/* ********************************************************************** **
** Copyright notice **
** **
** (c) 2005-2009 RSSOwl Development Team **
** http://www.rssowl.org/ **
** **
** All rights reserved **
** **
** This program and the accompanying materials are made available under **
** the terms of the Eclipse Public License v1.0 which accompanies this **
** distribution, and is available at: **
** http://www.rssowl.org/legal/epl-v10.html **
** **
** A copy is found in the file epl-v10.html and important notices to the **
** license from the team is found in the textfile LICENSE.txt distributed **
** in this package. **
** **
** This copyright notice MUST APPEAR in all copies of the file! **
** **
** Contributors: **
** RSSOwl Development Team - initial API and implementation **
** **
** ********************************************************************** */
package org.rssowl.ui.internal.util;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.ui.progress.UIJob;
import org.rssowl.core.util.ITask;
/**
* The JobTracker guarantees that at anytime only the most recent
* <code>ITask</code> is executed.
*
* @author bpasero
*/
public class JobTracker {
private final int fDelay;
private final boolean fShowProgress;
private final boolean fRunInUIThread;
private Job fJob;
private ITask fTask;
private volatile boolean fRunning;
/**
* Creates a new JobTracker with the given Delay. The JobTracker guarantees
* that at anytime only the most recent <code>ITask</code> is executed.
*
* @param delay The delay in milliseconds after which new Tasks should be
* scheduled.
* @param showProgress if <code>TRUE</code>, progress is shown in the Progress
* View.
* @param priority The Priority of the <code>ITask</code>s that are to be run
* by this tracker.
*/
public JobTracker(int delay, boolean showProgress, ITask.Priority priority) {
this(delay, showProgress, false, priority);
}
/**
* Creates a new JobTracker with the given Delay. The JobTracker guarantees
* that at anytime only the most recent <code>ITask</code> is executed.
*
* @param delay The delay in milliseconds after which new Tasks should be
* scheduled.
* @param showProgress if <code>TRUE</code>, progress is shown in the Progress
* View.
* @param runInUIThread if <code>TRUE</code>, this Job will run in the
* UI-Thread by creating a <code>UIJob</code>.
* @param priority The Priority of the <code>ITask</code>s that are to be run
* by this tracker.
*/
public JobTracker(int delay, boolean showProgress, boolean runInUIThread, ITask.Priority priority) {
fDelay = delay;
fShowProgress = showProgress;
fRunInUIThread = runInUIThread;
createJob(priority);
}
/**
* Get the Delay after which Jobs should be scheduled for any new Tasks.
*
* @return Returns the Delay after which Jobs should be scheduled for any new
* given Tasks.
*/
public int getDelay() {
return fDelay;
}
/**
* Runs the given task after a certain delay that can be configured for this
* Tracker. Any previous Task that the Tracker scheduled is canceld first, if
* it was not yet running.
*
* @param task An instanceof <code>ITask</code> to be scheduled after the
* Delay that has been set for this Tracker.
*/
public void run(final ITask task) {
/* Cancel any other JobTracker of this Family first */
cancel();
/* Set current Task */
fTask = task;
/* Schedule with Delay */
fRunning = true;
fJob.schedule(getDelay());
}
private void createJob(ITask.Priority priority) {
/* Create a UI-Job */
if (fRunInUIThread) {
fJob = new UIJob("") { //$NON-NLS-1$
@Override
public IStatus runInUIThread(IProgressMonitor monitor) {
try {
if (!monitor.isCanceled() && fTask != null)
return fTask.run(monitor);
return Status.CANCEL_STATUS;
} finally {
fRunning = false;
}
}
@Override
public boolean belongsTo(Object family) {
return family == JobTracker.this;
}
};
}
/* Create a Normal Job */
else {
fJob = new Job("") { //$NON-NLS-1$
@Override
protected IStatus run(IProgressMonitor monitor) {
try {
if (!monitor.isCanceled() && fTask != null)
return fTask.run(monitor);
return Status.CANCEL_STATUS;
} finally {
fRunning = false;
}
}
@Override
public boolean belongsTo(Object family) {
return family == JobTracker.this;
}
};
}
/* Make it a System Job if required */
if (!fShowProgress)
fJob.setSystem(true);
/* Apply Priority */
if (priority == ITask.Priority.INTERACTIVE)
fJob.setPriority(Job.INTERACTIVE);
else if (priority == ITask.Priority.SHORT)
fJob.setPriority(Job.SHORT);
}
/** Cancels any Task that did not yet run. */
public void cancel() {
/* First check if actually running */
if (!fRunning)
return;
/* Cancel */
Job.getJobManager().cancel(this);
fRunning = false;
}
/**
* @return <code>true</code> if the JobTracker has a {@link ITask} pending to
* run and <code>false</code> otherwise.
*/
public boolean isRunning() {
return fRunning;
}
}