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Types that extend and augment the Java Collections Framework.
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.collections.iterators;
import java.util.ListIterator;
import org.apache.commons.collections.Unmodifiable;
/**
* Decorates a list iterator such that it cannot be modified.
*
* @since Commons Collections 3.0
* @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
*
* @author Stephen Colebourne
*/
public final class UnmodifiableListIterator implements ListIterator, Unmodifiable {
/** The iterator being decorated */
private ListIterator iterator;
//-----------------------------------------------------------------------
/**
* Decorates the specified iterator such that it cannot be modified.
*
* @param iterator the iterator to decorate
* @throws IllegalArgumentException if the iterator is null
*/
public static ListIterator decorate(ListIterator iterator) {
if (iterator == null) {
throw new IllegalArgumentException("ListIterator must not be null");
}
if (iterator instanceof Unmodifiable) {
return iterator;
}
return new UnmodifiableListIterator(iterator);
}
//-----------------------------------------------------------------------
/**
* Constructor.
*
* @param iterator the iterator to decorate
*/
private UnmodifiableListIterator(ListIterator iterator) {
super();
this.iterator = iterator;
}
//-----------------------------------------------------------------------
public boolean hasNext() {
return iterator.hasNext();
}
public Object next() {
return iterator.next();
}
public int nextIndex() {
return iterator.nextIndex();
}
public boolean hasPrevious() {
return iterator.hasPrevious();
}
public Object previous() {
return iterator.previous();
}
public int previousIndex() {
return iterator.previousIndex();
}
public void remove() {
throw new UnsupportedOperationException("remove() is not supported");
}
public void set(Object obj) {
throw new UnsupportedOperationException("set() is not supported");
}
public void add(Object obj) {
throw new UnsupportedOperationException("add() is not supported");
}
}