In this task you create a new report in BIRT Report Designer and name it ScriptedDataSrc.rptdesign.

In this task you create the new data source.

In this task, you create the new data set.

In the open( ) method, you open the data source. In the close( ) method, you do cleanup tasks. In this tutorial, there is no actual data source but typically you need to place some code in these methods. The open( ) method is the default selected method upon creating a data set.

When you create the data set, the open( ) method is selected by default. Use the open( ) method of the data set to do initialization, such as defining a counter and setting it to zero.

To create the output columns for a scripted data set, you must edit the data set. The columns you create in the data set editor are the columns that the data set fetch( ) method generates.

You place columns for a scripted data set in the same way as for a non-scripted data set.

Use the fetch( ) method to process row data. The fetch( ) method must return either true or false. Fetch( ) returns true to indicate that there is a row to process. Fetch( ) returns false to indicate that there are no more rows to process. The fetch( ) method also calculates the values of computed fields.

The report only has column headings at this point. To include data, you must add code to the fetch( ) method.

Use the data set open( ) method to perform initialization tasks. A typical initialization task is to get an instance of the Java object that provides the data for the report.

When referring to a Java object, first import its package into the JavaScript environment. For example, the following code imports the package com.yourCompany.yourApplication:

importPackage(Packages.com.yourCompany.yourApplication);

This statement is like the import statement in Java and allows you to omit the package name when referencing a class. This statement is normally the first line of code in the open( ) method. You typically follow the importPackage statement with code to create an instance of the Java object, as shown in the following example:

var myList = MyListFactory.getList();

A typical way of getting rows of data from a Java object is to use an iterator object. The open( ) method is the proper place to create an iterator object. For example, the following statement gets an iterator from myList:

var iterator = myList.getIterator();

Once you have a way to get rows of data from your Java object, use the fetch( ) method to call the Java method that returns the rows. The fetch( ) method determines if there are any more rows of data and returns false if there are none, as shown in the following code:

if(iterator.hasNext() == false ){
   return false;
}

At this point, the fetch( ) method can populate a row with data that it gets from the iterator, as shown in the following code:

var node = iterator.next( );
row[1] = node.getFirstCol( );
row[2] = node.getSecondCol( );
row[3] = node.getThirdCol( );

Then, you must return true to signal BIRT there is a valid row of data to process:

return true;

You can perform any cleanup in the close( ) method. This method is a good place to set to null any objects that you created. For example, the following code sets three object references to null:

myList = null;
iterator = null;
node = null;

If a scripted data source uses a custom Java class, that class must reside in a location where BIRT can find it. BIRT can find the Java class if its location meets any of the following requirements:

Before you deploy your BIRT report to an application server, you must place your Java class in a JAR file. You must then deploy that JAR file to the proper location on the application server so that the BIRT report viewer can find it at run time. For more information about where to deploy Java classes on an application server, see the chapter about deploying BIRT to an application server.