bundles/org.eclipse.core.databinding.observable/src/org/eclipse/core/databinding/observable/set/AbstractObservableSet.java

/*******************************************************************************
 * Copyright (c) 2006, 2009 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
 *     Matthew Hall - bug 208332, 194734
 *******************************************************************************/

package org.eclipse.core.databinding.observable.set;

import java.util.Collection;
import java.util.Iterator;
import java.util.Set;

import org.eclipse.core.databinding.observable.AbstractObservable;
import org.eclipse.core.databinding.observable.ListenerList;
import org.eclipse.core.databinding.observable.ObservableTracker;
import org.eclipse.core.databinding.observable.Realm;

/**
 * 
 * Abstract implementation of {@link IObservableSet}.
 * 
 * <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>
 * 
 * @param <E>
 * 
 * @since 1.0
 */
public abstract class AbstractObservableSet<E> extends AbstractObservable
		implements IObservableSet<E> {

	private boolean stale = false;

	protected ListenerList<ISetChangeListener<E>> setChangeListenerList = null;

	protected AbstractObservableSet() {
		this(Realm.getDefault());
	}

	protected void firstListenerAdded() {
		super.firstListenerAdded();
	}

	protected void lastListenerRemoved() {
		super.lastListenerRemoved();
	}

	protected AbstractObservableSet(Realm realm) {
		super(realm);
	}

	public synchronized void addSetChangeListener(ISetChangeListener<E> listener) {
		addListener(getSetChangeListenerList(), listener);
	}

	public synchronized void removeSetChangeListener(
			ISetChangeListener<E> listener) {
		if (setChangeListenerList != null) {
			removeListener(setChangeListenerList, listener);
		}
	}

	private ListenerList<ISetChangeListener<E>> getSetChangeListenerList() {
		if (setChangeListenerList == null) {
			setChangeListenerList = new ListenerList<ISetChangeListener<E>>();
		}
		return setChangeListenerList;
	}

	protected abstract Set<E> getWrappedSet();

	protected void fireSetChange(SetDiff<E> diff) {
		// fire general change event first
		super.fireChange();

		if (setChangeListenerList != null) {
			setChangeListenerList.fireEvent(new SetChangeEvent<E>(this, diff));
		}
	}

	public boolean contains(Object o) {
		getterCalled();
		return getWrappedSet().contains(o);
	}

	public boolean containsAll(Collection<?> c) {
		getterCalled();
		return getWrappedSet().containsAll(c);
	}

	public boolean equals(Object o) {
		getterCalled();
		return getWrappedSet().equals(o);
	}

	public int hashCode() {
		getterCalled();
		return getWrappedSet().hashCode();
	}

	public boolean isEmpty() {
		getterCalled();
		return getWrappedSet().isEmpty();
	}

	public Iterator<E> iterator() {
		getterCalled();
		final Iterator<E> wrappedIterator = getWrappedSet().iterator();
		return new Iterator<E>() {

			public void remove() {
				throw new UnsupportedOperationException();
			}

			public boolean hasNext() {
				ObservableTracker.getterCalled(AbstractObservableSet.this);
				return wrappedIterator.hasNext();
			}

			public E next() {
				ObservableTracker.getterCalled(AbstractObservableSet.this);
				return wrappedIterator.next();
			}
		};
	}

	public int size() {
		getterCalled();
		return getWrappedSet().size();
	}

	public Object[] toArray() {
		getterCalled();
		return getWrappedSet().toArray();
	}

	public <T> T[] toArray(T[] a) {
		getterCalled();
		return getWrappedSet().toArray(a);
	}

	public String toString() {
		getterCalled();
		return getWrappedSet().toString();
	}

	protected void getterCalled() {
		ObservableTracker.getterCalled(this);
	}

	public boolean add(E o) {
		throw new UnsupportedOperationException();
	}

	public boolean addAll(Collection<? extends E> c) {
		throw new UnsupportedOperationException();
	}

	public boolean remove(Object o) {
		throw new UnsupportedOperationException();
	}

	public boolean removeAll(Collection<?> c) {
		throw new UnsupportedOperationException();
	}

	public boolean retainAll(Collection<?> c) {
		throw new UnsupportedOperationException();
	}

	public void clear() {
		throw new UnsupportedOperationException();
	}

	/**
	 * @return Returns the stale state.
	 */
	public boolean isStale() {
		getterCalled();
		return stale;
	}

	/**
	 * @param stale
	 *            The stale state to set. This will fire a stale event if the
	 *            given boolean is true and this observable set was not already
	 *            stale.
	 */
	public void setStale(boolean stale) {
		checkRealm();
		boolean wasStale = this.stale;
		this.stale = stale;
		if (!wasStale && stale) {
			fireStale();
		}
	}

	protected void fireChange() {
		throw new RuntimeException(
				"fireChange should not be called, use fireSetChange() instead"); //$NON-NLS-1$
	}

	/**
	 * This is a default implementation that should ideally be overridden to use
	 * a properly typed Class field. This implementation checks to see if the
	 * element type is of type Class and, if it is, it assumes it is the class
	 * of the elements and makes an unchecked cast.
	 * <P>
	 * This method should always be overridden to provide an implementation that
	 * never returns null.
	 * 
	 * @return the class of the elements, if possible, or null if this is not
	 *         possible
	 * @since 1.5
	 */
	public Class<E> getElementClass() {
		Object elementType = getElementType();
		if (elementType instanceof Class) {
			return (Class<E>) elementType;
		}
		return null;
	}
}