001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.jexl2.internal; 019 020 import java.util.Iterator; 021 import java.util.NoSuchElementException; 022 import java.lang.reflect.Array; 023 024 /** 025 * <p> 026 * An Iterator wrapper for an Object[]. This will 027 * allow us to deal with all array like structures 028 * in a consistent manner. 029 * </p> 030 * <p> 031 * WARNING : this class's operations are NOT synchronized. 032 * It is meant to be used in a single thread, newly created 033 * for each use in the #foreach() directive. 034 * If this is used or shared, synchronize in the 035 * next() method. 036 * </p> 037 * 038 * @since 1.0 039 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a> 040 * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a> 041 * @version $Id: ArrayIterator.java 889223 2009-12-10 12:05:22Z henrib $ 042 */ 043 public class ArrayIterator implements Iterator<Object> { 044 /** The objects to iterate over. */ 045 private final Object array; 046 /** The size of the array. */ 047 private final int size; 048 /** The current position and size in the array. */ 049 private int pos; 050 051 /** 052 * Creates a new iterator instance for the specified array. 053 * @param arr The array for which an iterator is desired. 054 */ 055 public ArrayIterator(Object arr) { 056 if (arr == null) { 057 array = null; 058 pos = 0; 059 size = 0; 060 } else if (!arr.getClass().isArray()) { 061 throw new IllegalArgumentException(arr.getClass() + " is not an array"); 062 } else { 063 array = arr; 064 pos = 0; 065 size = Array.getLength(array); 066 } 067 } 068 069 /** 070 * Move to next element in the array. 071 * 072 * @return The next object in the array. 073 */ 074 public Object next() { 075 if (pos < size) { 076 return Array.get(array, pos++); 077 } 078 // we screwed up... 079 throw new NoSuchElementException("No more elements: " + pos 080 + " / " + size); 081 } 082 083 /** 084 * Check to see if there is another element in the array. 085 * 086 * @return Whether there is another element. 087 */ 088 public boolean hasNext() { 089 return (pos < size); 090 } 091 092 /** 093 * No op--merely added to satify the <code>Iterator</code> interface. 094 */ 095 public void remove() { 096 throw new UnsupportedOperationException(); 097 } 098 }