4. Export Manager: Finally the last box named Export Manager takes your report and generates a PDF file for the report. This is what you did in step 13.
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