org.opensubsystems.patterns.backgroundtask.www
Class BackgroundTaskListener

java.lang.Object
  org.opensubsystems.patterns.backgroundtask.www.BackgroundTaskListener

All Implemented Interfaces:

java.util.EventListener, javax.servlet.ServletContextListener

public abstract class BackgroundTaskListener
extends java.lang.Object
implements javax.servlet.ServletContextListener

BackgroundTaskListener is responsible for initialization and starting of tasks which in background, that is without user interaction, periodically execute some functionality. This class is useful for starting such tasks in web environment when the application is running as managed application on the application server and therefore it's lifecycle is controlled by the application server.

Version:

$Id: BackgroundTaskListener.java,v 1.9 2007/01/07 06:15:34 bastafidli Exp $

Author:

Miro Halas

Code reviewer:

Miro Halas

Code reviewed:

1.6 2006/04/20 13:59:45 bastafidli

Field Summary

protected java.util.Map	m_tasks Map with all tasks created by this listener.
protected java.util.Map	m_tasksTimers Timer which periodically execute receiver tasks threads.

Constructor Summary

BackgroundTaskListener()
Creates a new instance of FileProcessorListener

Method Summary

void	contextDestroyed(javax.servlet.ServletContextEvent servletContextEvent)
void	contextInitialized(javax.servlet.ServletContextEvent servletContextEvent)
protected abstract BackgroundTask	createTask(int iId) Create task with given id.
protected abstract java.lang.String	getBaseProperty() Get base property which will be used to construct identification of the task.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

m_tasks

protected java.util.Map m_tasks

Map with all tasks created by this listener. Key is task name read from properties, value is BackgroundTask derived object for this name.

m_tasksTimers

protected java.util.Map m_tasksTimers

Timer which periodically execute receiver tasks threads. Key is task name, value is task timer.

Constructor Detail

BackgroundTaskListener

public BackgroundTaskListener()

Creates a new instance of FileProcessorListener

Method Detail

contextInitialized

public void contextInitialized(javax.servlet.ServletContextEvent servletContextEvent)

Specified by:

contextInitialized in interface javax.servlet.ServletContextListener

contextDestroyed

public void contextDestroyed(javax.servlet.ServletContextEvent servletContextEvent)

Specified by:

contextDestroyed in interface javax.servlet.ServletContextListener

createTask

protected abstract BackgroundTask createTask(int iId)
                                      throws org.opensubsystems.core.error.OSSException

Create task with given id. Derived class will implement this by creation of specific task based on the business logic of the derived class.

Parameters:

iId - - id of the task to create

Returns:

BackgroundTask - newly created task

Throws:

org.opensubsystems.core.error.OSSException - - error during creation of task

getBaseProperty

protected abstract java.lang.String getBaseProperty()

Get base property which will be used to construct identification of the task. The identification of task will be property.X where X goes sequentially from 0 to x and can have value 1 for enabled task or 0 for disabled task.

Returns:

String - name of the base property for task