| /******************************************************************************* |
| * Copyright (c) 2005, 2007 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.iterators; |
| |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| import org.eclipse.jpt.utility.internal.StringTools; |
| |
| /** |
| * A <code>SingleElementIterator</code> holds a single element |
| * and returns it with the first call to {@link next()}, at |
| * which point it will return <code>false</code> to any subsequent |
| * call to {@link #hasNext()}. |
| * <p> |
| * A <code>SingleElementIterator</code> is equivalent to the |
| * {@link Iterator} returned by: |
| * {@link java.util.Collections#singleton(element)}<code>.iterator()</code> |
| * |
| * @param <E> the type of elements returned by the iterator |
| */ |
| public class SingleElementIterator<E> |
| implements Iterator<E> |
| { |
| private final E element; |
| private boolean done; |
| |
| |
| /** |
| * Construct an iterator that returns only the specified element. |
| */ |
| public SingleElementIterator(E element) { |
| super(); |
| this.element = element; |
| this.done = false; |
| } |
| |
| public boolean hasNext() { |
| return ! this.done; |
| } |
| |
| public E next() { |
| if (this.done) { |
| throw new NoSuchElementException(); |
| } |
| this.done = true; |
| return this.element; |
| } |
| |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public String toString() { |
| return StringTools.buildToStringFor(this, this.element); |
| } |
| |
| } |