DiagramGlobalActionHandlerProvider.java

/******************************************************************************
 * Copyright (c) 2002, 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.gmf.runtime.diagram.ui.providers;

import java.util.Hashtable;

import org.eclipse.gmf.runtime.common.ui.services.action.global.AbstractGlobalActionHandlerProvider;
import org.eclipse.gmf.runtime.common.ui.services.action.global.IGlobalActionHandler;
import org.eclipse.gmf.runtime.common.ui.services.action.global.IGlobalActionHandlerContext;
import org.eclipse.ui.IPartListener;
import org.eclipse.ui.IWorkbenchPart;

/**
 * Concrete class that implements the <code>IGlobalActionHandlerProvider</code>.
 * 
 * @author Vishy Ramaswamy
 */
public final class DiagramGlobalActionHandlerProvider
	extends AbstractGlobalActionHandlerProvider {

	/**
	 * List that contains all the IGlobalActionHandlers mapped to the
	 * IWorkbenchParts
	 */
	private Hashtable handlerList = new Hashtable();

	/**
	 * Constructor for DiagramGlobalActionHandlerProvider.
	 */
	public DiagramGlobalActionHandlerProvider() {
		super();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.gmf.runtime.common.ui.services.action.global.IGlobalActionHandlerProvider#getGlobalActionHandler(org.eclipse.gmf.runtime.common.ui.services.action.global.IGlobalActionHandlerContext)
	 */
	public IGlobalActionHandler getGlobalActionHandler(
			final IGlobalActionHandlerContext context) {
		/* create the handler */
		if (!getHandlerList().containsKey(context.getActivePart())) {
			getHandlerList().put(context.getActivePart(),
				new DiagramGlobalActionHandler());
			/*
			 * register as a part listener so that the cache can be cleared when
			 * the part is disposed
			 */
			context.getActivePart().getSite().getPage().addPartListener(
				new IPartListener() {

					private IWorkbenchPart localPart = context.getActivePart();

					/**
					 * @see org.eclipse.ui.IPartListener#partActivated(IWorkbenchPart)
					 */
					public void partActivated(IWorkbenchPart part) {
						// NULL implementation
					}

					/**
					 * @see org.eclipse.ui.IPartListener#partBroughtToTop(IWorkbenchPart)
					 */
					public void partBroughtToTop(IWorkbenchPart part) {
						// NULL implementation
					}

					/**
					 * @see org.eclipse.ui.IPartListener#partClosed(IWorkbenchPart)
					 */
					public void partClosed(IWorkbenchPart part) {
						/* remove the cache associated with the part */
						if (part != null && part == localPart
							&& getHandlerList().containsKey(part)) {
							getHandlerList().remove(part);
							localPart.getSite().getPage().removePartListener(
								this);
							localPart = null;
						}
					}

					/**
					 * @see org.eclipse.ui.IPartListener#partDeactivated(IWorkbenchPart)
					 */
					public void partDeactivated(IWorkbenchPart part) {
						// NULL implementation
					}

					/**
					 * @see org.eclipse.ui.IPartListener#partOpened(IWorkbenchPart)
					 */
					public void partOpened(IWorkbenchPart part) {
						// NULL implementation
					}
				});
		}
		return (DiagramGlobalActionHandler) getHandlerList().get(
			context.getActivePart());
	}

	/**
	 * Returns the handlerList.
	 * 
	 * @return Hashtable
	 */
	private Hashtable getHandlerList() {
		return handlerList;
	}
}