/*******************************************************************************
 * 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
 *******************************************************************************/

module org.eclipse.core.databinding.observable.set.ListToSetAdapter;

import java.lang.all;

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 : ObservableSet {

    private final IObservableList list;

    private IListChangeListener listener = new class() 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 this(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 !is null && listener !is null) {
            list.removeListChangeListener(listener);
            listener = null;
        }
    }

}