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 018package org.apache.commons.jexl3.internal.introspection; 019 020import java.lang.reflect.Array; 021import java.util.Iterator; 022import java.util.NoSuchElementException; 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 */ 040public class ArrayIterator implements Iterator<Object> { 041 /** The objects to iterate over. */ 042 private final Object array; 043 /** The size of the array. */ 044 private final int size; 045 /** The current position and size in the array. */ 046 private int pos; 047 048 /** 049 * Creates a new iterator instance for the specified array. 050 * @param arr The array for which an iterator is desired. 051 */ 052 public ArrayIterator(final Object arr) { 053 if (arr == null) { 054 array = null; 055 pos = 0; 056 size = 0; 057 } else if (!arr.getClass().isArray()) { 058 throw new IllegalArgumentException(arr.getClass() + " is not an array"); 059 } else { 060 array = arr; 061 pos = 0; 062 size = Array.getLength(array); 063 } 064 } 065 066 /** 067 * Move to next element in the array. 068 * 069 * @return The next object in the array. 070 */ 071 @Override 072 public Object next() { 073 if (pos < size) { 074 return Array.get(array, pos++); 075 } 076 // we screwed up... 077 throw new NoSuchElementException("No more elements: " + pos 078 + " / " + size); 079 } 080 081 /** 082 * Check to see if there is another element in the array. 083 * 084 * @return Whether there is another element. 085 */ 086 @Override 087 public boolean hasNext() { 088 return (pos < size); 089 } 090 091 /** 092 * No op--merely added to satify the <code>Iterator</code> interface. 093 */ 094 @Override 095 public void remove() { 096 throw new UnsupportedOperationException(); 097 } 098}