| /******************************************************************************* |
| * 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.TreeChangeListener; |
| import org.eclipse.jpt.common.utility.model.value.PropertyValueModel; |
| import org.eclipse.jpt.common.utility.model.value.TreeValueModel; |
| |
| /** |
| * This {@link AspectAdapter} provides basic tree change support. |
| * This converts an "aspect" (as defined by subclasses) into |
| * a single {@link #NODES} tree. |
| * <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 #nodes_()}<p> |
| * at the very minimum, override this method to return an iterator |
| * on the subject's tree aspect; it does not need to be overridden if |
| * {@link #nodes()} is overridden and its behavior changed |
| * <li>{@link #nodes()}<p> |
| * override this method only if returning an empty iterator when the |
| * subject is null is unacceptable |
| * </ul> |
| * To notify listeners, subclasses can call {@link #treeChanged()} |
| * whenever the aspect has changed. |
| */ |
| public abstract class AspectTreeValueModelAdapter<S, E> |
| extends AspectAdapter<S> |
| implements TreeValueModel<E> |
| { |
| |
| // ********** constructors ********** |
| |
| /** |
| * Construct a tree value model adapter for an aspect of the |
| * specified subject. |
| */ |
| protected AspectTreeValueModelAdapter(PropertyValueModel<? extends S> subjectHolder) { |
| super(subjectHolder); |
| } |
| |
| |
| // ********** TreeValueModel implementation ********** |
| |
| /** |
| * Return the nodes of the subject's tree aspect. |
| */ |
| public Iterator<E> nodes() { |
| return (this.subject == null) ? EmptyIterator.<E>instance() : this.nodes_(); |
| } |
| |
| /** |
| * Return the nodes of the subject's tree aspect. |
| * At this point we can be sure the subject is not null. |
| * @see #nodes() |
| */ |
| protected Iterator<E> nodes_() { |
| throw new RuntimeException("This method was not overridden."); //$NON-NLS-1$ |
| } |
| |
| |
| // ********** AspectAdapter implementation ********** |
| |
| @Override |
| protected Object getValue() { |
| return this.buildValueCollection(); |
| } |
| |
| @Override |
| protected Class<? extends EventListener> getListenerClass() { |
| return TreeChangeListener.class; |
| } |
| |
| @Override |
| protected String getListenerAspectName() { |
| return NODES; |
| } |
| |
| @Override |
| protected boolean hasListeners() { |
| return this.hasAnyTreeChangeListeners(NODES); |
| } |
| |
| @Override |
| protected void fireAspectChanged(Object oldValue, Object newValue) { |
| @SuppressWarnings("unchecked") Collection<E> newNodes = (Collection<E>) newValue; |
| this.fireTreeChanged(NODES, newNodes); |
| } |
| |
| protected void treeChanged() { |
| this.fireTreeChanged(NODES, this.buildValueCollection()); |
| } |
| |
| protected Collection<E> buildValueCollection() { |
| return CollectionTools.collection(this.nodes()); |
| } |
| |
| @Override |
| public void toString(StringBuilder sb) { |
| sb.append(this.buildValueCollection()); |
| } |
| |
| } |