| /******************************************************************************* |
| * Copyright (c) 2009, 2010 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 java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.Collection; |
| |
| import org.eclipse.jpt.utility.internal.IdentityHashBag; |
| 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.event.PropertyChangeEvent; |
| import org.eclipse.jpt.utility.model.listener.PropertyChangeListener; |
| import org.eclipse.jpt.utility.model.value.CollectionValueModel; |
| import org.eclipse.jpt.utility.model.value.PropertyValueModel; |
| |
| /** |
| * A <code>CompositePropertyValueModel</code> adapts a |
| * {@link CollectionValueModel} holding other {@link PropertyValueModel}s |
| * to a single {@link PropertyValueModel}. |
| * <p> |
| * Subclasses must implement:<ul> |
| * <li>{@link #buildValue()}<p> |
| * to return the current property value, as derived from the |
| * component values |
| * </ul> |
| * <strong>NB:</strong> The wrapped collection must not contain any duplicates |
| * or this class will throw an exception. |
| */ |
| public abstract class CompositePropertyValueModel<V> |
| extends CollectionPropertyValueModelAdapter<V> |
| { |
| /** |
| * Cache the component property value models so we can stop listening to |
| * them when they are removed from the collection value model. |
| */ |
| protected final IdentityHashBag<PropertyValueModel<?>> componentPVMs = |
| new IdentityHashBag<PropertyValueModel<?>>(); |
| |
| /** |
| * Listen to every property value model in the collection value model. |
| * If one changes, we need to re-calculate our value. |
| */ |
| protected final PropertyChangeListener propertyChangeListener; |
| |
| |
| // ********** constructors ********** |
| |
| /** |
| * Construct a property value model that is a composite of the specified |
| * property value models. |
| */ |
| public CompositePropertyValueModel(PropertyValueModel<?>... collection) { |
| this(Arrays.asList(collection)); |
| } |
| |
| /** |
| * Construct a property value model that is a composite of the specified |
| * property value models. |
| */ |
| public <E extends PropertyValueModel<?>> CompositePropertyValueModel(Collection<E> collection) { |
| this(new StaticCollectionValueModel<E>(collection)); |
| } |
| |
| /** |
| * Construct a property value model that is a composite of the specified |
| * property value models. |
| */ |
| public CompositePropertyValueModel(CollectionValueModel<? extends PropertyValueModel<?>> collectionModel) { |
| super(collectionModel); |
| this.propertyChangeListener = this.buildPropertyChangeListener(); |
| } |
| |
| |
| // ********** initialization ********** |
| |
| protected PropertyChangeListener buildPropertyChangeListener() { |
| return new PropertyChangeListener() { |
| public void propertyChanged(PropertyChangeEvent event) { |
| CompositePropertyValueModel.this.propertyChanged(event); |
| } |
| @Override |
| public String toString() { |
| return "property change listener"; //$NON-NLS-1$ |
| } |
| }; |
| } |
| |
| |
| // ********** behavior ********** |
| |
| /** |
| * Subclasses can override this method if the event can be used to improve |
| * the performance of building a new value (e.g. some property changes may |
| * not necessitate the re-calculation of the value). |
| */ |
| protected void propertyChanged(@SuppressWarnings("unused") PropertyChangeEvent event) { |
| this.propertyChanged(); |
| } |
| |
| |
| // ********** CollectionPropertyValueModelAdapter overrides ********** |
| |
| @Override |
| protected void engageModel_() { |
| super.engageModel_(); |
| this.addComponentPVMs(this.getCollectionModel()); |
| } |
| |
| protected <E extends PropertyValueModel<?>> void addComponentPVMs(Iterable<E> pvms) { |
| for (PropertyValueModel<?> each : pvms) { |
| this.componentPVMs.add(each); |
| each.addPropertyChangeListener(VALUE, this.propertyChangeListener); |
| } |
| } |
| |
| @Override |
| protected void disengageModel_() { |
| this.removeComponentPVMs(this.getCollectionModel()); |
| super.disengageModel_(); |
| } |
| |
| protected <E extends PropertyValueModel<?>> void removeComponentPVMs(Iterable<E> pvms) { |
| for (PropertyValueModel<?> each : pvms) { |
| each.removePropertyChangeListener(VALUE, this.propertyChangeListener); |
| this.componentPVMs.remove(each); |
| } |
| } |
| |
| @Override |
| protected void itemsAdded(CollectionAddEvent event) { |
| this.addComponentPVMs(this.getItems(event)); |
| super.itemsAdded(event); |
| } |
| |
| @Override |
| protected void itemsRemoved(CollectionRemoveEvent event) { |
| this.removeComponentPVMs(this.getItems(event)); |
| super.itemsRemoved(event); |
| } |
| |
| @Override |
| protected void collectionCleared(CollectionClearEvent event) { |
| this.removeAllComponentPVMs(); |
| super.collectionCleared(event); |
| } |
| |
| protected void removeAllComponentPVMs() { |
| // copy the list so we don't eat our own tail |
| ArrayList<PropertyValueModel<?>> copy = new ArrayList<PropertyValueModel<?>>(this.componentPVMs); |
| this.removeComponentPVMs(copy); |
| } |
| |
| @Override |
| protected void collectionChanged(CollectionChangeEvent event) { |
| this.removeAllComponentPVMs(); |
| this.addComponentPVMs(this.getCollectionModel()); |
| super.collectionChanged(event); |
| } |
| |
| |
| // ********** convenience methods ********** |
| |
| /** |
| * Our constructor accepts only a {@link CollectionValueModel}{@code<? extends }{@link PropertyValueModel}{@code<?>>}. |
| */ |
| // minimize scope of suppressed warnings |
| @SuppressWarnings("unchecked") |
| protected CollectionValueModel<? extends PropertyValueModel<?>> getCollectionModel() { |
| return (CollectionValueModel<? extends PropertyValueModel<?>>) this.collectionModel; |
| } |
| |
| /** |
| * Our constructor accepts only a {@link CollectionValueModel}{@code<? extends }{@link PropertyValueModel}{@code<?>>}. |
| */ |
| @SuppressWarnings("unchecked") |
| protected Iterable<? extends PropertyValueModel<?>> getItems(CollectionAddEvent event) { |
| return (Iterable<? extends PropertyValueModel<?>>) event.getItems(); |
| } |
| |
| /** |
| * Our constructor accepts only a {@link CollectionValueModel}{@code<? extends }{@link PropertyValueModel}{@code<?>>}. |
| */ |
| @SuppressWarnings("unchecked") |
| protected Iterable<? extends PropertyValueModel<?>> getItems(CollectionRemoveEvent event) { |
| return (Iterable<? extends PropertyValueModel<?>>) event.getItems(); |
| } |
| |
| } |