ObservableList.java

/*******************************************************************************
 * Copyright (c) 2004, 2013 Steve Flasby
 * All rights reserved.
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * <ul>
 *     <li>Redistributions of source code must retain the above copyright notice,
 *         this list of conditions and the following disclaimer.</li>
 *     <li>Redistributions in binary form must reproduce the above copyright notice,
 *         this list of conditions and the following disclaimer in the documentation
 *         and/or other materials provided with the distribution.</li>
 * </ul>
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ******************************************************************************/
package org.flasby.util;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;


public class ObservableList<T> extends AbstractObservable implements List<T>, Observer {
	private final List<T> list;
	private final List<T> unmodifiableList;

	public static <S> ObservableList<S> wrap(List<S> list) {
		return new ObservableList<S>(list);
	}
	public ObservableList() {
		this(new ArrayList<T>());
	}
	private ObservableList(List<T> list) {
		this.list = list;
		this.unmodifiableList = Collections.unmodifiableList(list);
	}
	
	public void notifyChange(T object) {
		notifyObservers(object);
	}
	public void notifyChanges() {
		notifyObservers();
	}
	
	@Override
	public boolean add(T object) {
		boolean result = list.add(object);
		if(result) {
			notifyObservers(object);
			doAddObserver( object );
		}
		return result;
	}
	@Override
	public boolean remove(Object object) {
		boolean result = list.remove(object);
		if(result) {
			notifyObservers(object);
			doRemoveObserver(object);
		}
		return result;
	}
	public List<T> get() {
		return unmodifiableList;
	}
	
	@Override
	public boolean contains(Object o) {
		return list.contains(o);
	}
	@Override
	public boolean containsAll(Collection<?> c) {
		return list.containsAll(c);
	}
	@Override
	public int size() {
		return list.size();
	}
	@Override
	public void add(int index, T object) {
		list.add(index, object);
		notifyObservers(object);
		doAddObserver( object );
	}
	/**
	 * adds a new element and notofies observers if this changed the array.
	 */
	@Override
	public boolean addAll(Collection<? extends T> c) {
		boolean result = list.addAll(c);
		if(result) {
			notifyObservers();
			for(T object: c) {
				doAddObserver( object );
			}
		}
		return result;
	}
	
	@Override
	public boolean addAll(int index, Collection<? extends T> c) {
		boolean result = list.addAll(index, c);
		if(result) { 
			notifyObservers();
			for(T object: c) {
				doAddObserver( object );
			}
		}
		return result;
	}
	@Override
	public void clear() {
		for(T object: list) {
			doRemoveObserver(object);
		}
		list.clear();
		notifyObservers();
	}
	@Override
	public boolean equals(Object o) {
		return list.equals(o);
	}
	@Override
	public T get(int index) {
		return list.get(index);
	}
	@Override
	public int hashCode() {
		return list.hashCode();
	}
	@Override
	public int indexOf(Object o) {
		return list.indexOf(o);
	}
	@Override
	public boolean isEmpty() {
		return list.isEmpty();
	}
	@Override
	public Iterator<T> iterator() {
		return list.iterator();
	}
	@Override
	public int lastIndexOf(Object o) {
		return list.lastIndexOf(o);
	}
	@Override
	public ListIterator<T> listIterator() {
		return list.listIterator();
	}
	@Override
	public ListIterator<T> listIterator(int index) {
		return list.listIterator(index);
	}
	@Override
	public T remove(int index) {
		T o = list.remove(index);
		if(o != null) {
			notifyObservers(o);
			doAddObserver( o );
		}
		return o;
}
	@Override
	public boolean removeAll(Collection<?> c) {
		boolean result = list.removeAll(c);
		if(result) {
			notifyObservers();
			for(Object object: c) {
				doRemoveObserver(object);
			}
		}
		return result;
	}
	@Override
	public boolean retainAll(Collection<?> c) {
		for(T object: list) {
			if(!c.contains(object)) {
				doAddObserver( object );
			}
		}
		boolean result = list.retainAll(c);
		if(result) notifyObservers();
		return result;
	}
	@Override
	public T set(int index, T element) {
		T o =  list.set(index, element);
		if(element instanceof Observable) {
			((Observable)element).addObserver(this);
		}
		if(o != null) {
			notifyObservers();
			doAddObserver( o );
		}
		return o;
	}
	@Override
	public List<T> subList(int fromIndex, int toIndex) {
		return list.subList(fromIndex, toIndex);
	}
	@Override
	public Object[] toArray() {
		return list.toArray();
	}
	@Override
	public <S> S[] toArray(S[] a) {
		return list.toArray(a);
	}
	@Override
	public void update(Observable o, Object arg) {
		notifyObservers(o);
	}
	@Override
	public void update(Observable o) {
		notifyObservers(o);
	}

	private void doAddObserver( Object object ) {
		if(object instanceof Observable) {
			((Observable)object).addObserver(this);
		}
	}
	private void doRemoveObserver( Object object ) {
		if(object instanceof Observable) {
			((Observable)object).removeObserver(this);
		}
	}
}