/*******************************************************************************
* Copyright (c) 2006, 2007 IBM Corporation and others.
* 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.core.databinding.observable.set;
import java.util.HashSet;
import java.util.Set;
import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.list.IListChangeListener;
import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.list.ListChangeEvent;
import org.eclipse.core.databinding.observable.list.ListDiffEntry;
/**
* Observable set backed by an observable list. The wrapped list must not
* contain duplicate elements.
*
* <p>
* This class is thread safe. All state accessing methods must be invoked from
* the {@link Realm#isCurrent() current realm}. Methods for adding and removing
* listeners may be invoked from any thread.
* </p>
*
* @since 1.0
*
*/
public class ListToSetAdapter extends ObservableSet {
private final IObservableList list;
private IListChangeListener listener = new IListChangeListener() {
public void handleListChange(ListChangeEvent event) {
Set added = new HashSet();
Set removed = new HashSet();
ListDiffEntry[] differences = event.diff.getDifferences();
for (int i = 0; i < differences.length; i++) {
ListDiffEntry entry = differences[i];
Object element = entry.getElement();
if (entry.isAddition()) {
if (wrappedSet.add(element)) {
if (!removed.remove(element))
added.add(element);
}
} else {
if (wrappedSet.remove(element)) {
removed.add(element);
added.remove(element);
}
}
}
fireSetChange(Diffs.createSetDiff(added, removed));
}
};
/**
* @param list
*/
public ListToSetAdapter(IObservableList list) {
super(list.getRealm(), new HashSet(), list.getElementType());
this.list = list;
wrappedSet.addAll(list);
this.list.addListChangeListener(listener);
}
public synchronized void dispose() {
super.dispose();
if (list != null && listener != null) {
list.removeListChangeListener(listener);
listener = null;
}
}
}