bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/menus/MenuPersistence.java

/*******************************************************************************
 * Copyright (c) 2005, 2007 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.ui.internal.menus;

import java.util.List;

import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionDelta;
import org.eclipse.core.runtime.IExtensionRegistry;
import org.eclipse.core.runtime.IRegistryChangeEvent;
import org.eclipse.core.runtime.Platform;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.internal.registry.IWorkbenchRegistryConstants;
import org.eclipse.ui.internal.services.RegistryPersistence;

/**
 * <p>
 * A static class for accessing the registry.
 * </p>
 * <p>
 * This class is not intended for use outside of the
 * <code>org.eclipse.ui.workbench</code> plug-in.
 * </p>
 * 
 * @since 3.2
 */
final class MenuPersistence extends RegistryPersistence {

	
	private final WorkbenchMenuService menuService;
	
	/**
	 * Constructs a new instance of {@link MenuPersistence}.
	 * @param workbenchMenuService 
	 * 
	 * @param workbenchMenuService
	 *            The menu service which should be populated with the values
	 *            from the registry; must not be <code>null</code>.
	 */
	MenuPersistence(final WorkbenchMenuService workbenchMenuService) {
		if (workbenchMenuService == null) {
			throw new NullPointerException("The menu service cannot be null"); //$NON-NLS-1$
		}

		this.menuService =  workbenchMenuService;
	}

	public final void dispose() {
		super.dispose();
	}

	protected final boolean isChangeImportant(final IRegistryChangeEvent event) {
		/*
		 * TODO Menus will need to be re-read (i.e., re-verified) if any of the
		 * menu extensions change (i.e., menus), or if any of the command
		 * extensions change (i.e., action definitions).
		 */
		return false;
	}

	public boolean menusNeedUpdating(final IRegistryChangeEvent event) {
		final IExtensionDelta[] menuDeltas = event.getExtensionDeltas(
				PlatformUI.PLUGIN_ID, IWorkbenchRegistryConstants.PL_MENUS);
		if (menuDeltas.length == 0) {
			return false;
		}

		return true;
	}
	
	/**
	 * <p>
	 * Reads all of the menu elements and action sets from the registry.
	 * </p>
	 * <p>
	 * TODO Add support for modifications.
	 * </p>
	 */
	protected final void read() {
		super.read();
		
		// Read legacy 3.2 'trim' additions
		readTrimAdditions();
		
		// read the 3.3 menu additions
		readAdditions();
	}
	
	//
	// 3.3 menu extension code
	// 
	
	public void readTrimAdditions() {
		if (menuService == null)
			return;
		
		final IExtensionRegistry registry = Platform.getExtensionRegistry();
		final IConfigurationElement[] configElements = registry
				.getConfigurationElementsFor(EXTENSION_MENUS);

		// Create a cache entry for every menu addition
		for (int i = 0; i < configElements.length; i++) {
			// Only process 'group' entries
			if (!TAG_GROUP.equals(configElements[i].getName()))
				continue;
			
			String id = configElements[i].getAttribute(IWorkbenchRegistryConstants.ATT_ID);
			
			// Define the initial URI spec
			String uriSpec = "toolbar:" + id; //$NON-NLS-1$
			if (configElements[i].getChildren(TAG_LOCATION).length > 0) {
				IConfigurationElement location = configElements[i].getChildren(TAG_LOCATION)[0];
				if (location.getChildren(TAG_ORDER).length > 0) {
					IConfigurationElement order = location.getChildren(TAG_ORDER)[0];
					
					String pos = order.getAttribute(IWorkbenchRegistryConstants.ATT_POSITION);
					String relTo = order.getAttribute(IWorkbenchRegistryConstants.ATT_RELATIVE_TO);
					uriSpec += "?" + pos + "=" + relTo; //$NON-NLS-1$ //$NON-NLS-2$
					
					// HACK! We expect that the new trim group is -always- relative to
					// one of the 'default' groups; indicating which trim area they're in
					MenuLocationURI uri = new MenuLocationURI("toolbar:" + relTo); //$NON-NLS-1$
					List trimAdditions = menuService.getAdditionsForURI(uri);
					
					//
					// TODO convert the TrimAdditionCacheEntry over to use the
					//      new MenuCacheEntry and addCacheForURI(*)
					// OK, add the addition to this area
					uri = new MenuLocationURI(uriSpec);
					trimAdditions.add(new TrimAdditionCacheEntry(configElements[i], uri, menuService));
				}
				else {
					// Must be a default group; make a new entry cache
					MenuLocationURI uri = new MenuLocationURI(uriSpec);
					
					// NOTE: 'getAdditionsForURI' forces creation
					menuService.getAdditionsForURI(uri);
				}
			}
		}
	}
	
	public void readAdditions() {		
		final IExtensionRegistry registry = Platform.getExtensionRegistry();
		final IConfigurationElement[] menusExtensionPoint = registry
				.getConfigurationElementsFor(EXTENSION_MENUS);

		// Create a cache entry for every menu addition
		for (int i = 0; i < menusExtensionPoint.length; i++) {
			if (PL_MENU_CONTRIBUTION.equals(menusExtensionPoint[i].getName())) {
				// Determine the insertion location by parsing the URI
				String location = menusExtensionPoint[i]
						.getAttribute(TAG_LOCATION_URI);

				menuService.addContributionFactory(new MenuAdditionCacheEntry(menuService,
						menusExtensionPoint[i], location,
						menusExtensionPoint[i].getNamespaceIdentifier()));
			}
		}
	}
}