plugins/org.eclipse.mylyn.docs.intent.collab.ide/src/org/eclipse/mylyn/docs/intent/collab/ide/adapters/WorkspaceAdapter.java

/*******************************************************************************
 * Copyright (c) 2010, 2011 Obeo.
 * 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:
 *     Obeo - initial API and implementation
 *******************************************************************************/
package org.eclipse.mylyn.docs.intent.collab.ide.adapters;

import com.google.common.base.Predicate;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.eclipse.emf.common.command.CommandStack;
import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.resource.ResourceSet;
import org.eclipse.emf.ecore.resource.URIConverter;
import org.eclipse.emf.ecore.resource.impl.ResourceSetImpl;
import org.eclipse.emf.ecore.util.EcoreUtil;
import org.eclipse.emf.ecore.xmi.XMLResource;
import org.eclipse.emf.ecore.xmi.impl.XMLParserPoolImpl;
import org.eclipse.emf.transaction.RecordingCommand;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.emf.transaction.impl.InternalTransactionalEditingDomain;
import org.eclipse.mylyn.docs.intent.collab.handlers.adapters.IntentCommand;
import org.eclipse.mylyn.docs.intent.collab.handlers.adapters.ReadOnlyException;
import org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter;
import org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryStructurer;
import org.eclipse.mylyn.docs.intent.collab.handlers.adapters.SaveException;
import org.eclipse.mylyn.docs.intent.collab.handlers.notification.Notificator;
import org.eclipse.mylyn.docs.intent.collab.ide.notification.WorkspaceTypeListener;
import org.eclipse.mylyn.docs.intent.collab.ide.repository.WorkspaceRepository;
import org.eclipse.mylyn.docs.intent.collab.ide.repository.WorkspaceSession;
import org.eclipse.mylyn.docs.intent.collab.repository.Repository;
import org.eclipse.mylyn.docs.intent.collab.repository.RepositoryConnectionException;

/**
 * Adapter that allows the RepositoryObjectHandler to work with an Eclipse Workspace.
 * 
 * @author <a href="mailto:alex.lagarde@obeo.fr">Alex Lagarde</a>
 * @author <a href="mailto:william.piers@obeo.fr">William Piers</a>
 */
public class WorkspaceAdapter implements RepositoryAdapter {

	/**
	 * Represents the time to wait before asking the Workspace Session if it's locked.
	 */
	private static final long TIME_TO_WAIT_BEFORE_CHECKING_SESSIONDELTA = 5;

	/**
	 * Time to wait for the editing domain availability (if exceded, then we will not execute the command and
	 * throw an exception).
	 */
	private static final long TIMEOUT = 15000;

	/**
	 * The save options that have to be used for saving resources of this repository.
	 */
	private static Map<String, Object> saveOptions;

	/**
	 * The load options that have to be used for loading this repository.
	 */
	private static Map<String, Object> loadOptions;

	/**
	 * The Workspace repository associated to this adapter.
	 */
	private WorkspaceRepository repository;

	/**
	 * Indicates if the current opened context is ReadOnly (false if Read/Write).
	 */
	private boolean isReadOnlyContext;

	/**
	 * Mapping between notificator and listeners.
	 */
	private Map<Notificator, Set<WorkspaceTypeListener>> notificatorToListener;

	/**
	 * The {@link RepositoryStructurer} used to structured the IntentDocument.
	 */
	private RepositoryStructurer documentStructurer;

	/**
	 * Indicates if this adapter should send or not warning to the WorkspaceSession before saving a resource
	 * (default value : true).
	 */
	private boolean sendSessionWarningBeforeSaving;

	/**
	 * A list of path that should not cause warning sending to the WorkspaceSession before saving a resource
	 * conform to the given path.
	 * <p>
	 * For example, if this list contain '/FOLDER/SUBFOLDER1/', any resource located in this folder or
	 * sub-folders should be ignored. It can also contains path relative to a single resource, like
	 * '/FOLDER/SUBFOLDER1/MySingleResource'.
	 * </p>
	 */
	private List<String> resourcesToIgnorePaths;

	/**
	 * A {@link Predicate} that returns true if the considered resource must not be unloaded when undoing
	 * changes, false otherwise.
	 */
	private Predicate<Resource> unloadableResourcePredicate = new Predicate<Resource>() {

		public boolean apply(Resource input) {
			// Default implementation considers that all resources should be unloaded when undoing changes
			return false;
		}
	};

	/**
	 * WorkspaceAdapterconstructor.
	 * 
	 * @param repository
	 *            the Workspace repository associated to this adapter
	 */
	public WorkspaceAdapter(WorkspaceRepository repository) {
		this.repository = repository;
		this.isReadOnlyContext = false;
		this.notificatorToListener = new HashMap<Notificator, Set<WorkspaceTypeListener>>();
		this.resourcesToIgnorePaths = new ArrayList<String>();
	}

	/**
	 * Returns the save options that have to be used for saving resources.
	 * 
	 * @return the save options that have to be used for saving resources
	 */
	public static Map<String, Object> getSaveOptions() {
		if (saveOptions == null) {
			saveOptions = new HashMap<String, Object>();
			// We do not format the document when saving (less human-readable but faster to save and to load)
			saveOptions.put(XMLResource.OPTION_FORMATTED, false);
		}
		return saveOptions;
	}

	/**
	 * Returns the load options that have to be used for loading resources.
	 * 
	 * @return the load options that have to be used for loading resources
	 */
	public static Map<String, Object> getLoadOptions() {
		if (loadOptions == null) {
			loadOptions = new HashMap<String, Object>();
			// We want the resource to be saved only if changes have been detected.
			// In order to make the system as scalable as possible,
			// We use a fileBuffer instead of a memory buffer
			loadOptions.put(XMLResource.OPTION_DEFER_IDREF_RESOLUTION, true);
			// Parser Pool for tweaking performances
			loadOptions.put(XMLResource.OPTION_USE_PARSER_POOL, new XMLParserPoolImpl());
		}
		return loadOptions;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#openSaveContext()
	 */
	public Object openSaveContext() {
		// Nothing to do here except setting the isReadOnluContext value to false
		isReadOnlyContext = false;
		return null;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#openReadOnlyContext()
	 */
	public Object openReadOnlyContext() {
		// Nothing to do here except setting the isReadOnluContext value to true
		isReadOnlyContext = true;
		return null;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#save()
	 */
	public void save() throws ReadOnlyException, SaveException {
		if (isReadOnlyContext) {
			throw new ReadOnlyException(
					"Cannot save with a read-only context. The context should have been started with the 'openSaveContext' method.");
		}

		// Step 1: we use the documentStructurer to structure the resource set
		if (documentStructurer != null) {
			documentStructurer.structure(WorkspaceAdapter.this);
		}
		final Collection<Resource> resources = Lists.newArrayList(this.repository.getResourceSet()
				.getResources());
		SaveException saveException = null;
		try {
			for (Resource resource : resources) {
				if (resource != null && isRepositoryResource(resource.getURI())) {
					try {
						if (!removeDanglingElements(resource) && hasDifferentSerialization(resource)) {
							try {
								// We make sure the session isn't still reacting to previous saves
								while (((WorkspaceSession)this.repository.getOrCreateSession())
										.isProcessingDelta()) {
									Thread.sleep(TIME_TO_WAIT_BEFORE_CHECKING_SESSIONDELTA);
								}

								// Step 2: we send a warning to the WorkspaceSession if necessary
								treatSessionWarning(resource);

								// Step 3: save the resource

								if (resource.getContents().isEmpty()) {
									// if the resource is empty, we delete it
									resource.delete(getSaveOptions());
								} else {
									resource.save(getSaveOptions());
								}
							} catch (IOException e) {
								removeDanglingElements(resource);
							} catch (RepositoryConnectionException e) {
								saveException = new SaveException(e.getMessage());
							}
						}
					} catch (RepositoryConnectionException e) {
						saveException = new SaveException(e.getMessage());
					} catch (IOException e) {
						saveException = new SaveException(e.getMessage());
					} catch (InterruptedException e) {
						throw new SaveException(e.getMessage());
					} catch (UnsupportedOperationException e) {
						// Silently removing resource : it is not saveable
						this.repository.getResourceSet().getResources().remove(resource);
					} catch (IllegalStateException e) {
						e.printStackTrace();
					}

				} else {
					// If repository generated elements reference external content, then we should not save
					// them: the save method purpose is to commit the modification made on the repository
					this.repository.getResourceSet().getResources().remove(resource);
				}
			}
		} catch (ConcurrentModificationException cme) {
			// If there were a concurrent modification, we simply retry
			// FIXME : can we make a better choice ? The causes of this exception don't seem obvious
			save();
		}
		if (saveException != null) {
			throw saveException;
		}

	}

	/**
	 * Returns true if the resource will get a different serialization than the one on the disk.
	 * 
	 * @param resourcetoSave
	 *            the resource to serialize
	 * @return true if the resource will get a different serialization than the one on the disk.
	 * @throws IOException
	 *             on error while saving.
	 */
	public boolean hasDifferentSerialization(final Resource resourcetoSave) throws IOException {
		// CHECKSTYLE:OFF : code coming from
		// ResourceImpl.saveOnlyIfChangedWithFileBuffer
		resourcetoSave.eSetDeliver(false);
		final File temporaryFile = File.createTempFile("ResourceSaveHelper", null);
		boolean equal = true;
		try {
			final URI temporaryFileURI = URI.createFileURI(temporaryFile.getPath());

			final URIConverter uriConverter = resourcetoSave.getResourceSet() == null ? new ResourceSetImpl()
					.getURIConverter() : resourcetoSave.getResourceSet().getURIConverter();
			final OutputStream temporaryFileOutputStream = uriConverter.createOutputStream(temporaryFileURI);
			try {
				resourcetoSave.save(temporaryFileOutputStream, getSaveOptions());
			} finally {
				temporaryFileOutputStream.close();
			}

			InputStream oldContents = null;
			try {
				oldContents = uriConverter.createInputStream(resourcetoSave.getURI());
			} catch (final IOException exception) {
				equal = false;
			}
			final byte[] newContentBuffer = new byte[4000];
			if (oldContents != null) {
				try {
					final InputStream newContents = uriConverter.createInputStream(temporaryFileURI);
					try {
						final byte[] oldContentBuffer = new byte[4000];
						LOOP: for (int oldLength = oldContents.read(oldContentBuffer), newLength = newContents
								.read(newContentBuffer); (equal = oldLength == newLength) && oldLength > 0; oldLength = oldContents
								.read(oldContentBuffer), newLength = newContents.read(newContentBuffer)) {
							for (int i = 0; i < oldLength; ++i) {
								if (oldContentBuffer[i] != newContentBuffer[i]) {
									equal = false;
									break LOOP;
								}
							}
						}
					} finally {
						newContents.close();
					}
				} finally {
					oldContents.close();
				}
			}
		} finally {
			temporaryFile.delete();
			resourcetoSave.eSetDeliver(true);
		}
		// CHECKSTYLE:ON

		// return !equal || resourcetoSave.getURI().toString().contains("StatusIndex");
		return !equal;
	}

	/**
	 * Determine if a warning should be sent to the WorkspaceSession before saving the given resource and send
	 * this warning.
	 * <p>
	 * If a warning is sent, the WorkspaceSession will ignore the next modification made on the given
	 * resource.
	 * </p>
	 * 
	 * @param resource
	 *            the resource being saved
	 * @throws RepositoryConnectionException
	 *             if a connection to the repository cannot be made
	 */
	private void treatSessionWarning(Resource resource) throws RepositoryConnectionException {
		// If this adapter must warn the session about any saved resource
		if (sendSessionWarningBeforeSaving) {
			// We warn the session
			((WorkspaceSession)this.repository.getOrCreateSession()).addSavedResource(resource);
		} else {
			// If the given resource must be ignored (i.e is include in any of the
			// resourcesToIgnorePaths)
			if (isInResourcesToIgnorePath(resource)) {
				// We warn the session
				((WorkspaceSession)this.repository.getOrCreateSession()).addSavedResource(resource);
			}
		}
	}

	/**
	 * Indicates if the given resource is conform to any declared resourceToIgnore path.
	 * 
	 * @param resource
	 *            the resource to determine if it's conform to any declared resourceToIgnore path
	 * @return true if the given resource is conform to any declared resourceToIgnore path , false otherwise
	 */
	public boolean isInResourcesToIgnorePath(Resource resource) {
		boolean isInResourceToIgnorePath = false;
		Iterator<String> iterator = this.resourcesToIgnorePaths.iterator();
		while (iterator.hasNext() && !isInResourceToIgnorePath) {
			String resourceToIgnorePath = iterator.next();
			isInResourceToIgnorePath = this.repository.isIncludedInPath(resourceToIgnorePath, resource);
		}
		return isInResourceToIgnorePath;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#undo()
	 */
	public void undo() throws ReadOnlyException {
		// TODO accurate undo strategy
		CommandStack commandStack = repository.getEditingDomain().getCommandStack();
		if (commandStack != null) {
			commandStack.undo();
		} else {
			// TODO ?
		}
	}

	/**
	 * Sets a predicate that will be used to determine which resource must not be unloaded when undoing
	 * changes.
	 * 
	 * @param unloadableResourcePredicate
	 *            a {@link Predicate} that returns true if the considered resource must not be unloaded when
	 *            undoing changes, false otherwise
	 */
	public void setUnloadableResourcePredicate(Predicate<Resource> unloadableResourcePredicate) {
		this.unloadableResourcePredicate = unloadableResourcePredicate;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#closeContext()
	 */
	public void closeContext() {
		isReadOnlyContext = false;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#attachSessionListenerForTypes(org.eclipse.mylyn.docs.intent.collab.handlers.notification.Notificator,
	 *      java.util.Set)
	 */
	public void attachSessionListenerForTypes(Notificator typeNotificator,
			Set<EStructuralFeature> listenedTypes) {
		try {

			WorkspaceTypeListener typeListener = new WorkspaceTypeListener(typeNotificator, listenedTypes);
			if (this.notificatorToListener.get(typeNotificator) == null) {
				this.notificatorToListener.put(typeNotificator, new LinkedHashSet<WorkspaceTypeListener>());
			}
			this.notificatorToListener.get(typeNotificator).add(typeListener);
			((WorkspaceSession)this.repository.getOrCreateSession()).addListener(typeListener);
		} catch (RepositoryConnectionException e) {
			// TODO handle properly such a repository connection exception
		}

	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#detachSessionListenerForTypes(org.eclipse.mylyn.docs.intent.collab.handlers.notification.Notificator)
	 */
	public void detachSessionListenerForTypes(Notificator typeNotificator) {
		try {
			for (WorkspaceTypeListener listenerToRemove : this.notificatorToListener.get(typeNotificator)) {
				((WorkspaceSession)this.repository.getOrCreateSession()).removeListener(listenerToRemove);
			}

			this.notificatorToListener.remove(typeNotificator);
		} catch (RepositoryConnectionException e) {
			// TODO handle properly such a repository connection exception
		}

	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#allowChangeSubscriptionPolicy()
	 */
	public void allowChangeSubscriptionPolicy() {
		// Nothing to do here
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getContext()
	 */
	public Object getContext() {
		// No context to return as no context was created
		return null;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getResource(java.lang.String)
	 */
	public Resource getResource(String repositoryRelativePath) {
		return getResource(repositoryRelativePath, true);
	}

	/**
	 * Returns the resource located at the given path.
	 * 
	 * @param repositoryRelativePath
	 *            path of the searched resource (from the root of the repository)
	 * @param loadResourceOnDemand
	 *            indicates if the resource should be loaded on demand or not
	 * @return the resource located at the given path
	 */
	public Resource getResource(String repositoryRelativePath, boolean loadResourceOnDemand) {
		// We calculate the Repository URI corresponding to the given path
		URI uri = this.repository.getURIMatchingPath(repositoryRelativePath);
		final Resource resource = this.repository.getResourceSet().getResource(uri, loadResourceOnDemand);
		return resource;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getOrCreateResource(java.lang.String)
	 */
	public Resource getOrCreateResource(String path) throws ReadOnlyException {
		if (isReadOnlyContext) {
			throw new ReadOnlyException(
					"Cannot create a resource with a read-only context. The context should have been started with the 'openSaveContext' method.");
		}

		// We calculate the Repository URI corresponding to the given path
		URI uri = this.repository.getURIMatchingPath(path);

		// We first try to get the resource
		Resource returnedResource = this.repository.getResourceSet().getResource(uri, false);
		if (returnedResource == null) {
			// If it doesn't exist, we create it
			returnedResource = this.repository.getResourceSet().createResource(uri);
		} else {
			if (!returnedResource.isLoaded()) {
				try {
					returnedResource.load(getLoadOptions());
				} catch (IOException e) {
					returnedResource = null;
				}
			}
		}
		return returnedResource;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getElementWithID(java.lang.Object)
	 */
	public EObject getElementWithID(Object uri) {
		if (uri instanceof URI) {
			EObject eObject = this.repository.getResourceSet().getEObject((URI)uri, true);
			return eObject;
		}
		return null;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getIDFromElement(org.eclipse.emf.ecore.EObject)
	 */
	public Object getIDFromElement(EObject element) {
		URI uri = null;
		if (element != null) {
			uri = EcoreUtil.getURI(element);

			// if the URI starts with "#", it means that the resource is no longer part of the resource set.
			// we return null to indicate the the given element is now invalid
			if (uri.toString().startsWith("#")) {
				return null;
			}
		}
		return uri;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#attachRepositoryStructurer(org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryStructurer)
	 */
	public void attachRepositoryStructurer(RepositoryStructurer structurer) {
		if (!(structurer instanceof RepositoryStructurer)) {
			throw new IllegalArgumentException("Cannot attach " + structurer.getClass().getName()
					+ " to this adapter : should be " + RepositoryStructurer.class.getName());
		}
		documentStructurer = structurer;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#setSendSessionWarningBeforeSaving(boolean)
	 */
	public void setSendSessionWarningBeforeSaving(boolean notifySessionBeforeSaving) {
		this.sendSessionWarningBeforeSaving = notifySessionBeforeSaving;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#setSendSessionWarningBeforeSaving(java.util.Collection)
	 */
	public void setSendSessionWarningBeforeSaving(Collection<String> resourcesToIgnorePathList) {
		this.sendSessionWarningBeforeSaving = false;
		this.resourcesToIgnorePaths.clear();
		this.resourcesToIgnorePaths.addAll(resourcesToIgnorePathList);
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#reload(org.eclipse.emf.ecore.EObject)
	 */
	public EObject reload(EObject elementToReload) {
		EObject resolve = elementToReload;
		if (elementToReload.eIsProxy()) {
			resolve = EcoreUtil.resolve(elementToReload, this.repository.getResourceSet());
		}
		return resolve;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#execute(org.eclipse.mylyn.docs.intent.collab.handlers.adapters.IntentCommand)
	 */
	public void execute(final IntentCommand command) {
		// Step 1: create a recording command encapsulating the Intent command
		final TransactionalEditingDomain editingDomain = repository.getEditingDomain();
		final RecordingCommand recordingCommand = new RecordingCommand(editingDomain) {
			@Override
			protected void doExecute() {
				command.execute();
			}
		};

		// Step 2: make sure a command is not already running
		final CommandStack commandStack = editingDomain.getCommandStack();
		// Check that the repository has not been disposed
		if (commandStack != null) {
			// Check that change recorder is not already recording
			long timeout = System.currentTimeMillis();
			try {
				while (((InternalTransactionalEditingDomain)editingDomain).getChangeRecorder().isRecording()
						&& System.currentTimeMillis() < timeout + TIMEOUT) {
					try {
						Thread.sleep(TIME_TO_WAIT_BEFORE_CHECKING_SESSIONDELTA);
					} catch (InterruptedException e) {
						// Command will be executed
					}
				}

				// Step 3: execute command
				commandStack.execute(recordingCommand);
			} catch (NullPointerException e) {
				// can happen when TED is disposed
			}
		}
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getResourcePath(org.eclipse.emf.common.util.URI)
	 */
	public String getResourcePath(URI resourceURI) {
		if (isRepositoryResource(resourceURI)) {
			String resourcePath = resourceURI.toString();
			resourcePath = resourcePath.replace("platform:/resource", "").replace(
					this.repository.getWorkspaceConfig().getRepositoryAbsolutePath(), "");
			if (this.repository.shouldHaveWorkspaceResourceExtension(resourcePath)) {
				resourcePath = resourcePath.replace("." + resourceURI.fileExtension(), "");
			}
			return resourcePath;
		}
		return null;
	}

	/**
	 * Indicates if the given URI describe a resource contained in the repository.
	 * 
	 * @param resourceURI
	 *            the resource URI
	 * @return true if the given URI describe a resource contained in the repository, false otherwise
	 */
	private boolean isRepositoryResource(URI resourceURI) {
		return resourceURI.toString().contains(
				this.repository.getWorkspaceConfig().getRepositoryAbsolutePath());
	}

	/**
	 * Removes the dangling references contained in the given resource and saves the resource (without
	 * notifying other clients).
	 * 
	 * @param resource
	 *            the resource to clean
	 * @return true if the given resource contained dangling references (and hence was cleaned and saved),
	 *         false otherwise
	 * @throws SaveException
	 *             if resource cannot be save
	 * @throws RepositoryConnectionException
	 *             if repository cannot be accessed
	 */
	private boolean removeDanglingElements(Resource resource) throws SaveException,
			RepositoryConnectionException {

		// Step 1: detect dangling references
		Collection<EObject> objectsToRemove = Sets.newLinkedHashSet();
		Iterator<EObject> iterator = resource.getContents().iterator();
		while (iterator.hasNext()) {
			EObject root = iterator.next();
			if (root.eContainer() != null && root.eContainer().eResource() == null) {
				objectsToRemove.add(root);
			}
		}

		try {
			if (!objectsToRemove.isEmpty()) {
				// Step 2: save or delete the resource if empty
				treatSessionWarning(resource);
				if (resource.getContents().size() <= objectsToRemove.size()) {
					resource.delete(getSaveOptions());
				} else {
					for (EObject objectToRemove : objectsToRemove) {
						EcoreUtil.remove(objectToRemove);
					}
					for (EObject nonDanglingElement : resource.getContents()) {
						new RemoveDanglingReferences(this.repository.getEditingDomain(), nonDanglingElement)
								.execute();
					}
					resource.save(getSaveOptions());
				}
				return true;
			} else {
				for (EObject nonDanglingElement : resource.getContents()) {
					new RemoveDanglingReferences(this.repository.getEditingDomain(), nonDanglingElement)
							.execute();
				}
			}
		} catch (IOException ioE) {
			throw new SaveException(ioE.getMessage());
		}
		return false;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getRepository()
	 */
	public Repository getRepository() {
		return this.repository;
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.mylyn.docs.intent.collab.handlers.adapters.RepositoryAdapter#getResourceSet()
	 */
	public ResourceSet getResourceSet() {
		return new ResourceSetImpl();
	}
}