org.apache.commons.jexl.util.ArrayIterator Maven / Gradle / Ivy
/*
* 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.jexl.util;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.lang.reflect.Array;
/**
*
* An Iterator wrapper for an Object[]. This will
* allow us to deal with all array like structures
* in a consistent manner.
*
*
* WARNING : this class's operations are NOT synchronized.
* It is meant to be used in a single thread, newly created
* for each use in the #foreach() directive.
* If this is used or shared, synchronize in the
* next() method.
*
*
* @since 1.0
* @author Jason van Zyl
* @author Geir Magnusson Jr.
* @version $Id: ArrayIterator.java 480412 2006-11-29 05:11:23Z bayard $
*/
public class ArrayIterator implements Iterator {
/**
* The objects to iterate over.
*/
private final Object array;
/**
* The current position and size in the array.
*/
private int pos;
/**
* The size of the array.
*/
private final int size;
/**
* Creates a new iterator instance for the specified array.
*
* @param arr The array for which an iterator is desired.
*/
public ArrayIterator(Object arr) {
/*
* if this isn't an array, then throw. Note that this is
* for internal use - so this should never happen - if it does
* we screwed up.
*/
if (!arr.getClass().isArray()) {
throw new IllegalArgumentException("Programmer error :"
+ " internal ArrayIterator invoked w/o array");
}
array = arr;
pos = 0;
size = Array.getLength(array);
}
/**
* Move to next element in the array.
*
* @return The next object in the array.
*/
public Object next() {
if (pos < size) {
return Array.get(array, pos++);
}
/*
* we screwed up...
*/
throw new NoSuchElementException("No more elements: " + pos
+ " / " + size);
}
/**
* Check to see if there is another element in the array.
*
* @return Whether there is another element.
*/
public boolean hasNext() {
return (pos < size);
}
/**
* No op--merely added to satify the Iterator interface.
*/
public void remove() {
throw new UnsupportedOperationException();
}
}