WorkspaceTypeListener.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.notification;

import com.google.common.collect.Sets;

import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;

import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.ENamedElement;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.mylyn.docs.intent.collab.handlers.notification.Notificator;
import org.eclipse.mylyn.docs.intent.collab.handlers.notification.RepositoryChangeNotification;
import org.eclipse.mylyn.docs.intent.collab.handlers.notification.RepositoryChangeNotificationFactoryHolder;

/**
 * Listens for any change that occur on an instance of the given types, an notify the associated
 * TypeNotificator.
 * 
 * @author <a href="mailto:alex.lagarde@obeo.fr">Alex Lagarde</a>
 */
public class WorkspaceTypeListener {

	/**
	 * The type notificator to notify if changes are detected.
	 */
	private final Notificator typeNotificator;

	/**
	 * List of the types to listen.
	 */
	private final Set<EStructuralFeature> listenedTypes;

	/**
	 * WorkspaceTypeListener constructor.
	 * 
	 * @param typeNotificator
	 *            The type notificator to notify if changes are detected
	 * @param typesToListen
	 *            List of the types to listen
	 */
	public WorkspaceTypeListener(Notificator typeNotificator, Set<EStructuralFeature> typesToListen) {
		this.typeNotificator = typeNotificator;
		this.listenedTypes = new LinkedHashSet<EStructuralFeature>();
		this.listenedTypes.addAll(typesToListen);
	}

	/**
	 * This method is called by the Workspace Session any time a resource located on the repository changes ;
	 * must notify the notificator if the resource contained one of the listened types.
	 * 
	 * @param resource
	 *            the resource that has changed
	 */
	public void notifyResourceChanged(Resource resource) {
		boolean changesDetected = false;

		// We determine if any of the roots contained in the resource is a listened type
		Iterator<EObject> contentIterator = Sets.newLinkedHashSet(resource.getContents()).iterator();
		while (contentIterator.hasNext() && !changesDetected) {
			EObject nextRoot = contentIterator.next();

			Iterator<EStructuralFeature> rootFeaturesIterator = nextRoot.eClass().getEAllStructuralFeatures()
					.iterator();
			while (rootFeaturesIterator.hasNext() && !changesDetected) {
				EStructuralFeature next = rootFeaturesIterator.next();
				changesDetected = isListenedTypeModification(next);
			}
		}

		// If this type Listener must notify its associated notificator
		if (changesDetected) {
			RepositoryChangeNotification newNotification = RepositoryChangeNotificationFactoryHolder
					.getChangeNotificationFactory().createRepositoryChangeNotification(resource);
			if (newNotification != null) {
				this.typeNotificator.notifyHandlers(newNotification);
			}
		}
	}

	/**
	 * Returns true if the given feature matches any listened types of this typeListener.
	 * 
	 * @param feature
	 *            the feature to test.
	 * @return true if the given feature matches any listened types of this typeListener, false otherwise.
	 */
	private boolean isListenedTypeModification(EStructuralFeature feature) {
		boolean isListenedType = false;
		for (Iterator<EStructuralFeature> iterator = listenedTypes.iterator(); iterator.hasNext()
				&& !isListenedType;) {
			ENamedElement listenedtype = iterator.next();
			if (listenedtype instanceof EStructuralFeature) {
				isListenedType = listenedtype.equals(feature);
			}
			if (listenedtype instanceof EClass) {

				isListenedType = ((EClass)listenedtype).getEAllStructuralFeatures().contains(feature);
			}

		}
		return isListenedType;
	}

}