/*******************************************************************************
* Copyright (c) 2009 Tasktop Technologies and others.
* 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.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Tasktop Technologies - initial API and implementation
*******************************************************************************/
package org.eclipse.mylyn.internal.tasks.core.sync;
import java.util.HashMap;
import org.eclipse.core.runtime.jobs.IJobChangeEvent;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.core.runtime.jobs.JobChangeAdapter;
/**
* @author Steffen Pingel
*/
public class SynchronizationScheduler {
public static abstract class Synchronizer<T extends Job> {
private boolean pendingRequest;
public abstract T createJob();
}
public HashMap<Object, Synchronizer<?>> synchronizerByObject;
public SynchronizationScheduler() {
synchronizerByObject = new HashMap<Object, Synchronizer<?>>();
}
public void schedule(final Object object, final Synchronizer<?> synchronizer) {
synchronized (synchronizerByObject) {
Synchronizer<?> running = synchronizerByObject.get(object);
if (running != null) {
running.pendingRequest = true;
return;
} else {
synchronizerByObject.put(object, synchronizer);
}
}
scheduleJob(object, synchronizer);
}
private void scheduleJob(final Object object, final Synchronizer<?> synchronizer) {
final Job job = synchronizer.createJob();
final JobChangeAdapter listener = new JobChangeAdapter() {
@Override
public void done(IJobChangeEvent event) {
job.removeJobChangeListener(this);
boolean reschedule;
synchronized (synchronizerByObject) {
reschedule = synchronizer.pendingRequest;
if (synchronizer.pendingRequest) {
synchronizer.pendingRequest = false;
} else {
synchronizerByObject.remove(object);
}
}
if (reschedule) {
scheduleJob(object, synchronizer);
}
}
};
job.addJobChangeListener(listener);
job.schedule();
}
public void cancel(Object object) {
synchronized (synchronizerByObject) {
Synchronizer<?> running = synchronizerByObject.get(object);
if (running != null) {
running.pendingRequest = false;
}
}
}
}