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/*******************************************************************************
* Copyright (c) 2007, 2010 Oracle. 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:
* Oracle - initial API and implementation
******************************************************************************/
package org.eclipse.jpt.utility.internal.model.value;
import java.util.Iterator;
import org.eclipse.jpt.utility.internal.iterators.EmptyIterator;
import org.eclipse.jpt.utility.internal.model.AbstractModel;
import org.eclipse.jpt.utility.model.value.CollectionValueModel;
/**
* A read-only collection value model for when you
* don't need to support a collection. In particular, this
* is useful for the leaf nodes of a tree that never have
* children.
* <p>
* We don't use a singleton because we hold on to listeners.
*/
public final class NullCollectionValueModel<E>
extends AbstractModel
implements CollectionValueModel<E>
{
private static final long serialVersionUID = 1L;
/**
* Default constructor.
*/
public NullCollectionValueModel() {
super();
}
// ********** CollectionValueModel implementation **********
public int size() {
return 0;
}
public Iterator<E> iterator() {
return EmptyIterator.instance();
}
// ********** Object overrides **********
@Override
public String toString() {
return this.getClass().getSimpleName();
}
}
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