package ca.ubc.cs.spl.aspectPatterns.examples.iterator.java;
/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This file is part of the design patterns project at UBC
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* either http://www.mozilla.org/MPL/ or http://aspectj.org/MPL/.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is ca.ubc.cs.spl.aspectPatterns.
*
* For more details and the latest version of this code, please see:
* http://www.cs.ubc.ca/labs/spl/projects/aodps.html
*
* Contributor(s):
*/
import java.util.Iterator;
/**
* Implements a reverse iterator. This means that it will return elements in
* reverse order. We chose not to define our own <i>Iterator</i>, but to use
* Java's <code>java.util.Iterator</code> interface.
*
* @author Jan Hannemann
* @author Gregor Kiczales
* @version 1.1, 02/12/04
*/
public class ReverseIterator implements Iterator {
/**
* the positition of the current element
*/
protected int current;
/**
* the list this iterator operates on
*/
protected SimpleList list;
/**
* Returns true if the iteration has more elements.
*
* @return true if the iteration has more elements
*/
public boolean hasNext() {
return (current > 0);
}
/**
* This opional method is not implemented for this iterator.
*/
public void remove() {
throw new UnsupportedOperationException("remove() not supported");
}
/**
* Returns the next element in the iteration.
*
* @return the next element in the iteration.
*/
public Object next() {
if (!hasNext()) {
throw new ArrayIndexOutOfBoundsException("Iterator out of Bounds");
} else {
return list.get(--current);
}
}
/**
* Creates a new ReverseIterator from the given list.
*
* @param list the list to generate an iterator from
*/
public ReverseIterator(SimpleList list) {
super();
this.list = list;
current = list.count();
}
}