| /******************************************************************************* |
| * Copyright (c) 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.common.utility.internal.model.value; |
| |
| import java.util.Collection; |
| import java.util.EventListener; |
| import java.util.Iterator; |
| |
| import org.eclipse.jpt.common.utility.internal.CollectionTools; |
| import org.eclipse.jpt.common.utility.internal.iterators.EmptyIterator; |
| import org.eclipse.jpt.common.utility.model.listener.CollectionChangeListener; |
| import org.eclipse.jpt.common.utility.model.value.CollectionValueModel; |
| import org.eclipse.jpt.common.utility.model.value.PropertyValueModel; |
| |
| /** |
| * This {@link AspectAdapter} provides basic collection change support. |
| * This converts an "aspect" (as defined by subclasses) into |
| * a single {@link #VALUES} collection. |
| * <p> |
| * The typical subclass will override the following methods:<ul> |
| * <li>{@link #engageSubject_()}<p> |
| * implement this method to add the appropriate listener to the subject |
| * <li>{@link #disengageSubject_()}<p> |
| * implement this method to remove the appropriate listener from the subject |
| * <li>{@link #getIterable()}<p> |
| * at the very minimum, override this method to return an iterable containing the |
| * subject's collection aspect; it does not need to be overridden if either |
| * {@link #iterator_()} or {@link #iterator()} is overridden and its behavior changed |
| * <li>{@link #size_()}<p> |
| * override this method to improve performance; it does not need to be overridden if |
| * {@link #size()} is overridden and its behavior changed |
| * <li>{@link #iterator_()}<p> |
| * override this method to return an iterator on the |
| * subject's collection aspect if it is not possible to implement {@link #getIterable()}; |
| * it does not need to be overridden if |
| * {@link #iterator()} is overridden and its behavior changed |
| * <li>{@link #iterator()}<p> |
| * override this method only if returning an empty iterator when the |
| * subject is null is unacceptable |
| * <li>{@link #size()}<p> |
| * override this method only if returning a zero when the |
| * subject is null is unacceptable |
| * </ul> |
| * To notify listeners, subclasses can call {@link #collectionChanged()} |
| * whenever the aspect has changed. |
| */ |
| public abstract class AspectCollectionValueModelAdapter<S, E> |
| extends AspectAdapter<S> |
| implements CollectionValueModel<E> |
| { |
| |
| // ********** constructors ********** |
| |
| /** |
| * Construct a collection value model adapter for an aspect of the |
| * specified subject. |
| */ |
| protected AspectCollectionValueModelAdapter(PropertyValueModel<? extends S> subjectHolder) { |
| super(subjectHolder); |
| } |
| |
| |
| // ********** CollectionValueModel implementation ********** |
| |
| /** |
| * Return the elements of the subject's collection aspect. |
| */ |
| public Iterator<E> iterator() { |
| return (this.subject == null) ? EmptyIterator.<E>instance() : this.iterator_(); |
| } |
| |
| /** |
| * Return the elements of the subject's collection aspect. |
| * At this point we can be sure the subject is not null. |
| * @see #iterator() |
| */ |
| protected Iterator<E> iterator_() { |
| return this.getIterable().iterator(); |
| } |
| |
| /** |
| * Return the elements of the subject's collection aspect. |
| * At this point we can be sure the subject is not null. |
| * @see #iterator_() |
| */ |
| protected Iterable<E> getIterable() { |
| throw new RuntimeException("This method was not overridden."); //$NON-NLS-1$ |
| } |
| |
| /** |
| * Return the size of the subject's collection aspect. |
| */ |
| public int size() { |
| return (this.subject == null) ? 0 : this.size_(); |
| } |
| |
| /** |
| * Return the size of the subject's collection aspect. |
| * At this point we can be sure the subject is not null. |
| * @see #size() |
| */ |
| protected int size_() { |
| return CollectionTools.size(this.iterator()); |
| } |
| |
| |
| // ********** AspectAdapter implementation ********** |
| |
| @Override |
| protected Object getValue() { |
| return this.buildValueCollection(); |
| } |
| |
| @Override |
| protected Class<? extends EventListener> getListenerClass() { |
| return CollectionChangeListener.class; |
| } |
| |
| @Override |
| protected String getListenerAspectName() { |
| return VALUES; |
| } |
| |
| @Override |
| protected boolean hasListeners() { |
| return this.hasAnyCollectionChangeListeners(VALUES); |
| } |
| |
| @Override |
| protected void fireAspectChanged(Object oldValue, Object newValue) { |
| @SuppressWarnings("unchecked") Collection<E> newCollection = (Collection<E>) newValue; |
| this.fireCollectionChanged(VALUES, newCollection); |
| } |
| |
| protected void collectionChanged() { |
| this.fireCollectionChanged(VALUES, this.buildValueCollection()); |
| } |
| |
| protected Collection<E> buildValueCollection() { |
| return CollectionTools.collection(this.iterator()); |
| } |
| |
| @Override |
| public void toString(StringBuilder sb) { |
| sb.append(this.buildValueCollection()); |
| } |
| |
| } |