/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
* by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
*
* Copyright 2008 Sun Microsystems, Inc.
*/
package org.opends.guitools.controlpanel.util;
/**
* This class provides a mechanism for running a task in the background using a
* separate thread and providing the caller with notification when it has
* completed.
* @param <T> type of object returned by this process
*/
public abstract class BackgroundTask<T>
{
private BackgroundTaskThread<T> taskThread;
private boolean interrupted;
/**
* Creates a new thread and begins running the task in the background. When
* the task has completed, the {@code backgroundTaskCompleted} method will be
* invoked.
*/
public final void startBackgroundTask()
{
interrupted = false;
taskThread = new BackgroundTaskThread<T>(this);
taskThread.start();
}
/**
* Interrupts the thread that is running background.
*
*/
public final void interrupt()
{
interrupted = true;
if (taskThread != null)
{
taskThread.interrupt();
}
}
/**
* Returns <CODE>true</CODE> if the thread running in the background is
* interrupted and <CODE>false</CODE> otherwise.
* @return <CODE>true</CODE> if the thread running in the background is
* interrupted and <CODE>false</CODE> otherwise.
*/
public boolean isInterrupted()
{
return interrupted;
}
/**
* Performs all processing associated with the task.
*
* @return An {@code Object} with information about the processing performed
* for this task, or {@code null} if no return value is needed.
*
* @throws Throwable throwable that will be passed through the method
* backgroundTaskCompleted.
*/
public abstract T processBackgroundTask() throws Throwable;
/**
* This method will be invoked to indicate that the background task has
* completed. If processing completed successfully, then the
* {@code Throwable} argument will be {@code null} and the {@code returnValue}
* argument will contain the value returned by the
* {@code processBackgroundTask} method. If an exception or error was thrown,
* then the {@code throwable} argument will not be {@code null}.
*
* @param returnValue The value returned by the
* {@code processBackgroundTask} method when processing
* completed, or {@code null} if no value was returned or
* an exception was encountered during processing.
* @param throwable A {@code Throwable} instance (e.g., an exception) that
* was raised during processing, or {@code null} if all
* processing completed successfully.
*/
public abstract void backgroundTaskCompleted(T returnValue,
Throwable throwable);
}