bundles/org.eclipse.team.core/src/org/eclipse/team/core/synchronize/SyncInfoSet.java - gerrit/platform/eclipse.platform.team - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2003 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.team.core.synchronize;

 import java.util.*;

 import org.eclipse.core.resources.IResource;
 import org.eclipse.core.resources.IWorkspaceRunnable;
 import org.eclipse.core.runtime.*;
 import org.eclipse.core.runtime.jobs.ILock;
 import org.eclipse.team.core.ITeamStatus;
 import org.eclipse.team.core.TeamStatus;
 import org.eclipse.team.core.synchronize.FastSyncInfoFilter.SyncInfoDirectionFilter;
 import org.eclipse.team.internal.core.*;
 import org.eclipse.team.internal.core.subscribers.SyncInfoStatistics;
 import org.eclipse.team.internal.core.subscribers.SyncSetChangedEvent;

 /**
  * A dynamic collection of {@link SyncInfo} objects that provides
  * change notification to registered listeners. Batching of change notifications
  * can be accomplished using the <code>beginInput/endInput</code> methods.
  * @see SyncInfoTree
  * @see SyncInfo
  * @see ISyncInfoSetChangeListener
  * @since 3.0
  */
 public class SyncInfoSet {
 	// fields used to hold resources of interest
 	// {IPath -> SyncInfo}
 	private Map resources = Collections.synchronizedMap(new HashMap());

 	// keep track of number of sync kinds in the set
 	private SyncInfoStatistics statistics = new SyncInfoStatistics();

 	// keep track of errors that occurred while trying to populate the set
 	private Map errors = new HashMap();

 	private boolean lockedForModification;

 	/**
 	 * Create an empty set.
 	 */
 	public SyncInfoSet() {
 	}

 	/**
 	 * Create a <code>SyncInfoSet</code> containing the given <code>SyncInfo</code>
 	 * instances
 	 * @param infos the <code>SyncInfo</code> instances to be contained by this set
 	 */
 	public SyncInfoSet(SyncInfo[] infos) {
 		this();
 		// use the internal add since we can't have listeners at this point anyway
 		for (int i = 0; i < infos.length; i++) {
 			internalAdd(infos[i]);
 		}
 	}

 	/**
 	 * Return an array of <code>SyncInfo</code> for all out-of-sync resources that are contained by the set.
 	 * @return an array of <code>SyncInfo</code>
 	 */
 	public synchronized SyncInfo[] getSyncInfos() {
 		return (SyncInfo[]) resources.values().toArray(new SyncInfo[resources.size()]);
 	}

 	/**
 	 * Return all out-of-sync resources contained in this set. The default implementation
 	 * uses <code>getSyncInfos()</code> to determine the resources contained in the set.
 	 * Subclasses may override to optimize.
 	 * @return all out-of-sync resources contained in the set
 	 */
 	public IResource[] getResources() {
 		SyncInfo[] infos = getSyncInfos();
 		List resources = new ArrayList();
 		for (int i = 0; i < infos.length; i++) {
 			SyncInfo info = infos[i];
 			resources.add(info.getLocal());
 		}
 		return (IResource[]) resources.toArray(new IResource[resources.size()]);
 	}

 	/**
 	 * Return the <code>SyncInfo</code> for the given resource or <code>null</code>
 	 * if the resource is not contained in the set.
 	 * @param resource the resource
 	 * @return the <code>SyncInfo</code> for the resource or <code>null</code>
 	 */
 	public synchronized SyncInfo getSyncInfo(IResource resource) {
 		return (SyncInfo)resources.get(resource.getFullPath());
 	}

 	/**
 	 * Return the number of out-of-sync resources contained in this set.
 	 * @return the size of the set.
 	 */
 	public synchronized int size() {
 		return resources.size();
 	}

 	/**
 	 * Return the number of out-of-sync resources in the given set whose sync kind
 	 * matches the given kind and mask (e.g. <code>(SyncInfo#getKind() & mask) == kind</code>).
 	 * @param kind the sync kind
 	 * @param mask the sync kind mask
 	 * @return the number of matching resources in the set.
 	 */
 	public long countFor(int kind, int mask) {
 		return statistics.countFor(kind, mask);
 	}

 	/**
 	 * Returns <code>true</code> if there are any conflicting nodes in the set, and
 	 * <code>false</code> otherwise.
 	 */
 	public boolean hasConflicts() {
 		return countFor(SyncInfo.CONFLICTING, SyncInfo.DIRECTION_MASK) > 0;
 	}

 	/**
 	 * Return whether the set is empty.
 	 * @return <code>true</code> if the set is empty
 	 */
 	public synchronized boolean isEmpty() {
 		return resources.isEmpty();
 	}

 	/**
 	 * Add the <code>SyncInfo</code> to the set, replacing any previously existing one.
 	 * @param info the new <code>SyncInfo</code>
 	 */
 	protected synchronized void internalAdd(SyncInfo info) {
 		Assert.isTrue(!lockedForModification);
 		IResource local = info.getLocal();
 		IPath path = local.getFullPath();
 		SyncInfo oldSyncInfo = (SyncInfo)resources.put(path, info);
 		if(oldSyncInfo == null) {
 			statistics.add(info);
 		} else {
 			statistics.remove(oldSyncInfo);
 			statistics.add(info);
 		}
 	}

 	/**
 	 * Remove the resource from the set, updating all internal data structures.
 	 * @param resource the resource to be removed
 	 * @return the <code>SyncInfo</code> that was just removed
 	 */
 	protected synchronized SyncInfo internalRemove(IResource resource) {
 		Assert.isTrue(!lockedForModification);
 		IPath path = resource.getFullPath();
 		SyncInfo info = (SyncInfo)resources.remove(path);
 		if (info != null) {
 			statistics.remove(info);
 		}
 		return info;
 	}

 	/**
 	 * Registers the given listener for sync info set notifications. Has
 	 * no effect if an identical listener is already registered.
 	 *
 	 * @param listener listener to register
 	 */
 	public void addSyncSetChangedListener(ISyncInfoSetChangeListener listener) {
 		synchronized(listeners) {
 			listeners.add(listener);
 		}
 	}

 	/**
 	 * Deregisters the given listener for participant notifications. Has
 	 * no effect if listener is not already registered.
 	 *
 	 * @param listener listener to deregister
 	 */
 	public void removeSyncSetChangedListener(ISyncInfoSetChangeListener listener) {
 		synchronized(listeners) {
 			listeners.remove(listener);
 		}
 	}

 	/**
 	 * Reset the sync set so it is empty. Listeners are notified of the change.
 	 */
 	public void clear() {
 		try {
 			beginInput();
 			errors.clear();
 			resources.clear();
 			statistics.clear();
 			getChangeEvent().reset();
 		} finally {
 			endInput(null);
 		}
 	}

 	/*
 	 * Run the given runnable. This operation
 	 * will block other threads from modifying the
 	 * set and postpone any change notifications until after the runnable
 	 * has been executed. Mutable subclasses must override.
 	 * <p>
 	 * The given runnable may be run in the same thread as the caller or
 	 * more be run asynchronously in another thread at the discretion of the
 	 * subclass implementation. However, it is gaurenteed that two invocations
 	 * of <code>run</code> performed in the same thread will be executed in the
 	 * same order even if run in different threads.
 	 *
 	 * @param runnable a runnable
 	 * @param progress a progress monitor or <code>null</code>
 	 */
 	private void run(IWorkspaceRunnable runnable, IProgressMonitor monitor) {
 		monitor = Policy.monitorFor(monitor);
 		monitor.beginTask(null, 100);
 		try {
 			beginInput();
 			runnable.run(Policy.subMonitorFor(monitor, 80));
 		} catch (CoreException e) {
 			addError(new TeamStatus(IStatus.ERROR, TeamPlugin.ID, ITeamStatus.SYNC_INFO_SET_ERROR, e.getMessage(), e, null));
 		} finally {
 			endInput(Policy.subMonitorFor(monitor, 20));
 		}
 	}

 	/**
 	 * Connect the listener to the sync set in such a fashion that the listener will
 	 * be connected the the sync set using <code>addChangeListener</code>
 	 * and issued a reset event. This is done to provide a means of connecting to the
 	 * sync set and initializing a model based on the sync set without worrying about
 	 * missing events.
 	 * <p>
 	 * The reset event may be done in the context of this method invocation or may be
 	 * done in another thread at the discretion of the <code>SyncInfoSet</code>
 	 * implementation.
 	 * <p>
 	 * Disconnecting is done by calling <code>removeChangeListener</code>. Once disconnected,
 	 * a listener can reconnect to be reinitialized.
 	 * @param listener
 	 * @param monitor
 	 */
 	public void connect(final ISyncInfoSetChangeListener listener, IProgressMonitor monitor) {
 		run(new IWorkspaceRunnable() {
 			public void run(IProgressMonitor monitor) {
 				try {
 					monitor.beginTask(null, 100);
 					addSyncSetChangedListener(listener);
 					listener.syncInfoSetReset(SyncInfoSet.this, Policy.subMonitorFor(monitor, 95));
 				} finally {
 					monitor.done();
 				}
 			}
 		}, monitor);
 	}

 	private ILock lock = Platform.getJobManager().newLock();

 	private Set listeners = Collections.synchronizedSet(new HashSet());

 	private SyncSetChangedEvent changes = createEmptyChangeEvent();

 	/**
 	 * Add the given <code>SyncInfo</code> to the set. A change event will
 	 * be generated unless the call to this method is nested in between calls
 	 * to <code>beginInput()</code> and <code>endInput(IProgressMonitor)</code>
 	 * in which case the event for this addition and any other sync set
 	 * change will be fired in a batched event when <code>endInput</code>
 	 * is invoked.
 	 * Invoking this method outside of the above mentioned block will result
 	 * in the <code>endInput(IProgressMonitor)</code> being invoked with a null
 	 * progress monitor. If responsiveness is required, the client should always
 	 * nest sync set modifications within <code>beginInput/endInput</code>.
 	 * @param info
 	 */
 	public void add(SyncInfo info) {
 		try {
 			beginInput();
 			boolean alreadyExists = getSyncInfo(info.getLocal()) != null;
 			internalAdd(info);
 			if (alreadyExists) {
 				getChangeEvent().changed(info);
 			} else {
 				getChangeEvent().added(info);
 			}
 		} finally {
 			endInput(null);
 		}
 	}

 	/**
 	 * Add all the syncinfo from the given set to this set.
 	 * @param set the set whose sync info should be added to this set
 	 */
 	public void addAll(SyncInfoSet set) {
 		try {
 			beginInput();
 			SyncInfo[] infos = set.getSyncInfos();
 			for (int i = 0; i < infos.length; i++) {
 				add(infos[i]);
 			}
 		} finally {
 			endInput(null);
 		}
 	}

 	/**
 	 * Remove the given local resource from the set.
 	 * @param resource the local resource to remove
 	 */
 	public synchronized void remove(IResource resource) {
 		try {
 			beginInput();
 			SyncInfo info = internalRemove(resource);
 			getChangeEvent().removed(resource, info);
 		} finally {
 			endInput(null);
 		}
 	}

 	/**
 	 * Remove all the given resources from the set.
 	 * @param resources the resources to be removed
 	 */
 	public void removeAll(IResource[] resources) {
 		try {
 			beginInput();
 			for (int i = 0; i < resources.length; i++) {
 				remove(resources[i]);
 			}
 		} finally {
 			endInput(null);
 		}
 	}

 	/**
 	 * Removes all conflicting nodes from this set.
 	 */
 	public void removeConflictingNodes() {
 		rejectNodes(new SyncInfoDirectionFilter(SyncInfo.CONFLICTING));
 	}

 	/**
 	 * Removes all outgoing nodes from this set.
 	 */
 	public void removeOutgoingNodes() {
 		rejectNodes(new SyncInfoDirectionFilter(SyncInfo.OUTGOING));
 	}

 	/**
 	 * Removes all incoming nodes from this set.
 	 */
 	public void removeIncomingNodes() {
 		rejectNodes(new SyncInfoDirectionFilter(SyncInfo.INCOMING));
 	}

 	/**
 	 * Indicate whether the set has nodes matching the given filter.
 	 * @param filter a sync info filter
 	 */
 	public boolean hasNodes(FastSyncInfoFilter filter) {
 		SyncInfo[] infos = getSyncInfos();
 		for (int i = 0; i < infos.length; i++) {
 			SyncInfo info = infos[i];
 			if (info != null && filter.select(info)) {
 				return true;
 			}
 		}
 		return false;
 	}

 	/**
 	 * Removes all nodes from this set that do not match the given filter
 	 * leaving only those that do match the filter.
 	 * @param filter a sync info filter
 	 */
 	public void selectNodes(FastSyncInfoFilter filter) {
 		try {
 			beginInput();
 			SyncInfo[] infos = getSyncInfos();
 			for (int i = 0; i < infos.length; i++) {
 				SyncInfo info = infos[i];
 				if (info == null || !filter.select(info)) {
 					remove(info.getLocal());
 				}
 			}
 		} finally {
 			endInput(null);
 		}
 	}

 	/**
 	 * Removes all nodes from this set that match the given filter
 	 * leaving those that do not match the filter.
 	 * @param filter a sync info filter
 	 */
 	public void rejectNodes(FastSyncInfoFilter filter) {
 		try {
 			beginInput();
 			SyncInfo[] infos = getSyncInfos();
 			for (int i = 0; i < infos.length; i++) {
 				SyncInfo info = infos[i];
 				if (info != null && filter.select(info)) {
 					remove(info.getLocal());
 				}
 			}
 		} finally {
 			endInput(null);
 		}
 	}

 	/**
 	 * Return all nodes in this set that match the given filter.
 	 * @param filter a sync info filter
 	 */
 	public SyncInfo[] getNodes(FastSyncInfoFilter filter) {
 		List result = new ArrayList();
 		SyncInfo[] infos = getSyncInfos();
 		for (int i = 0; i < infos.length; i++) {
 			SyncInfo info = infos[i];
 			if (info != null && filter.select(info)) {
 				result.add(info);
 			}
 		}
 		return (SyncInfo[]) result.toArray(new SyncInfo[result.size()]);
 	}

 	/**
 	 * Returns <code>true</code> if this sync set has incoming changes.
 	 * Note that conflicts are not considered to be incoming changes.
 	 */
 	public boolean hasIncomingChanges() {
 		return countFor(SyncInfo.INCOMING, SyncInfo.DIRECTION_MASK) > 0;
 	}

 	/**
 	 * Returns <code>true</code> if this sync set has outgoing changes.
 	 * Note that conflicts are not considered to be outgoing changes.
 	 */
 	public boolean hasOutgoingChanges() {
 		return countFor(SyncInfo.OUTGOING, SyncInfo.DIRECTION_MASK) > 0;
 	}

 	/**
 	 * This method is used to obtain a lock on the set which ensures thread safety
 	 * and batches change notification. If the set is locked by another thread,
 	 * the calling thread will block until the lock
 	 * becomes available. This method uses an <code>org.eclipse.core.runtime.jobs.ILock</code>.
 	 * <p>
 	 * It is important that the lock is released after it is obtained. Calls to <code>endInput</code>
 	 * should be done in a finally block as illustrated in the following code snippet.
 	 * <pre>
 	 *   try {
 	 *       set.beginInput();
 	 *       // do stuff
 	 *   } finally {
 	 *      set.endInput(progress);
 	 *   }
 	 * </pre>
 	 * Calls to <code>beginInput</code> and <code>endInput</code> can be nested and must be matched.
 	 */
 	public void beginInput() {
 		lock.acquire();
 	}

 	/**
 	 * This method is used to release the lock on this set. The prgress monitor is needed to allow
 	 * listeners to perform long-running operations is reponse to the set change. The lock is held
 	 * while the listeners are notified so listeners must be cautious in order to avoid deadlock.
 	 */
 	public void endInput(IProgressMonitor monitor) {
 		try {
 			if (lock.getDepth() == 1) {
 				// Remain locked while firing the events so the handlers
 				// can expect the set to remain constant while they process the events
 				fireChanges(Policy.monitorFor(monitor));
 			}
 		} finally {
 			lock.release();
 		}
 	}

 	/**
 	 * Reset the changes accumulated so far by this set.
 	 * This method is not intended to be invoked or
 	 * implemented by clients.
 	 *
 	 */
 	protected void resetChanges() {
 		changes = createEmptyChangeEvent();
 	}

 	/**
 	 * Create an empty change event. Subclass may override to provided specialized event types
 	 * @return an empty change event
 	 */
 	protected SyncSetChangedEvent createEmptyChangeEvent() {
 		return new SyncSetChangedEvent(this);
 	}

 	private void fireChanges(final IProgressMonitor monitor) {
 		// Use a synchronized block to ensure that the event we send is static
 		final SyncSetChangedEvent event;
 		synchronized(this) {
 			event = getChangeEvent();
 			resetChanges();
 		}
 		// Ensure that the list of listeners is not changed while events are fired.
 		// Copy the listeners so that addition/removal is not blocked by event listeners
 		if(event.isEmpty() && ! event.isReset()) return;
 		ISyncInfoSetChangeListener[] allListeners = getListeners();
 		// Fire the events using an ISafeRunnable
 		final ITeamStatus[] newErrors = event.getErrors();
 		monitor.beginTask(null, 100 + (newErrors.length > 0 ? 50 : 0) * allListeners.length);
 		for (int i = 0; i < allListeners.length; i++) {
 			final ISyncInfoSetChangeListener listener = allListeners[i];
 			Platform.run(new ISafeRunnable() {
 				public void handleException(Throwable exception) {
 					// don't log the exception....it is already being logged in Platform#run
 				}
 				public void run() throws Exception {
 					try {
 						lockedForModification = true;
 						if (event.isReset()) {
 							listener.syncInfoSetReset(SyncInfoSet.this, Policy.subMonitorFor(monitor, 100));
 						} else {
 							listener.syncInfoChanged(event, Policy.subMonitorFor(monitor, 100));
 						}
 						if (newErrors.length > 0) {
 							listener.syncInfoSetErrors(SyncInfoSet.this, newErrors, Policy.subMonitorFor(monitor, 50));
 						}
 					} finally {
 						lockedForModification = false;
 					}
 				}
 			});
 		}
 		monitor.done();
 	}

 	/**
 	 * Return a copy of all the listeners registered with this set
 	 * @return the listeners
 	 */
 	protected ISyncInfoSetChangeListener[] getListeners() {
 		ISyncInfoSetChangeListener[] allListeners;
 		synchronized(listeners) {
 			allListeners = (ISyncInfoSetChangeListener[]) listeners.toArray(new ISyncInfoSetChangeListener[listeners.size()]);
 		}
 		return allListeners;
 	}

 	/**
 	 * Return the change event that is accumulating the changes to the set.
 	 * This can be called by sublasses to access the event.
 	 * @return Returns the changes.
 	 */
 	protected SyncSetChangedEvent getChangeEvent() {
 		return changes;
 	}

 	/**
 	 * Add the error to the set. Errors should be added to the set when the client
 	 * populating the set cannot determine the <code>SyncInfo</code> for one
 	 * or more resources due to an exception or some other problem. Listeners
 	 * will be notified that an error occurred and can react accordingly.
 	 * Only one error can be associated with a resource (which is obtained from
 	 * the <code>ITeamStatus</code>). It is up to the
 	 * client populating the set to ensure that the error associated with a
 	 * resource contains all relevent information.
 	 * The error will remain in the set until the set is reset.
 	 * @param resource the resource associated with the error or the workspace root
 	 * @param status the status that describes the error that occurred.
 	 */
 	public void addError(ITeamStatus status) {
 		try {
 			beginInput();
 			errors.put(status.getResource(), status);
 			getChangeEvent().errorOccurred(status);
 		} finally {
 			endInput(null);
 		}
 	}

 	/**
 	 * Return an array of the errors the occurred while populating this set.
 	 * The errors will remain with the set until it is reset.
 	 * @return the errors
 	 */
 	public ITeamStatus[] getErrors() {
 		return (ITeamStatus[]) errors.values().toArray(new ITeamStatus[errors.size()]);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2003 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Common Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/cpl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.team.core.synchronize;

	import java.util.*;

	import org.eclipse.core.resources.IResource;
	import org.eclipse.core.resources.IWorkspaceRunnable;
	import org.eclipse.core.runtime.*;
	import org.eclipse.core.runtime.jobs.ILock;
	import org.eclipse.team.core.ITeamStatus;
	import org.eclipse.team.core.TeamStatus;
	import org.eclipse.team.core.synchronize.FastSyncInfoFilter.SyncInfoDirectionFilter;
	import org.eclipse.team.internal.core.*;
	import org.eclipse.team.internal.core.subscribers.SyncInfoStatistics;
	import org.eclipse.team.internal.core.subscribers.SyncSetChangedEvent;

	/**
	* A dynamic collection of {@link SyncInfo} objects that provides
	* change notification to registered listeners. Batching of change notifications
	* can be accomplished using the <code>beginInput/endInput</code> methods.
	* @see SyncInfoTree
	* @see SyncInfo
	* @see ISyncInfoSetChangeListener
	* @since 3.0
	*/
	public class SyncInfoSet {
	// fields used to hold resources of interest
	// {IPath -> SyncInfo}
	private Map resources = Collections.synchronizedMap(new HashMap());

	// keep track of number of sync kinds in the set
	private SyncInfoStatistics statistics = new SyncInfoStatistics();

	// keep track of errors that occurred while trying to populate the set
	private Map errors = new HashMap();

	private boolean lockedForModification;

	/**
	* Create an empty set.
	*/
	public SyncInfoSet() {
	}

	/**
	* Create a <code>SyncInfoSet</code> containing the given <code>SyncInfo</code>
	* instances
	* @param infos the <code>SyncInfo</code> instances to be contained by this set
	*/
	public SyncInfoSet(SyncInfo[] infos) {
	this();
	// use the internal add since we can't have listeners at this point anyway
	for (int i = 0; i < infos.length; i++) {
	internalAdd(infos[i]);
	}
	}

	/**
	* Return an array of <code>SyncInfo</code> for all out-of-sync resources that are contained by the set.
	* @return an array of <code>SyncInfo</code>
	*/
	public synchronized SyncInfo[] getSyncInfos() {
	return (SyncInfo[]) resources.values().toArray(new SyncInfo[resources.size()]);
	}

	/**
	* Return all out-of-sync resources contained in this set. The default implementation
	* uses <code>getSyncInfos()</code> to determine the resources contained in the set.
	* Subclasses may override to optimize.
	* @return all out-of-sync resources contained in the set
	*/
	public IResource[] getResources() {
	SyncInfo[] infos = getSyncInfos();
	List resources = new ArrayList();
	for (int i = 0; i < infos.length; i++) {
	SyncInfo info = infos[i];
	resources.add(info.getLocal());
	}
	return (IResource[]) resources.toArray(new IResource[resources.size()]);
	}

	/**
	* Return the <code>SyncInfo</code> for the given resource or <code>null</code>
	* if the resource is not contained in the set.
	* @param resource the resource
	* @return the <code>SyncInfo</code> for the resource or <code>null</code>
	*/
	public synchronized SyncInfo getSyncInfo(IResource resource) {
	return (SyncInfo)resources.get(resource.getFullPath());
	}

	/**
	* Return the number of out-of-sync resources contained in this set.
	* @return the size of the set.
	*/
	public synchronized int size() {
	return resources.size();
	}

	/**
	* Return the number of out-of-sync resources in the given set whose sync kind
	* matches the given kind and mask (e.g. <code>(SyncInfo#getKind() & mask) == kind</code>).
	* @param kind the sync kind
	* @param mask the sync kind mask
	* @return the number of matching resources in the set.
	*/
	public long countFor(int kind, int mask) {
	return statistics.countFor(kind, mask);
	}

	/**
	* Returns <code>true</code> if there are any conflicting nodes in the set, and
	* <code>false</code> otherwise.
	*/
	public boolean hasConflicts() {
	return countFor(SyncInfo.CONFLICTING, SyncInfo.DIRECTION_MASK) > 0;
	}

	/**
	* Return whether the set is empty.
	* @return <code>true</code> if the set is empty
	*/
	public synchronized boolean isEmpty() {
	return resources.isEmpty();
	}

	/**
	* Add the <code>SyncInfo</code> to the set, replacing any previously existing one.
	* @param info the new <code>SyncInfo</code>
	*/
	protected synchronized void internalAdd(SyncInfo info) {
	Assert.isTrue(!lockedForModification);
	IResource local = info.getLocal();
	IPath path = local.getFullPath();
	SyncInfo oldSyncInfo = (SyncInfo)resources.put(path, info);
	if(oldSyncInfo == null) {
	statistics.add(info);
	} else {
	statistics.remove(oldSyncInfo);
	statistics.add(info);
	}
	}

	/**
	* Remove the resource from the set, updating all internal data structures.
	* @param resource the resource to be removed
	* @return the <code>SyncInfo</code> that was just removed
	*/
	protected synchronized SyncInfo internalRemove(IResource resource) {
	Assert.isTrue(!lockedForModification);
	IPath path = resource.getFullPath();
	SyncInfo info = (SyncInfo)resources.remove(path);
	if (info != null) {
	statistics.remove(info);
	}
	return info;
	}

	/**
	* Registers the given listener for sync info set notifications. Has
	* no effect if an identical listener is already registered.
	*
	* @param listener listener to register
	*/
	public void addSyncSetChangedListener(ISyncInfoSetChangeListener listener) {
	synchronized(listeners) {
	listeners.add(listener);
	}
	}

	/**
	* Deregisters the given listener for participant notifications. Has
	* no effect if listener is not already registered.
	*
	* @param listener listener to deregister
	*/
	public void removeSyncSetChangedListener(ISyncInfoSetChangeListener listener) {
	synchronized(listeners) {
	listeners.remove(listener);
	}
	}

	/**
	* Reset the sync set so it is empty. Listeners are notified of the change.
	*/
	public void clear() {
	try {
	beginInput();
	errors.clear();
	resources.clear();
	statistics.clear();
	getChangeEvent().reset();
	} finally {
	endInput(null);
	}
	}

	/*
	* Run the given runnable. This operation
	* will block other threads from modifying the
	* set and postpone any change notifications until after the runnable
	* has been executed. Mutable subclasses must override.
	* <p>
	* The given runnable may be run in the same thread as the caller or
	* more be run asynchronously in another thread at the discretion of the
	* subclass implementation. However, it is gaurenteed that two invocations
	* of <code>run</code> performed in the same thread will be executed in the
	* same order even if run in different threads.
	*
	* @param runnable a runnable
	* @param progress a progress monitor or <code>null</code>
	*/
	private void run(IWorkspaceRunnable runnable, IProgressMonitor monitor) {
	monitor = Policy.monitorFor(monitor);
	monitor.beginTask(null, 100);
	try {
	beginInput();
	runnable.run(Policy.subMonitorFor(monitor, 80));
	} catch (CoreException e) {
	addError(new TeamStatus(IStatus.ERROR, TeamPlugin.ID, ITeamStatus.SYNC_INFO_SET_ERROR, e.getMessage(), e, null));
	} finally {
	endInput(Policy.subMonitorFor(monitor, 20));
	}
	}

	/**
	* Connect the listener to the sync set in such a fashion that the listener will
	* be connected the the sync set using <code>addChangeListener</code>
	* and issued a reset event. This is done to provide a means of connecting to the
	* sync set and initializing a model based on the sync set without worrying about
	* missing events.
	* <p>
	* The reset event may be done in the context of this method invocation or may be
	* done in another thread at the discretion of the <code>SyncInfoSet</code>
	* implementation.
	* <p>
	* Disconnecting is done by calling <code>removeChangeListener</code>. Once disconnected,
	* a listener can reconnect to be reinitialized.
	* @param listener
	* @param monitor
	*/
	public void connect(final ISyncInfoSetChangeListener listener, IProgressMonitor monitor) {
	run(new IWorkspaceRunnable() {
	public void run(IProgressMonitor monitor) {
	try {
	monitor.beginTask(null, 100);
	addSyncSetChangedListener(listener);
	listener.syncInfoSetReset(SyncInfoSet.this, Policy.subMonitorFor(monitor, 95));
	} finally {
	monitor.done();
	}
	}
	}, monitor);
	}

	private ILock lock = Platform.getJobManager().newLock();

	private Set listeners = Collections.synchronizedSet(new HashSet());

	private SyncSetChangedEvent changes = createEmptyChangeEvent();

	/**
	* Add the given <code>SyncInfo</code> to the set. A change event will
	* be generated unless the call to this method is nested in between calls
	* to <code>beginInput()</code> and <code>endInput(IProgressMonitor)</code>
	* in which case the event for this addition and any other sync set
	* change will be fired in a batched event when <code>endInput</code>
	* is invoked.
	* Invoking this method outside of the above mentioned block will result
	* in the <code>endInput(IProgressMonitor)</code> being invoked with a null
	* progress monitor. If responsiveness is required, the client should always
	* nest sync set modifications within <code>beginInput/endInput</code>.
	* @param info
	*/
	public void add(SyncInfo info) {
	try {
	beginInput();
	boolean alreadyExists = getSyncInfo(info.getLocal()) != null;
	internalAdd(info);
	if (alreadyExists) {
	getChangeEvent().changed(info);
	} else {
	getChangeEvent().added(info);
	}
	} finally {
	endInput(null);
	}
	}

	/**
	* Add all the syncinfo from the given set to this set.
	* @param set the set whose sync info should be added to this set
	*/
	public void addAll(SyncInfoSet set) {
	try {
	beginInput();
	SyncInfo[] infos = set.getSyncInfos();
	for (int i = 0; i < infos.length; i++) {
	add(infos[i]);
	}
	} finally {
	endInput(null);
	}
	}

	/**
	* Remove the given local resource from the set.
	* @param resource the local resource to remove
	*/
	public synchronized void remove(IResource resource) {
	try {
	beginInput();
	SyncInfo info = internalRemove(resource);
	getChangeEvent().removed(resource, info);
	} finally {
	endInput(null);
	}
	}

	/**
	* Remove all the given resources from the set.
	* @param resources the resources to be removed
	*/
	public void removeAll(IResource[] resources) {
	try {
	beginInput();
	for (int i = 0; i < resources.length; i++) {
	remove(resources[i]);
	}
	} finally {
	endInput(null);
	}
	}

	/**
	* Removes all conflicting nodes from this set.
	*/
	public void removeConflictingNodes() {
	rejectNodes(new SyncInfoDirectionFilter(SyncInfo.CONFLICTING));
	}

	/**
	* Removes all outgoing nodes from this set.
	*/
	public void removeOutgoingNodes() {
	rejectNodes(new SyncInfoDirectionFilter(SyncInfo.OUTGOING));
	}

	/**
	* Removes all incoming nodes from this set.
	*/
	public void removeIncomingNodes() {
	rejectNodes(new SyncInfoDirectionFilter(SyncInfo.INCOMING));
	}

	/**
	* Indicate whether the set has nodes matching the given filter.
	* @param filter a sync info filter
	*/
	public boolean hasNodes(FastSyncInfoFilter filter) {
	SyncInfo[] infos = getSyncInfos();
	for (int i = 0; i < infos.length; i++) {
	SyncInfo info = infos[i];
	if (info != null && filter.select(info)) {
	return true;
	}
	}
	return false;
	}

	/**
	* Removes all nodes from this set that do not match the given filter
	* leaving only those that do match the filter.
	* @param filter a sync info filter
	*/
	public void selectNodes(FastSyncInfoFilter filter) {
	try {
	beginInput();
	SyncInfo[] infos = getSyncInfos();
	for (int i = 0; i < infos.length; i++) {
	SyncInfo info = infos[i];
	if (info == null \|\| !filter.select(info)) {
	remove(info.getLocal());
	}
	}
	} finally {
	endInput(null);
	}
	}

	/**
	* Removes all nodes from this set that match the given filter
	* leaving those that do not match the filter.
	* @param filter a sync info filter
	*/
	public void rejectNodes(FastSyncInfoFilter filter) {
	try {
	beginInput();
	SyncInfo[] infos = getSyncInfos();
	for (int i = 0; i < infos.length; i++) {
	SyncInfo info = infos[i];
	if (info != null && filter.select(info)) {
	remove(info.getLocal());
	}
	}
	} finally {
	endInput(null);
	}
	}

	/**
	* Return all nodes in this set that match the given filter.
	* @param filter a sync info filter
	*/
	public SyncInfo[] getNodes(FastSyncInfoFilter filter) {
	List result = new ArrayList();
	SyncInfo[] infos = getSyncInfos();
	for (int i = 0; i < infos.length; i++) {
	SyncInfo info = infos[i];
	if (info != null && filter.select(info)) {
	result.add(info);
	}
	}
	return (SyncInfo[]) result.toArray(new SyncInfo[result.size()]);
	}

	/**
	* Returns <code>true</code> if this sync set has incoming changes.
	* Note that conflicts are not considered to be incoming changes.
	*/
	public boolean hasIncomingChanges() {
	return countFor(SyncInfo.INCOMING, SyncInfo.DIRECTION_MASK) > 0;
	}

	/**
	* Returns <code>true</code> if this sync set has outgoing changes.
	* Note that conflicts are not considered to be outgoing changes.
	*/
	public boolean hasOutgoingChanges() {
	return countFor(SyncInfo.OUTGOING, SyncInfo.DIRECTION_MASK) > 0;
	}

	/**
	* This method is used to obtain a lock on the set which ensures thread safety
	* and batches change notification. If the set is locked by another thread,
	* the calling thread will block until the lock
	* becomes available. This method uses an <code>org.eclipse.core.runtime.jobs.ILock</code>.
	* <p>
	* It is important that the lock is released after it is obtained. Calls to <code>endInput</code>
	* should be done in a finally block as illustrated in the following code snippet.
	* <pre>
	* try {
	* set.beginInput();
	* // do stuff
	* } finally {
	* set.endInput(progress);
	* }
	* </pre>
	* Calls to <code>beginInput</code> and <code>endInput</code> can be nested and must be matched.
	*/
	public void beginInput() {
	lock.acquire();
	}

	/**
	* This method is used to release the lock on this set. The prgress monitor is needed to allow
	* listeners to perform long-running operations is reponse to the set change. The lock is held
	* while the listeners are notified so listeners must be cautious in order to avoid deadlock.
	*/
	public void endInput(IProgressMonitor monitor) {
	try {
	if (lock.getDepth() == 1) {
	// Remain locked while firing the events so the handlers
	// can expect the set to remain constant while they process the events
	fireChanges(Policy.monitorFor(monitor));
	}
	} finally {
	lock.release();
	}
	}

	/**
	* Reset the changes accumulated so far by this set.
	* This method is not intended to be invoked or
	* implemented by clients.
	*
	*/
	protected void resetChanges() {
	changes = createEmptyChangeEvent();
	}

	/**
	* Create an empty change event. Subclass may override to provided specialized event types
	* @return an empty change event
	*/
	protected SyncSetChangedEvent createEmptyChangeEvent() {
	return new SyncSetChangedEvent(this);
	}

	private void fireChanges(final IProgressMonitor monitor) {
	// Use a synchronized block to ensure that the event we send is static
	final SyncSetChangedEvent event;
	synchronized(this) {
	event = getChangeEvent();
	resetChanges();
	}
	// Ensure that the list of listeners is not changed while events are fired.
	// Copy the listeners so that addition/removal is not blocked by event listeners
	if(event.isEmpty() && ! event.isReset()) return;
	ISyncInfoSetChangeListener[] allListeners = getListeners();
	// Fire the events using an ISafeRunnable
	final ITeamStatus[] newErrors = event.getErrors();
	monitor.beginTask(null, 100 + (newErrors.length > 0 ? 50 : 0) * allListeners.length);
	for (int i = 0; i < allListeners.length; i++) {
	final ISyncInfoSetChangeListener listener = allListeners[i];
	Platform.run(new ISafeRunnable() {
	public void handleException(Throwable exception) {
	// don't log the exception....it is already being logged in Platform#run
	}
	public void run() throws Exception {
	try {
	lockedForModification = true;
	if (event.isReset()) {
	listener.syncInfoSetReset(SyncInfoSet.this, Policy.subMonitorFor(monitor, 100));
	} else {
	listener.syncInfoChanged(event, Policy.subMonitorFor(monitor, 100));
	}
	if (newErrors.length > 0) {
	listener.syncInfoSetErrors(SyncInfoSet.this, newErrors, Policy.subMonitorFor(monitor, 50));
	}
	} finally {
	lockedForModification = false;
	}
	}
	});
	}
	monitor.done();
	}

	/**
	* Return a copy of all the listeners registered with this set
	* @return the listeners
	*/
	protected ISyncInfoSetChangeListener[] getListeners() {
	ISyncInfoSetChangeListener[] allListeners;
	synchronized(listeners) {
	allListeners = (ISyncInfoSetChangeListener[]) listeners.toArray(new ISyncInfoSetChangeListener[listeners.size()]);
	}
	return allListeners;
	}

	/**
	* Return the change event that is accumulating the changes to the set.
	* This can be called by sublasses to access the event.
	* @return Returns the changes.
	*/
	protected SyncSetChangedEvent getChangeEvent() {
	return changes;
	}

	/**
	* Add the error to the set. Errors should be added to the set when the client
	* populating the set cannot determine the <code>SyncInfo</code> for one
	* or more resources due to an exception or some other problem. Listeners
	* will be notified that an error occurred and can react accordingly.
	* Only one error can be associated with a resource (which is obtained from
	* the <code>ITeamStatus</code>). It is up to the
	* client populating the set to ensure that the error associated with a
	* resource contains all relevent information.
	* The error will remain in the set until the set is reset.
	* @param resource the resource associated with the error or the workspace root
	* @param status the status that describes the error that occurred.
	*/
	public void addError(ITeamStatus status) {
	try {
	beginInput();
	errors.put(status.getResource(), status);
	getChangeEvent().errorOccurred(status);
	} finally {
	endInput(null);
	}
	}

	/**
	* Return an array of the errors the occurred while populating this set.
	* The errors will remain with the set until it is reset.
	* @return the errors
	*/
	public ITeamStatus[] getErrors() {
	return (ITeamStatus[]) errors.values().toArray(new ITeamStatus[errors.size()]);
	}
	}