| /******************************************************************************* |
| * Copyright (c) 2007, 2008 Oracle. 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: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.utility.model.event; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Iterator; |
| |
| import org.eclipse.jpt.utility.model.Model; |
| |
| /** |
| * A "collection change" event gets delivered whenever a model changes a "bound" |
| * or "constrained" collection. A CollectionChangeEvent is sent as an |
| * argument to the CollectionChangeListener. |
| * |
| * Normally a CollectionChangeEvent is accompanied by the collection name and |
| * the items that were added to or removed from the changed collection. |
| * |
| * Design options: |
| * - create a collection to wrap a single added or removed item |
| * (this is the option we implemented below and in collaborating code) |
| * since there is no way to optimize downstream code for |
| * single items, we take another performance hit by building |
| * a collection each time (@see Collections#singleton(Object)) |
| * and forcing downstream code to use an iterator every time |
| * |
| * - fire a separate event for each item added or removed |
| * eliminates any potential for optimizations to downstream code |
| * |
| * - add protocol to support both single items and collections |
| * adds conditional logic to downstream code |
| * |
| * Provisional API: This class is part of an interim API that is still |
| * under development and expected to change significantly before reaching |
| * stability. It is available at this early stage to solicit feedback from |
| * pioneering adopters on the understanding that any code that uses this API |
| * will almost certainly be broken (repeatedly) as the API evolves. |
| */ |
| public class CollectionChangeEvent extends ChangeEvent { |
| |
| /** Name of the collection that changed. */ |
| private final String collectionName; |
| |
| /** The items that were added to or removed from the collection. May be empty, if not known. */ |
| private final Collection<?> items; |
| |
| private static final long serialVersionUID = 1L; |
| |
| |
| // ********** constructors ********** |
| |
| /** |
| * Construct a new collection change event. |
| * |
| * @param source The object on which the event initially occurred. |
| * @param collectionName The programmatic name of the collection that was changed. |
| * @param items The items that were added to or removed from the collection. |
| */ |
| public CollectionChangeEvent(Model source, String collectionName, Collection<?> items) { |
| super(source); |
| if ((collectionName == null) || (items == null)) { |
| throw new NullPointerException(); |
| } |
| this.collectionName = collectionName; |
| this.items = Collections.unmodifiableCollection(items); |
| } |
| |
| /** |
| * Construct a new collection change event. |
| * |
| * @param source The object on which the event initially occurred. |
| * @param collectionName The programmatic name of the collection that was changed. |
| */ |
| public CollectionChangeEvent(Model source, String collectionName) { |
| this(source, collectionName, Collections.emptySet()); |
| } |
| |
| |
| // ********** standard state ********** |
| |
| /** |
| * Return the programmatic name of the collection that was changed. |
| */ |
| public String getCollectionName() { |
| return this.collectionName; |
| } |
| |
| @Override |
| public String getAspectName() { |
| return this.collectionName; |
| } |
| |
| /** |
| * Return an iterator on the items that were added to or |
| * removed from the collection. |
| * May be empty if inappropriate or unknown. |
| */ |
| public Iterator<?> items() { |
| return this.items.iterator(); |
| } |
| |
| /** |
| * Return the number of items that were added to or |
| * removed from the collection. |
| * May be 0 if inappropriate or unknown. |
| */ |
| public int itemsSize() { |
| return this.items.size(); |
| } |
| |
| |
| // ********** cloning ********** |
| |
| /** |
| * Return a copy of the event with the specified source |
| * replacing the current source. |
| */ |
| @Override |
| public CollectionChangeEvent cloneWithSource(Model newSource) { |
| return new CollectionChangeEvent(newSource, this.collectionName, this.items); |
| } |
| |
| /** |
| * Return a copy of the event with the specified source and collection name |
| * replacing the current source and collection name. |
| */ |
| public CollectionChangeEvent cloneWithSource(Model newSource, String newCollectionName) { |
| return new CollectionChangeEvent(newSource, newCollectionName, this.items); |
| } |
| |
| } |