BIRT Connection Pooling Continued

Since writing a post on using a supplied connection with BIRT, many changes have occurred in the BIRT Project. Specifically connection pooling has been addressed with a JNDI property. This property can be set when using a JDBC data source.




To see how this can be used with Tomcat, see the
BIRT Wiki

If this does not meet your needs, the Data Tools project now supplies an extension point that can be used to alter the behavior of the standard BIRT JDBC driver. This extension point named org.eclipse.datatools.connectivity.oda.consumer.driverBridge can be implemented to intercept calls made to the JDBC driver and override the standard ODA calls like getConnection. If a user did not wish to use JNDI for connection pooling, but wanted to supply a connection through another means, this could be implemented using this extension point.

The driverTye and bridgeId attributes must be supplied for the extension point. The driverType specifies the ODA driver to which the bridge is applied. For the JDBC driver this should be set to org.eclipse.birt.report.data.oda.jdbc.OdaJdbcDriver.
The bridgeId specifies the element id of the extension that implements the ODA runtime. When using this to change the behavior of the JDBC driver this should be an extension that extends the JDBC runtime.

If you are using the Report Engine API to run reports, a connection object can be passed to engine using the application context as follows:

//Report Engine API snippet
HashMap contextMap = new HashMap();
contextMap.put( EngineConstants.APPCONTEXT_HTML_RENDER_CONTEXT, renderContext );
  
//add the connection object to the map
contextMap.put( "org.eclipse.birt.report.data.oda.subjdbc.SubOdaJdbcDriver", myconnectionobject );
  
task.setAppContext( contextMap );

A plug-in could then be created that implements the driverBridge extension point
to retrieve and use this connection. This plug-in would implement two extension points. The first should be the driverBridge and have values similar to the following:

   <extension
         id="org.eclipse.birt.report.data.testjdbc"
         point="org.eclipse.datatools.connectivity.oda.consumer.driverBridge">
         
   <bridge
   driverType="org.eclipse.birt.report.data.oda.jdbc.OdaJdbcDriver"
   bridgeId="org.eclipse.birt.report.data.testjdbc">
  </bridge>
   </extension>

The driverType specifies that the bridge will be applied to the BIRT JDBC driver.
The bridgeId specifies an element id of testjdbc, which can be defined in the same plug-in.

  <extension 
         point="org.eclipse.datatools.connectivity.oda.dataSource"> 
      <dataSource 
            odaVersion="3.0" 
            driverClass="org.eclipse.birt.report.data.testjdbc.MyJdbcDriver" 
            defaultDisplayName="Sample Driver Bridge" 
            setThreadContextClassLoader="false" 
            id="org.eclipse.birt.report.data.testjdbc"/>
   </extension>

This extension must implement the org.eclipse.datatools.connectivity.oda.dataSource
extension point. This is the runtime portion of an ODA driver. Because this bridge is being applied to the BIRT JDBC driver we can just extend the OdaJdbcDriver and change the behavior of the setAppContext and getConnection methods. The code below illustrates retrieving the connection from the application context. If the connection object does not exist in the application context, the default JDBC driver is used to retrieve the connection. This will allow the plug-in to be used within the designer using the credentials supplied in the Data Source editor and when deployed to an application that supplies the connection through the application context.

package org.eclipse.birt.report.data.testjdbc;
import java.sql.Connection;
import java.util.HashMap;
import java.util.Properties;

import org.eclipse.birt.report.data.oda.jdbc.*;
import org.eclipse.datatools.connectivity.oda.IConnection;
import org.eclipse.datatools.connectivity.oda.OdaException;

public class MyJdbcDriver extends OdaJdbcDriver {

 private Connection passedInConnection;


 public void setAppContext( Object context ) throws OdaException
 {
  HashMap ctx = (HashMap)context;
  passedInConnection = (java.sql.Connection)ctx.get("org.eclipse.birt.report.data.oda.subjdbc.SubOdaJdbcDriver");

 } 

 public IConnection getConnection(String connectionClassName) throws OdaException
 {
  if( passedInConnection != null){
   return new appContextDBConnection();
  }else{
   return new org.eclipse.birt.report.data.oda.jdbc.Connection();
  }
 }



 private class appContextDBConnection extends org.eclipse.birt.report.data.oda.jdbc.Connection
 {


  public void open(Properties connProperties) throws OdaException
  {
   super.jdbcConn = passedInConnection;   

  }

  public void close( ) throws OdaException
  {
   if ( jdbcConn == null )
   {
    return;
   }
   //should have call to return connection to the pool
   jdbcConn.close();
   jdbcConn = null;      
  }    



 }
}

The source for this plug-in is available here.