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/*******************************************************************************
* 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.internal.model.value;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import org.eclipse.jpt.utility.internal.iterators.EmptyIterator;
import org.eclipse.jpt.utility.model.Model;
import org.eclipse.jpt.utility.model.event.TreeChangeEvent;
import org.eclipse.jpt.utility.model.listener.ChangeListener;
import org.eclipse.jpt.utility.model.listener.TreeChangeListener;
import org.eclipse.jpt.utility.model.value.PropertyValueModel;
import org.eclipse.jpt.utility.model.value.TreeValueModel;
/**
* This extension of PropertyAdapter provides TreeChange support.
* This allows us to convert a set of one or more trees into
* a single tree, NODES.
*
* The typical subclass will override the following methods:
* #nodes_()
* 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
* #nodes() is overridden and its behavior changed
* #nodes()
* override this method only if returning an empty iterator when the
* subject is null is unacceptable
*/
public abstract class TreeAspectAdapter<S extends Model, E>
extends AspectAdapter<S>
implements TreeValueModel<E>
{
/**
* The name of the subject's trees that we use for the value.
*/
protected final String[] treeNames;
protected static final String[] EMPTY_TREE_NAMES = new String[0];
/** A listener that listens to the subject's tree aspect. */
protected final TreeChangeListener treeChangeListener;
// ********** constructors **********
/**
* Construct a TreeAspectAdapter for the specified subject
* and tree.
*/
protected TreeAspectAdapter(String treeName, S subject) {
this(new String[] {treeName}, subject);
}
/**
* Construct a TreeAspectAdapter for the specified subject
* and trees.
*/
protected TreeAspectAdapter(String[] treeNames, S subject) {
this(new StaticPropertyValueModel<S>(subject), treeNames);
}
/**
* Construct a TreeAspectAdapter for the specified subject holder
* and trees.
*/
protected TreeAspectAdapter(PropertyValueModel<? extends S> subjectHolder, String... treeNames) {
super(subjectHolder);
this.treeNames = treeNames;
this.treeChangeListener = this.buildTreeChangeListener();
}
/**
* Construct a TreeAspectAdapter for the specified subject holder
* and trees.
*/
protected TreeAspectAdapter(PropertyValueModel<? extends S> subjectHolder, Collection<String> treeNames) {
this(subjectHolder, treeNames.toArray(new String[treeNames.size()]));
}
/**
* Construct a TreeAspectAdapter for an "unchanging" tree in
* the specified subject. This is useful for a tree aspect that does not
* change for a particular subject; but the subject will change, resulting in
* a new tree.
*/
protected TreeAspectAdapter(PropertyValueModel<? extends S> subjectHolder) {
this(subjectHolder, EMPTY_TREE_NAMES);
}
// ********** initialization **********
/**
* The subject's tree aspect has changed, notify the listeners.
*/
protected TreeChangeListener buildTreeChangeListener() {
// transform the subject's tree change events into VALUE tree change events
return new TreeChangeListener() {
public void nodeAdded(TreeChangeEvent event) {
TreeAspectAdapter.this.nodeAdded(event);
}
public void nodeRemoved(TreeChangeEvent event) {
TreeAspectAdapter.this.nodeRemoved(event);
}
public void treeCleared(TreeChangeEvent event) {
TreeAspectAdapter.this.treeCleared(event);
}
public void treeChanged(TreeChangeEvent event) {
TreeAspectAdapter.this.treeChanged(event);
}
@Override
public String toString() {
return "tree change listener: " + Arrays.asList(TreeAspectAdapter.this.treeNames);
}
};
}
// ********** 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 that the subject is not null.
* @see #nodes()
*/
protected Iterator<E> nodes_() {
throw new UnsupportedOperationException();
}
// ********** AspectAdapter implementation **********
@Override
protected Object getValue() {
return this.nodes();
}
@Override
protected Class<? extends ChangeListener> getListenerClass() {
return TreeChangeListener.class;
}
@Override
protected String getListenerAspectName() {
return NODES;
}
@Override
protected boolean hasListeners() {
return this.hasAnyTreeChangeListeners(NODES);
}
@Override
protected void fireAspectChange(Object oldValue, Object newValue) {
this.fireTreeChanged(NODES);
}
@Override
protected void engageSubject_() {
for (String treeName : this.treeNames) {
((Model) this.subject).addTreeChangeListener(treeName, this.treeChangeListener);
}
}
@Override
protected void disengageSubject_() {
for (String treeName : this.treeNames) {
((Model) this.subject).removeTreeChangeListener(treeName, this.treeChangeListener);
}
}
@Override
public void toString(StringBuilder sb) {
for (int i = 0; i < this.treeNames.length; i++) {
if (i != 0) {
sb.append(", ");
}
sb.append(this.treeNames[i]);
}
}
// ********** behavior **********
protected void nodeAdded(TreeChangeEvent event) {
this.fireNodeAdded(NODES, event.getPath());
}
protected void nodeRemoved(TreeChangeEvent event) {
this.fireNodeRemoved(NODES, event.getPath());
}
protected void treeCleared(TreeChangeEvent event) {
this.fireTreeCleared(NODES);
}
protected void treeChanged(TreeChangeEvent event) {
this.fireTreeChanged(NODES, event.getPath());
}
}
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