| /******************************************************************************* |
| * Copyright (c) 2006 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.navigator.dnd; |
| |
| import java.lang.ref.WeakReference; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.Set; |
| |
| import org.eclipse.ui.navigator.INavigatorContentService; |
| |
| /** |
| * Caches instances of {@link INavigatorContentService} to facilitate the |
| * handling of drop operations in other viewers. |
| * |
| * @since 3.2 |
| * |
| */ |
| public class NavigatorContentServiceTransfer { |
| |
| private static final NavigatorContentServiceTransfer instance = new NavigatorContentServiceTransfer(); |
| |
| /** |
| * |
| * @return The singleton instance of the transfer service. |
| */ |
| public static NavigatorContentServiceTransfer getInstance() { |
| return instance; |
| } |
| |
| private final Set registeredContentServices = new HashSet(); |
| |
| /** |
| * |
| * @param aContentService The Content Service to register. |
| */ |
| public synchronized void registerContentService(INavigatorContentService aContentService) { |
| if(findService(aContentService.getViewerId()) == null) { |
| registeredContentServices.add(new WeakReference(aContentService)); |
| } |
| } |
| |
| /** |
| * |
| * @param aContentService The Content Service to unregister. |
| */ |
| public synchronized void unregisterContentService(INavigatorContentService aContentService) { |
| |
| for (Iterator iter = registeredContentServices.iterator(); iter.hasNext();) { |
| WeakReference ref = (WeakReference) iter.next(); |
| if(ref.get() == null) { |
| iter.remove(); |
| } else { |
| if(ref.get() == aContentService) { |
| iter.remove(); |
| return; |
| } |
| } |
| } |
| } |
| |
| /** |
| * |
| * @param aViewerId A viewer id that should have previously been registered with the service. |
| * @return The registered content service for the given viewer id. |
| */ |
| public synchronized INavigatorContentService findService(String aViewerId) { |
| if(aViewerId == null || aViewerId.length() == 0) { |
| return null; |
| } |
| INavigatorContentService contentService; |
| for (Iterator iter = registeredContentServices.iterator(); iter.hasNext();) { |
| WeakReference ref = (WeakReference) iter.next(); |
| if(ref.get() == null) { |
| iter.remove(); |
| } else { |
| contentService = (INavigatorContentService)ref.get(); |
| if(aViewerId.equals(contentService.getViewerId())) { |
| return contentService; |
| } |
| } |
| } |
| return null; |
| } |
| |
| |
| } |