| /******************************************************************************* |
| * Copyright (c) 2005, 2008 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.ListIterator; |
| import java.util.NoSuchElementException; |
| import org.eclipse.jpt.utility.internal.StringTools; |
| |
| /** |
| * An <code>EmptyListIterator</code> is just that. |
| */ |
| public final class EmptyListIterator<E> |
| implements ListIterator<E> |
| { |
| |
| // singleton |
| @SuppressWarnings("unchecked") |
| private static final EmptyListIterator INSTANCE = new EmptyListIterator(); |
| |
| /** |
| * Return the singleton. |
| */ |
| @SuppressWarnings("unchecked") |
| public static <T> ListIterator<T> instance() { |
| return INSTANCE; |
| } |
| |
| /** |
| * Ensure single instance. |
| */ |
| private EmptyListIterator() { |
| super(); |
| } |
| |
| public void add(E e) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public boolean hasNext() { |
| return false; |
| } |
| |
| public boolean hasPrevious() { |
| return false; |
| } |
| |
| public E next() { |
| throw new NoSuchElementException(); |
| } |
| |
| public int nextIndex() { |
| return 0; |
| } |
| |
| public E previous() { |
| throw new NoSuchElementException(); |
| } |
| |
| public int previousIndex() { |
| return -1; |
| } |
| |
| public void remove() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| public void set(E e) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| @Override |
| public String toString() { |
| return StringTools.buildToStringFor(this); |
| } |
| |
| } |