/*******************************************************************************
 * 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.jface.databinding.viewers.ListeningLabelProvider;

import java.lang.all;

import java.util.Iterator;

import org.eclipse.core.databinding.observable.set.IObservableSet;
import org.eclipse.core.databinding.observable.set.ISetChangeListener;
import org.eclipse.core.databinding.observable.set.SetChangeEvent;
import org.eclipse.jface.internal.databinding.provisional.viewers.ViewerLabelProvider;

/**
 * @since 1.1
 * 
 */
public abstract class ListeningLabelProvider : ViewerLabelProvider {

    private ISetChangeListener listener = new class() ISetChangeListener {
        public void handleSetChange(SetChangeEvent event) {
            for (Iterator it = event.diff.getAdditions().iterator(); it.hasNext();) {
                addListenerTo(it.next());
            }
            for (Iterator it = event.diff.getRemovals().iterator(); it.hasNext();) {
                removeListenerFrom(it.next());
            }
        }
    };

    private IObservableSet items;

    /**
     * @param itemsThatNeedLabels
     */
    public this(IObservableSet itemsThatNeedLabels) {
        this.items = itemsThatNeedLabels;
        items.addSetChangeListener(listener);
        for (Iterator it = items.iterator(); it.hasNext();) {
            addListenerTo(it.next());
        }
    }

    /**
     * @param next
     */
    protected abstract void removeListenerFrom(Object next);

    /**
     * @param next
     */
    protected abstract void addListenerTo(Object next);

    public void dispose() {
        for (Iterator iter = items.iterator(); iter.hasNext();) {
            removeListenerFrom(iter.next());
        }
        items.removeSetChangeListener(listener);
        super.dispose();
    }
}