IDEGeneratedElementListenerDeltaVisitor.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.client.ui.ide.generatedelementlistener;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Set;

import org.eclipse.core.resources.IResource;
import org.eclipse.core.resources.IResourceDelta;
import org.eclipse.core.resources.IResourceDeltaVisitor;
import org.eclipse.emf.common.util.URI;

/**
 * Visits a resource delta and detects the listened changed or removed resources.
 * 
 * @author <a href="mailto:alex.lagarde@obeo.fr">Alex Lagarde</a>
 */
public class IDEGeneratedElementListenerDeltaVisitor implements IResourceDeltaVisitor {
	/**
	 * All the EMF resource of the WorkspaceRepository that have changed.
	 */
	protected Collection<URI> changedResources;

	/**
	 * All the EMF resource of the WorkspaceRepository that have been removed of this repository.
	 */
	protected Collection<URI> removedResources;

	/**
	 * {@link URI}s of the listened elements.
	 */
	protected Set<URI> listenedElementsURIs;

	/**
	 * IDEGeneratedElementListenerDeltaVisitor constructor.
	 * 
	 * @param listenedElementsURIs
	 *            the list of listened element's URIs
	 */
	public IDEGeneratedElementListenerDeltaVisitor(Set<URI> listenedElementsURIs) {
		this.listenedElementsURIs = listenedElementsURIs;
		changedResources = new ArrayList<URI>();
		removedResources = new ArrayList<URI>();
	}

	/**
	 * {@inheritDoc}
	 * 
	 * @see org.eclipse.core.resources.IResourceDeltaVisitor#visit(org.eclipse.core.resources.IResourceDelta)
	 */
	public boolean visit(IResourceDelta delta) {

		if (delta.getResource().getType() != IResource.FILE) {
			return true;
		}

		if (isRelevantModification(delta)) {

			// We first calculate the repository relative path for this resource
			String uri = delta.getFullPath().toString();
			URI changedResourceURI = URI.createPlatformResourceURI(uri, false);

			if ((changedResourceURI != null) && (listenedElementsURIs.contains(changedResourceURI))) {
				switch (delta.getKind()) {
					case IResourceDelta.REMOVED:
						removedResources.add(changedResourceURI);
						break;

					case IResourceDelta.ADDED:
					case IResourceDelta.CHANGED:
						changedResources.add(changedResourceURI);
						break;

					default:
						break;
				}
			}

		}

		return true;
	}

	/**
	 * Indicates if the given delta describes a relevant modification.
	 * 
	 * @param delta
	 *            the visited delta
	 * @return true if the given delta describes a relevant modification false otherwise
	 */
	protected boolean isRelevantModification(IResourceDelta delta) {
		// First of all, we test if this delta describes an deletion, an addition or a modification
		boolean isRelevantModification = (delta.getKind() == IResourceDelta.REMOVED)
				|| (delta.getKind() == IResourceDelta.CHANGED) || delta.getKind() == IResourceDelta.ADDED;
		// The we ensure that this delta isn't a touch or a marker modification
		isRelevantModification = isRelevantModification && (delta.getFlags() != IResourceDelta.MARKERS);
		return isRelevantModification;
	}

	/**
	 * Returns the list of changed Resources's URIs.
	 * 
	 * @return the list of changed Resources 's URIs
	 */
	public Collection<URI> getChangedResources() {
		return changedResources;
	}

	/**
	 * Returns the list of removed Resources's URIs.
	 * 
	 * @return the list of removed Resources 's URIs
	 */
	public Collection<URI> getRemovedResources() {
		return removedResources;
	}
}