| /******************************************************************************* |
| * Copyright (c) 2007, 2009 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.internal.model.value; |
| |
| import org.eclipse.jpt.utility.model.event.CollectionAddEvent; |
| import org.eclipse.jpt.utility.model.event.CollectionChangeEvent; |
| import org.eclipse.jpt.utility.model.event.CollectionClearEvent; |
| import org.eclipse.jpt.utility.model.event.CollectionRemoveEvent; |
| import org.eclipse.jpt.utility.model.listener.CollectionChangeListener; |
| import org.eclipse.jpt.utility.model.value.CollectionValueModel; |
| |
| /** |
| * This abstract class provides the infrastructure needed to wrap |
| * another collection value model, "lazily" listen to it, and propagate |
| * its change notifications. Subclasses must implement the appropriate |
| * {@link CollectionValueModel}. |
| */ |
| public abstract class CollectionValueModelWrapper<E> |
| extends AbstractCollectionValueModel |
| { |
| /** The wrapped collection value model. */ |
| protected final CollectionValueModel<? extends E> collectionHolder; |
| |
| /** A listener that allows us to synch with changes to the wrapped collection holder. */ |
| protected final CollectionChangeListener collectionChangeListener; |
| |
| |
| // ********** constructors ********** |
| |
| /** |
| * Construct a collection value model with the specified wrapped |
| * collection value model. |
| */ |
| protected CollectionValueModelWrapper(CollectionValueModel<? extends E> collectionHolder) { |
| super(); |
| this.collectionHolder = collectionHolder; |
| this.collectionChangeListener = this.buildCollectionChangeListener(); |
| } |
| |
| |
| // ********** initialization ********** |
| |
| protected CollectionChangeListener buildCollectionChangeListener() { |
| return new CollectionChangeListener() { |
| public void itemsAdded(CollectionAddEvent event) { |
| CollectionValueModelWrapper.this.itemsAdded(event); |
| } |
| public void itemsRemoved(CollectionRemoveEvent event) { |
| CollectionValueModelWrapper.this.itemsRemoved(event); |
| } |
| public void collectionCleared(CollectionClearEvent event) { |
| CollectionValueModelWrapper.this.collectionCleared(event); |
| } |
| public void collectionChanged(CollectionChangeEvent event) { |
| CollectionValueModelWrapper.this.collectionChanged(event); |
| } |
| @Override |
| public String toString() { |
| return "collection change listener"; //$NON-NLS-1$ |
| } |
| }; |
| } |
| |
| |
| // ********** AbstractCollectionValueModel implementation ********** |
| |
| /** |
| * Start listening to the collection holder. |
| */ |
| @Override |
| protected void engageModel() { |
| this.collectionHolder.addCollectionChangeListener(CollectionValueModel.VALUES, this.collectionChangeListener); |
| } |
| |
| /** |
| * Stop listening to the collection holder. |
| */ |
| @Override |
| protected void disengageModel() { |
| this.collectionHolder.removeCollectionChangeListener(CollectionValueModel.VALUES, this.collectionChangeListener); |
| } |
| |
| |
| // ********** helper methods ********** |
| |
| // minimize scope of suppressed warnings |
| @SuppressWarnings("unchecked") |
| protected Iterable<E> getItems(CollectionAddEvent event) { |
| return (Iterable<E>) event.getItems(); |
| } |
| |
| // minimize scope of suppressed warnings |
| @SuppressWarnings("unchecked") |
| protected Iterable<E> getItems(CollectionRemoveEvent event) { |
| return (Iterable<E>) event.getItems(); |
| } |
| |
| |
| // ********** collection change support ********** |
| |
| /** |
| * Items were added to the wrapped collection holder; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void itemsAdded(CollectionAddEvent event); |
| |
| /** |
| * Items were removed from the wrapped collection holder; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void itemsRemoved(CollectionRemoveEvent event); |
| |
| /** |
| * The wrapped collection holder was cleared; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void collectionCleared(CollectionClearEvent event); |
| |
| /** |
| * The value of the wrapped collection holder has changed; |
| * propagate the change notification appropriately. |
| */ |
| protected abstract void collectionChanged(CollectionChangeEvent event); |
| |
| } |