Answer

Java has the java.util.Timer and java.util.TimerTask classes for scheduling tasks. These classes can be used within a Servlet and used to automate tasks in DB2 Alphablox such as clearing the DB2 Alphablox MSAS connection pool or rebuilding Essbase outline caches for which code examples are provided in this technical note.

A timer servlet such as this will run under any version of Alphablox but the connection pool code is specific to DB2 Alphablox 8.2 and later. The Essbase outline cache rebuild code is specific to DB2 Alphablox 8.4 and certain hotfix builds (8.2.1 build and later and 8.3 build 164 and later but not 8.2.1 FixPack 1)

Attached are the Java source file and 2 classes. The package for the attached classes is com.alphablox.support.samples. To use this sample, follow steps 1 through 4 below.

Installing the servlet

The exact steps vary depending upon your web application server but is essentially the same for all web application servers and for all servlets

1. Place the classes in the classes directory under the app

...\webapps\<yourapp>\WEB-INF\classes\com\alphablox\support\samples\

i.e.

C:\alphablox82\webapps\cases\WEB-INF\classes\com\alphablox\support\samples\

2. Update the web.xml to set the servlet params
The init params are actually optional as the code is defaulted to run at 1:00 am every nite). Your web.xml will be in:

...\webapps\<yourapp>\WEBWEB-INF\

i.e.

C:\alphablox82\webapps\cases\WEB-INF\


Add a new <servlet> section to the web.xml file like the following:

   <servlet>

      <servlet-name>TimerServlet</servlet-name>

      <servlet-class>com.alphablox.support.samples.TimerServlet</servlet-class>

      <load-on-startup>1</load-on-startup>

	  <init-param>

	    <param-name>initialTime</param-name>

		<param-value>4:00:00 AM</param-value>

		<description>The time of day to start the process</description>

	  </init-param>

	  <init-param>

	    <param-name>delay</param-name>

		<param-value>86400000</param-value>

		<description>Delay in milliseconds between requests:

24 hours (24*1000*60*60)</description>

	  </init-param>

    </servlet>

3. Load the new classes under the web application server
Navigate to the Alphablox admin pages to the applications tab, choose to edit your application, and then simply scroll to the bottom of the page and click "Save". This causes the application to be reloaded and starts the timer servlet.

4. Verify that the timer servlet is working
Verify that the timer servlet is working by checking your Alphablox Telnet console or server logs and you will see text like....

3/14/06 6:22:53 PM [INFO] [MSASConnectionPoolFlushTask]: run()
3/14/06 6:22:53 PM [INFO] [MSASConnectionPoolFlushTask]: pool cleared:   poolSize = 0:  openConnections = 0
3/14/06 6:22:53 PM [INFO] [EssbaseOutlineCacheRebuildTask]: run()
3/14/06 6:22:53 PM [INFO] [EssbaseOutlineCacheRebuildTask]: [EssbaseOutlineCacheRebuildTask] dataSourceName[0]=tbc rebuilding outlin
e Cache
3/14/06 6:22:53 PM [INFO] [EssbaseOutlineCacheRebuildTask]: [EssbaseOutlineCacheRebuildTask] dataSourceName[0]=tbc rebuilding outlin
e Cache
3/14/06 6:22:53 PM [INFO] [EssbaseOutlineCacheRebuildTask] dataSourceName[1]=sample4basic not found: Cannot find datasource: 'sample
4basic'

com.alphablox.blox.ServerBloxNotFoundException: Cannot find datasource: 'sample4basic'
        at com.alphablox.blox.AdminBlox.getDataSource(Unknown Source)
        at com.alphablox.support.samples.TimerServlet$EssbaseOutlineCacheRebuildTask.run(TimerServlet.java:181)
        at java.util.TimerThread.mainLoop(Timer.java:432)
        at java.util.TimerThread.run(Timer.java:382)
3/14/06 6:22:53 PM [INFO] [EssbaseOutlineCacheRebuildTask]: datasource db2 is of type IBM DB2 JDBC Type 4 Driver


Note: the EssbaseOutlineCacheRebuildTask contains negative tests as exhibited above

The code example

package com.alphablox.support.samples;

/**
 *
 * Simple timer servlet exmaple that clears the DB2 Alphablox MSAS connection pool
 * To use, add compiled class to you application classpath and add a servlet
 * section to your web.xml like:
 *  
 * <servlet>
 *    <servlet-name>TimerServlet</servlet-name>
 *       <servlet-class>com.alphablox.support.samples.TimerServlet</servlet-class>
 *       <load-on-startup>1</load-on-startup>
 *  <init-param>
 *    <param-name>initialTime</param-name>
 * <param-value>1:0:00 AM</param-value>
 * <description>The time of day to start the process</description>
 *  </init-param>
 *  <init-param>
 *    <param-name>delay</param-name>
 * <param-value>86400000</param-value>
 * <description>Delay in milliseconds between requests: 24 hours (24*1000*60*60)</description>
 *  </init-param>
 * </servlet>
 *
 * EssbaseOutlineCacheRebuildTask requires DB2 Alphablox versions:
 *  8.2.1 build 58 or later
 * 8.2.1 fp1 not supported
 *  8.3 build 164 or later
 *  8.4 or later
 *
 */

import com.alphablox.blox.repository.Log;
import com.alphablox.server.data.odbo.*;
import com.alphablox.blox.AdminBlox;
import com.alphablox.blox.ServerBloxNotFoundException;
import com.alphablox.blox.repository.DataSource;
import javax.servlet.http.HttpServlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Date;
import java.util.Calendar;
import java.text.DateFormat;
import java.text.ParseException;

public class TimerServlet extends HttpServlet
{
private final static long HOURS_24 = 1000 * 60 * 60 * 24; // in msecs

    private Timer         timer;
    private ServletConfig config;
    private String        startTime;
    private long          delay;
    private DateFormat    format = DateFormat.getTimeInstance();
    private Date          initialTime;    
   

    public void init( ServletConfig servletConfig ) throws ServletException
{
        super.init(servletConfig);
        this.config = servletConfig;


        try
{
        //  specify in the format as in 12.13.52 or 3:30pm
            initialTime = format.parse( config.getInitParameter( "initialTime") );
        }
        catch( ParseException pe )
{
        Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[TimerServlet]", "startTime could not be parsed from web.xml file" );
            initialTime = new Date();
        }

        try
{
            delay = Long.parseLong(config.getInitParameter("delay"));
        }
        catch( Exception e )
{
        Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[TimerServlet]", "delay Parameter could not be parsed from web.xml file" );
            delay = HOURS_24;
        }

        timer = new Timer();
        Calendar time = Calendar.getInstance();
        Calendar timeOfDay = Calendar.getInstance();

        try
{
            timeOfDay.setTime(initialTime);

            time.set(Calendar.HOUR_OF_DAY, timeOfDay.get(Calendar.HOUR_OF_DAY));
            time.set(Calendar.MINUTE, timeOfDay.get(Calendar.MINUTE));
            time.set(Calendar.SECOND, timeOfDay.get(Calendar.SECOND));

            Calendar startTime = Calendar.getInstance();
            startTime.add( Calendar.MINUTE, 1 );
           
            // make sure the first timer doesn't fire before the server starts
            if( time.before(startTime) )
            time = startTime;

            Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[TimerServlet]", "TimerServlet: Timer has been set for " + time.getTime() + " (" + delay + ")" );
           
            TimerTask msasTask    = new MSASConnectionPoolFlushTask();
            TimerTask essbaseTask = new EssbaseOutlineCacheRebuildTask();
            timer.schedule( msasTask, time.getTime(), delay );
            timer.schedule( essbaseTask, time.getTime(), delay );
        }
        catch( Exception e )
{
        Log.sendException( Log.MESSAGE_LEVEL_INFO , "[TimerServlet]", e );
        }
       
    }

    public void destroy()
    {
        timer.cancel();
        super.destroy();
    }
   
    public class MSASConnectionPoolFlushTask extends TimerTask
{
     /**
     * Flush the Alphablox MSAS connection pool. Implements TimerTask's required abstract run method.
     */
     public void run()
     {
       Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[MSASConnectionPoolFlushTask]", "run()" );
       try
{
        ODBOBridgeJavaAPI.clearPool();
        // If you are not using MSAS with Alphalbox, comment out the following line
        String logMessage =
        "pool cleared:   " +
"poolSize = " + ODBOBridgeJavaAPI.poolSize() + ":  " +
"openConnections = " + ODBOBridgeJavaAPI.getNumberOfOpenConnections();

           Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[MSASConnectionPoolFlushTask]", logMessage );
}
       catch( Exception e )
{
        Log.sendException( Log.MESSAGE_LEVEL_INFO , "[MSASConnectionPoolFlushTask]", e );
}
     }
     
} // end class MSASConnectionPoolFlushTask
   
    public class EssbaseOutlineCacheRebuildTask extends TimerTask
{
     /**
     * Rebuild the Alphablox EssbaseOutline Caches. Implements TimerTask's required abstract run method.
     */
   
    private AdminBlox     adminBlox       = new AdminBlox();
    private String[]      dataSourceNames = { "tbc", "sample4basic", "db2" };
    private DataSource[]  dataSources     = new DataSource[dataSourceNames.length];
   
 
     public void run()
     {
      String logMessage      = "";
     
       Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[EssbaseOutlineCacheRebuildTask]", "run()" );
       
    // note: you can do adminBlox.getDataSources() to get all the DataSources
    // instead of picking specific ones as done here
    //
    for( int i=0; i< dataSourceNames.length; i++ )
    {
    try
{
    dataSources[i] = adminBlox.getDataSource( dataSourceNames[i] );
   
    if( dataSources[i].getAdapterName().equals(DataSource.ADAPTER_ESSBASE) || dataSources[i].getAdapterName().equals(DataSource.ADAPTER_ESSBASEENTERPRISE) )
{
    // there are 3 forms of updateOutlineCache:
    //  .updateOutlineCache();
    //  .updateOutlineCache(String userName, String password);
    //  .updateOutlineCache(Object credential)
    //
    logMessage = "[EssbaseOutlineCacheRebuildTask] dataSourceName[" + i + "]=" + dataSourceNames[i] + " rebuilding outline Cache";
    Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[EssbaseOutlineCacheRebuildTask]", logMessage );  
   
    dataSources[i].updateOutlineCache();
           
    logMessage = "[EssbaseOutlineCacheRebuildTask] dataSourceName[" + i + "]=" + dataSourceNames[i] + " rebuilding outline Cache";
    Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[EssbaseOutlineCacheRebuildTask]", logMessage );  
}
    else
    {
    logMessage =  "datasource " + dataSourceNames[i] + " is of type " + dataSources[i].getAdapterName();
    Log.sendMessage( Log.MESSAGE_LEVEL_INFO , "[EssbaseOutlineCacheRebuildTask]", logMessage );  
    }
}
    catch( ServerBloxNotFoundException sbnfe )
{
    String messageString = "[EssbaseOutlineCacheRebuildTask] dataSourceName[" + i + "]=" + dataSourceNames[i] + " not found";
    Log.sendException( Log.MESSAGE_LEVEL_INFO , messageString, sbnfe );
}
    catch( Exception e )
{
    String messageString = "[EssbaseOutlineCacheRebuildTask] dataSourceName[" + i + "]=" + dataSourceNames[i];
    Log.sendException( Log.MESSAGE_LEVEL_INFO , messageString, e );
}
    }
   
     } // end run()
     
} // end class EssbaseOutlineCacheRebuildTask
   
} // end class TimerServlet