bundles/org.eclipse.equinox.registry/src/org/eclipse/equinox/registry/tracker/ExtensionTracker.java - equinox/rt.equinox.bundles - Git at Google

 /*******************************************************************************
  * Copyright (c) 2004, 2005 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
  *******************************************************************************/
 package org.eclipse.equinox.registry.tracker;

 import java.util.HashMap;
 import java.util.Map;
 import org.eclipse.core.internal.registry.RegistryMessages;
 import org.eclipse.core.internal.registry.osgi.Activator;
 import org.eclipse.core.internal.runtime.ReferenceHashSet;
 import org.eclipse.core.internal.runtime.RuntimeLog;
 import org.eclipse.core.runtime.*;
 import org.eclipse.equinox.registry.*;
 import org.osgi.framework.BundleContext;
 import org.osgi.util.tracker.ServiceTracker;

 /**
  * Implementation of the IExtensionTracker.
  * @see org.eclipse.equinox.registry.tracker.IExtensionTracker
  * @since 3.1
  */
 public class ExtensionTracker implements IExtensionTracker, IRegistryChangeListener {
 	//Map keeping the association between extensions and a set of objects. Key: IExtension, value: ReferenceHashSet.
 	private Map extensionToObjects = new HashMap();
 	private ListenerList handlers = new ListenerList();
 	private final Object lock = new Object();
 	private boolean closed = false;
 	IExtensionRegistry registry; // the registry that this tacker works with

 	private static final Object[] EMPTY_ARRAY = new Object[0];

 	/**
 	 * Construct a new instance of the extension tracker.
 	 */
 	public ExtensionTracker() {
 		BundleContext context = Activator.getContext();
 		ServiceTracker registryTracker = new ServiceTracker(context, IExtensionRegistry.class.getName(), null);
 		registryTracker.open(true); // TODO check if argument is necessary
 		if (registryTracker != null) {
 			registry = (IExtensionRegistry) registryTracker.getService();
 			registry.addRegistryChangeListener(this);
 			registryTracker.close();
 		} else
 			RuntimeLog.log(new Status(IStatus.ERROR, RegistryMessages.OWNER_NAME, 0, RegistryMessages.registry_no_default, null));
 	}

 	/**
 	 * Construct a new instance of the extension tracker.
 	 * @param theRegistry - the extension registry containing tracked extensions and extension points.
 	 */
 	public ExtensionTracker(IExtensionRegistry theRegistry) {
 		registry = theRegistry;
 		if (registry != null)
 			registry.addRegistryChangeListener(this);
 	}

 	/* (non-Javadoc)
 	 * @see IExtensionTracker@registerHandler(IExtensionChangeHandler, IFilter)
 	 */
 	public void registerHandler(IExtensionChangeHandler handler, IFilter filter) {
 		synchronized (lock) {
 			if (closed)
 				return;
 			// TODO need to store the filter with the handler
 			handlers.add(new HandlerWrapper(handler, filter));
 		}
 	}

 	/* (non-Javadoc)
 	 * @see IExtensionTracker@unregisterHandler(IExtensionChangeHandler)
 	 */
 	public void unregisterHandler(IExtensionChangeHandler handler) {
 		synchronized (lock) {
 			if (closed)
 				return;
 			handlers.remove(new HandlerWrapper(handler, null));
 		}
 	}

 	/* (non-Javadoc)
 	 * @see IExtensionTracker@registerObject(IExtension, Object, int)
 	 */
 	public void registerObject(IExtension element, Object object, int referenceType) {
 		if (element == null || object == null)
 			return;

 		synchronized (lock) {
 			if (closed)
 				return;

 			ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.get(element);
 			if (associatedObjects == null) {
 				associatedObjects = new ReferenceHashSet();
 				extensionToObjects.put(element, associatedObjects);
 			}
 			associatedObjects.add(object, referenceType);
 		}
 	}

 	/**
 	 * Implementation of IRegistryChangeListener interface.  This method must not
 	 * be called by clients.
 	 */
 	public void registryChanged(IRegistryChangeEvent event) {
 		IExtensionDelta delta[] = event.getExtensionDeltas();
 		int len = delta.length;
 		for (int i = 0; i < len; i++)
 			switch (delta[i].getKind()) {
 				case IExtensionDelta.ADDED :
 					doAdd(delta[i]);
 					break;
 				case IExtensionDelta.REMOVED :
 					doRemove(delta[i]);
 					break;
 				default :
 					break;
 			}
 	}

 	/**
 	 * Notify all handlers whose filter matches that the given delta occured
 	 * If the list of objects is not null then this is a removal and the handlers
 	 * will be given a chance to process the list.  If it is null then the notification is
 	 * an addition.
 	 * @param delta the change to broadcast
 	 * @param objects the objects to pass to the handlers on removals
 	 */
 	private void notify(IExtensionDelta delta, Object[] objects) {
 		// Get a copy of the handlers for safe notification
 		Object[] handlersCopy = null;
 		synchronized (lock) {
 			if (closed)
 				return;

 			if (handlers == null || handlers.isEmpty())
 				return;
 			handlersCopy = handlers.getListeners();
 		}

 		for (int i = 0; i < handlersCopy.length; i++) {
 			HandlerWrapper wrapper = (HandlerWrapper) handlersCopy[i];
 			if (wrapper.filter == null || wrapper.filter.matches(delta.getExtensionPoint())) {
 				if (objects == null)
 					applyAdd(wrapper.handler, delta.getExtension());
 				else
 					applyRemove(wrapper.handler, delta.getExtension(), objects);
 			}
 		}
 	}

 	protected void applyAdd(IExtensionChangeHandler handler, IExtension extension) {
 		handler.addExtension(this, extension);
 	}

 	private void doAdd(IExtensionDelta delta) {
 		notify(delta, null);
 	}

 	private void doRemove(IExtensionDelta delta) {
 		Object[] removedObjects = null;
 		synchronized (lock) {
 			if (closed)
 				return;

 			ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.remove(delta.getExtension());
 			if (associatedObjects == null)
 				return;
 			//Copy the objects early so we don't hold the lock too long
 			removedObjects = associatedObjects.toArray();
 		}
 		notify(delta, removedObjects);
 	}

 	protected void applyRemove(IExtensionChangeHandler handler, IExtension removedExtension, Object[] removedObjects) {
 		handler.removeExtension(removedExtension, removedObjects);
 	}

 	/* (non-Javadoc)
 	 * @see IExtensionTracker@getObjects(IExtension)
 	 */
 	public Object[] getObjects(IExtension element) {
 		synchronized (lock) {
 			if (closed)
 				return EMPTY_ARRAY;
 			ReferenceHashSet objectSet = (ReferenceHashSet) extensionToObjects.get(element);
 			if (objectSet == null)
 				return EMPTY_ARRAY;

 			return objectSet.toArray();
 		}
 	}

 	/* (non-Javadoc)
 	 * @see IExtensionTracker@close()
 	 */
 	public void close() {
 		synchronized (lock) {
 			if (closed)
 				return;
 			if (registry != null)
 				registry.removeRegistryChangeListener(this);
 			extensionToObjects = null;
 			handlers = null;

 			closed = true;
 		}
 	}

 	/* (non-Javadoc)
 	 * @see IExtensionTracker@unregisterObject(IExtension, Object)
 	 */
 	public void unregisterObject(IExtension extension, Object object) {
 		synchronized (lock) {
 			if (closed)
 				return;
 			ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.get(extension);
 			if (associatedObjects != null)
 				associatedObjects.remove(object);
 		}
 	}

 	/* (non-Javadoc)
 	 * @see IExtensionTracker@unregisterObject(IExtension)
 	 */
 	public Object[] unregisterObject(IExtension extension) {
 		synchronized (lock) {
 			if (closed)
 				return EMPTY_ARRAY;
 			ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.remove(extension);
 			if (associatedObjects == null)
 				return EMPTY_ARRAY;
 			return associatedObjects.toArray();
 		}
 	}

 	/**
 	 * Return an instance of filter matching all changes for the given extension point.
 	 * @param xpt the extension point
 	 * @return a filter
 	 */
 	public static IFilter createExtensionPointFilter(final IExtensionPoint xpt) {
 		return new IFilter() {
 			public boolean matches(IExtensionPoint target) {
 				return xpt.equals(target);
 			}
 		};
 	}

 	/**
 	 * Return an instance of filter matching all changes for the given extension points.
 	 * @param xpts the extension points used to filter
 	 * @return a filter
 	 */
 	public static IFilter createExtensionPointFilter(final IExtensionPoint[] xpts) {
 		return new IFilter() {
 			public boolean matches(IExtensionPoint target) {
 				for (int i = 0; i < xpts.length; i++)
 					if (xpts[i].equals(target))
 						return true;
 				return false;
 			}
 		};
 	}

 	/**
 	 * Return an instance of filter matching all changes from a given plugin.
 	 * @param id the plugin id
 	 * @return a filter
 	 */
 	public static IFilter createNamespaceFilter(final String id) {
 		return new IFilter() {
 			public boolean matches(IExtensionPoint target) {
 				return id.equals(target.getNamespace());
 			}
 		};
 	}

 	private class HandlerWrapper {
 		IExtensionChangeHandler handler;
 		IFilter filter;

 		public HandlerWrapper(IExtensionChangeHandler handler, IFilter filter) {
 			this.handler = handler;
 			this.filter = filter;
 		}

 		public boolean equals(Object target) {
 			return handler.equals(((HandlerWrapper) target).handler);
 		}

 		public int hashCode() {
 			return handler.hashCode();
 		}
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2004, 2005 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
	*******************************************************************************/
	package org.eclipse.equinox.registry.tracker;

	import java.util.HashMap;
	import java.util.Map;
	import org.eclipse.core.internal.registry.RegistryMessages;
	import org.eclipse.core.internal.registry.osgi.Activator;
	import org.eclipse.core.internal.runtime.ReferenceHashSet;
	import org.eclipse.core.internal.runtime.RuntimeLog;
	import org.eclipse.core.runtime.*;
	import org.eclipse.equinox.registry.*;
	import org.osgi.framework.BundleContext;
	import org.osgi.util.tracker.ServiceTracker;

	/**
	* Implementation of the IExtensionTracker.
	* @see org.eclipse.equinox.registry.tracker.IExtensionTracker
	* @since 3.1
	*/
	public class ExtensionTracker implements IExtensionTracker, IRegistryChangeListener {
	//Map keeping the association between extensions and a set of objects. Key: IExtension, value: ReferenceHashSet.
	private Map extensionToObjects = new HashMap();
	private ListenerList handlers = new ListenerList();
	private final Object lock = new Object();
	private boolean closed = false;
	IExtensionRegistry registry; // the registry that this tacker works with

	private static final Object[] EMPTY_ARRAY = new Object[0];

	/**
	* Construct a new instance of the extension tracker.
	*/
	public ExtensionTracker() {
	BundleContext context = Activator.getContext();
	ServiceTracker registryTracker = new ServiceTracker(context, IExtensionRegistry.class.getName(), null);
	registryTracker.open(true); // TODO check if argument is necessary
	if (registryTracker != null) {
	registry = (IExtensionRegistry) registryTracker.getService();
	registry.addRegistryChangeListener(this);
	registryTracker.close();
	} else
	RuntimeLog.log(new Status(IStatus.ERROR, RegistryMessages.OWNER_NAME, 0, RegistryMessages.registry_no_default, null));
	}

	/**
	* Construct a new instance of the extension tracker.
	* @param theRegistry - the extension registry containing tracked extensions and extension points.
	*/
	public ExtensionTracker(IExtensionRegistry theRegistry) {
	registry = theRegistry;
	if (registry != null)
	registry.addRegistryChangeListener(this);
	}

	/* (non-Javadoc)
	* @see IExtensionTracker@registerHandler(IExtensionChangeHandler, IFilter)
	*/
	public void registerHandler(IExtensionChangeHandler handler, IFilter filter) {
	synchronized (lock) {
	if (closed)
	return;
	// TODO need to store the filter with the handler
	handlers.add(new HandlerWrapper(handler, filter));
	}
	}

	/* (non-Javadoc)
	* @see IExtensionTracker@unregisterHandler(IExtensionChangeHandler)
	*/
	public void unregisterHandler(IExtensionChangeHandler handler) {
	synchronized (lock) {
	if (closed)
	return;
	handlers.remove(new HandlerWrapper(handler, null));
	}
	}

	/* (non-Javadoc)
	* @see IExtensionTracker@registerObject(IExtension, Object, int)
	*/
	public void registerObject(IExtension element, Object object, int referenceType) {
	if (element == null \|\| object == null)
	return;

	synchronized (lock) {
	if (closed)
	return;

	ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.get(element);
	if (associatedObjects == null) {
	associatedObjects = new ReferenceHashSet();
	extensionToObjects.put(element, associatedObjects);
	}
	associatedObjects.add(object, referenceType);
	}
	}

	/**
	* Implementation of IRegistryChangeListener interface. This method must not
	* be called by clients.
	*/
	public void registryChanged(IRegistryChangeEvent event) {
	IExtensionDelta delta[] = event.getExtensionDeltas();
	int len = delta.length;
	for (int i = 0; i < len; i++)
	switch (delta[i].getKind()) {
	case IExtensionDelta.ADDED :
	doAdd(delta[i]);
	break;
	case IExtensionDelta.REMOVED :
	doRemove(delta[i]);
	break;
	default :
	break;
	}
	}

	/**
	* Notify all handlers whose filter matches that the given delta occured
	* If the list of objects is not null then this is a removal and the handlers
	* will be given a chance to process the list. If it is null then the notification is
	* an addition.
	* @param delta the change to broadcast
	* @param objects the objects to pass to the handlers on removals
	*/
	private void notify(IExtensionDelta delta, Object[] objects) {
	// Get a copy of the handlers for safe notification
	Object[] handlersCopy = null;
	synchronized (lock) {
	if (closed)
	return;

	if (handlers == null \|\| handlers.isEmpty())
	return;
	handlersCopy = handlers.getListeners();
	}

	for (int i = 0; i < handlersCopy.length; i++) {
	HandlerWrapper wrapper = (HandlerWrapper) handlersCopy[i];
	if (wrapper.filter == null \|\| wrapper.filter.matches(delta.getExtensionPoint())) {
	if (objects == null)
	applyAdd(wrapper.handler, delta.getExtension());
	else
	applyRemove(wrapper.handler, delta.getExtension(), objects);
	}
	}
	}

	protected void applyAdd(IExtensionChangeHandler handler, IExtension extension) {
	handler.addExtension(this, extension);
	}

	private void doAdd(IExtensionDelta delta) {
	notify(delta, null);
	}

	private void doRemove(IExtensionDelta delta) {
	Object[] removedObjects = null;
	synchronized (lock) {
	if (closed)
	return;

	ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.remove(delta.getExtension());
	if (associatedObjects == null)
	return;
	//Copy the objects early so we don't hold the lock too long
	removedObjects = associatedObjects.toArray();
	}
	notify(delta, removedObjects);
	}

	protected void applyRemove(IExtensionChangeHandler handler, IExtension removedExtension, Object[] removedObjects) {
	handler.removeExtension(removedExtension, removedObjects);
	}

	/* (non-Javadoc)
	* @see IExtensionTracker@getObjects(IExtension)
	*/
	public Object[] getObjects(IExtension element) {
	synchronized (lock) {
	if (closed)
	return EMPTY_ARRAY;
	ReferenceHashSet objectSet = (ReferenceHashSet) extensionToObjects.get(element);
	if (objectSet == null)
	return EMPTY_ARRAY;

	return objectSet.toArray();
	}
	}

	/* (non-Javadoc)
	* @see IExtensionTracker@close()
	*/
	public void close() {
	synchronized (lock) {
	if (closed)
	return;
	if (registry != null)
	registry.removeRegistryChangeListener(this);
	extensionToObjects = null;
	handlers = null;

	closed = true;
	}
	}

	/* (non-Javadoc)
	* @see IExtensionTracker@unregisterObject(IExtension, Object)
	*/
	public void unregisterObject(IExtension extension, Object object) {
	synchronized (lock) {
	if (closed)
	return;
	ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.get(extension);
	if (associatedObjects != null)
	associatedObjects.remove(object);
	}
	}

	/* (non-Javadoc)
	* @see IExtensionTracker@unregisterObject(IExtension)
	*/
	public Object[] unregisterObject(IExtension extension) {
	synchronized (lock) {
	if (closed)
	return EMPTY_ARRAY;
	ReferenceHashSet associatedObjects = (ReferenceHashSet) extensionToObjects.remove(extension);
	if (associatedObjects == null)
	return EMPTY_ARRAY;
	return associatedObjects.toArray();
	}
	}

	/**
	* Return an instance of filter matching all changes for the given extension point.
	* @param xpt the extension point
	* @return a filter
	*/
	public static IFilter createExtensionPointFilter(final IExtensionPoint xpt) {
	return new IFilter() {
	public boolean matches(IExtensionPoint target) {
	return xpt.equals(target);
	}
	};
	}

	/**
	* Return an instance of filter matching all changes for the given extension points.
	* @param xpts the extension points used to filter
	* @return a filter
	*/
	public static IFilter createExtensionPointFilter(final IExtensionPoint[] xpts) {
	return new IFilter() {
	public boolean matches(IExtensionPoint target) {
	for (int i = 0; i < xpts.length; i++)
	if (xpts[i].equals(target))
	return true;
	return false;
	}
	};
	}

	/**
	* Return an instance of filter matching all changes from a given plugin.
	* @param id the plugin id
	* @return a filter
	*/
	public static IFilter createNamespaceFilter(final String id) {
	return new IFilter() {
	public boolean matches(IExtensionPoint target) {
	return id.equals(target.getNamespace());
	}
	};
	}

	private class HandlerWrapper {
	IExtensionChangeHandler handler;
	IFilter filter;

	public HandlerWrapper(IExtensionChangeHandler handler, IFilter filter) {
	this.handler = handler;
	this.filter = filter;
	}

	public boolean equals(Object target) {
	return handler.equals(((HandlerWrapper) target).handler);
	}

	public int hashCode() {
	return handler.hashCode();
	}
	}

	}