| 1 | package org.apache.velocity.util; |
| 2 | |
| 3 | /* |
| 4 | * Copyright 1999-2001,2004 The Apache Software Foundation. |
| 5 | * |
| 6 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 7 | * you may not use this file except in compliance with the License. |
| 8 | * You may obtain a copy of the License at |
| 9 | * |
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 11 | * |
| 12 | * Unless required by applicable law or agreed to in writing, software |
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 15 | * See the License for the specific language governing permissions and |
| 16 | * limitations under the License. |
| 17 | */ |
| 18 | |
| 19 | import java.util.Iterator; |
| 20 | import java.util.NoSuchElementException; |
| 21 | import java.lang.reflect.Array; |
| 22 | |
| 23 | |
| 24 | /** |
| 25 | * <p> |
| 26 | * An Iterator wrapper for an Object[]. This will |
| 27 | * allow us to deal with all array like structures |
| 28 | * in a consistent manner. |
| 29 | * </p> |
| 30 | * <p> |
| 31 | * WARNING : this class's operations are NOT synchronized. |
| 32 | * It is meant to be used in a single thread, newly created |
| 33 | * for each use in the #foreach() directive. |
| 34 | * If this is used or shared, synchronize in the |
| 35 | * next() method. |
| 36 | * </p> |
| 37 | * |
| 38 | * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a> |
| 39 | * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a> |
| 40 | * @version $Id: ArrayIterator.java,v 1.6.8.1 2004/03/03 23:23:07 geirm Exp $ |
| 41 | */ |
| 42 | public class ArrayIterator implements Iterator |
| 43 | { |
| 44 | /** |
| 45 | * The objects to iterate. |
| 46 | */ |
| 47 | private Object array; |
| 48 | |
| 49 | /** |
| 50 | * The current position and size in the array. |
| 51 | */ |
| 52 | private int pos; |
| 53 | private int size; |
| 54 | |
| 55 | /** |
| 56 | * Creates a new iterator instance for the specified array. |
| 57 | * |
| 58 | * @param array The array for which an iterator is desired. |
| 59 | */ |
| 60 | public ArrayIterator(Object array) |
| 61 | { |
| 62 | /* |
| 63 | * if this isn't an array, then throw. Note that this is |
| 64 | * for internal use - so this should never happen - if it does |
| 65 | * we screwed up. |
| 66 | */ |
| 67 | |
| 68 | if ( !array.getClass().isArray() ) |
| 69 | { |
| 70 | throw new IllegalArgumentException( |
| 71 | "Programmer error : internal ArrayIterator invoked w/o array"); |
| 72 | } |
| 73 | |
| 74 | this.array = array; |
| 75 | pos = 0; |
| 76 | size = Array.getLength( this.array ); |
| 77 | } |
| 78 | |
| 79 | /** |
| 80 | * Move to next element in the array. |
| 81 | * |
| 82 | * @return The next object in the array. |
| 83 | */ |
| 84 | public Object next() |
| 85 | { |
| 86 | if (pos < size ) |
| 87 | return Array.get( array, pos++); |
| 88 | |
| 89 | /* |
| 90 | * we screwed up... |
| 91 | */ |
| 92 | |
| 93 | throw new NoSuchElementException("No more elements: " + pos + |
| 94 | " / " + size); |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * Check to see if there is another element in the array. |
| 99 | * |
| 100 | * @return Whether there is another element. |
| 101 | */ |
| 102 | public boolean hasNext() |
| 103 | { |
| 104 | return (pos < size ); |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * No op--merely added to satify the <code>Iterator</code> interface. |
| 109 | */ |
| 110 | public void remove() |
| 111 | { |
| 112 | throw new UnsupportedOperationException(); |
| 113 | } |
| 114 | } |