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/*******************************************************************************
* Copyright (c) 2005, 2007 IBM Corporation 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
/*
* Created on Oct 26, 2004
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package org.eclipse.wst.common.internal.emf;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.jobs.ILock;
import org.eclipse.emf.common.notify.Notification;
import org.eclipse.emf.common.notify.Notifier;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.wst.common.internal.emf.utilities.ResourceIsLoadingAdapter;
/**
* The ResourceSynchronizedIsLoadingAdapter is used to synchronize the loading
* of EMF resources. This is the Eclipse version of ResourceIsLoadingAdapter,
* and uses the Eclipse ILock technology to acquire a semaphore until the
* Resource is loaded. the waitForResourceToLoad() method will pause until
* either (a) the Resource has loaded, the Adapter is notified, and the
* semaphore is released or (b) the DELAY timeout is exceeded, which prevents
* full deadlock.
*
* @author mdelder
*/
public class ResourceSynchronizedIsLoadingAdapter extends ResourceIsLoadingAdapter {
private final ILock loadingLock;
/**
* The delay is default to 5 minutes. This is the upward threshhold. The
* lock will wait up to DELAY milliseconds to acquire the lock, and bail
* if not. It does not mean that it will wait DELAY milliseconds always.
* In general, the wait should be almost instanteous -- just as long as
* document loading remains speedy.
*/
private static final long DELAY = 300000;
public ResourceSynchronizedIsLoadingAdapter() {
loadingLock = Platform.getJobManager().newLock();
if (loadingLock != null)
loadingLock.acquire();
}
/*
* (non-Javadoc)
*
* @see com.ibm.wtp.internal.emf.utilities.ResourceIsLoadingAdapter#waitForResourceToLoad()
*/
public void waitForResourceToLoad() {
if (loadingLock == null)
return;
boolean lockAcquired = false;
try {
if (loadingLock != null)
if (!(lockAcquired = loadingLock.acquire(DELAY)))
logWarning();
}
catch (InterruptedException e) {
// ignore, just continue
}
finally {
if (lockAcquired)
loadingLock.release();
}
}
/**
*
*/
private void logWarning() {
Notifier target = getTarget();
if (target == null || !(target instanceof Resource)) {
Resource resource = (Resource) target;
System.err.println("[WARNING] Could not acquire Semaphore Lock for Resource: \"" + resource.getURI() + "\" in " + getClass());
}
}
/*
* (non-Javadoc)
*
* @see com.ibm.wtp.internal.emf.utilities.ResourceIsLoadingAdapter#notifyChanged(org.eclipse.emf.common.notify.Notification)
*/
public void notifyChanged(Notification notification) {
if (notification.getNotifier() != null) {
// listen for the remove of the loading adapter
if (isSetLoadedResourceNotification(notification)) {
if (loadingLock != null)
loadingLock.release();
removeIsLoadingSupport();
}
}
}
/*
* (non-Javadoc)
*
* @see com.ibm.wtp.internal.emf.utilities.ResourceIsLoadingAdapter#forceRelease()
*/
public void forceRelease() {
if (loadingLock != null && loadingLock.getDepth() > 0)
loadingLock.release();
}
}
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