| /* |
| * Copyright 1999-2004 The Apache Software Foundation |
| * |
| * Licensed 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.collections.iterators; |
| |
| import java.lang.reflect.Array; |
| import java.util.NoSuchElementException; |
| |
| import org.apache.commons.collections.ResettableIterator; |
| |
| /** |
| * Implements an {@link java.util.Iterator Iterator} over any array. |
| * <p> |
| * The array can be either an array of object or of primitives. If you know |
| * that you have an object array, the |
| * {@link org.apache.commons.collections.iterators.ObjectArrayIterator ObjectArrayIterator} |
| * class is a better choice, as it will perform better. |
| * <p> |
| * The iterator implements a {@link #reset} method, allowing the reset of |
| * the iterator back to the start if required. |
| * |
| * @since Commons Collections 1.0 |
| * @version $Revision: 1.1 $ $Date: 2009/05/27 22:16:27 $ |
| * |
| * @author James Strachan |
| * @author Mauricio S. Moura |
| * @author Michael A. Smith |
| * @author Neil O'Toole |
| * @author Stephen Colebourne |
| */ |
| public class ArrayIterator implements ResettableIterator { |
| |
| /** The array to iterate over */ |
| protected Object array; |
| /** The start index to loop from */ |
| protected int startIndex = 0; |
| /** The end index to loop to */ |
| protected int endIndex = 0; |
| /** The current iterator index */ |
| protected int index = 0; |
| |
| // Constructors |
| // ---------------------------------------------------------------------- |
| /** |
| * Constructor for use with <code>setArray</code>. |
| * <p> |
| * Using this constructor, the iterator is equivalent to an empty iterator |
| * until {@link #setArray(Object)} is called to establish the array to iterate over. |
| */ |
| public ArrayIterator() { |
| super(); |
| } |
| |
| /** |
| * Constructs an ArrayIterator that will iterate over the values in the |
| * specified array. |
| * |
| * @param array the array to iterate over. |
| * @throws IllegalArgumentException if <code>array</code> is not an array. |
| * @throws NullPointerException if <code>array</code> is <code>null</code> |
| */ |
| public ArrayIterator(final Object array) { |
| super(); |
| setArray(array); |
| } |
| |
| /** |
| * Constructs an ArrayIterator that will iterate over the values in the |
| * specified array from a specific start index. |
| * |
| * @param array the array to iterate over. |
| * @param startIndex the index to start iterating at. |
| * @throws IllegalArgumentException if <code>array</code> is not an array. |
| * @throws NullPointerException if <code>array</code> is <code>null</code> |
| * @throws IndexOutOfBoundsException if the index is invalid |
| */ |
| public ArrayIterator(final Object array, final int startIndex) { |
| super(); |
| setArray(array); |
| checkBound(startIndex, "start"); |
| this.startIndex = startIndex; |
| this.index = startIndex; |
| } |
| |
| /** |
| * Construct an ArrayIterator that will iterate over a range of values |
| * in the specified array. |
| * |
| * @param array the array to iterate over. |
| * @param startIndex the index to start iterating at. |
| * @param endIndex the index to finish iterating at. |
| * @throws IllegalArgumentException if <code>array</code> is not an array. |
| * @throws NullPointerException if <code>array</code> is <code>null</code> |
| * @throws IndexOutOfBoundsException if either index is invalid |
| */ |
| public ArrayIterator(final Object array, final int startIndex, final int endIndex) { |
| super(); |
| setArray(array); |
| checkBound(startIndex, "start"); |
| checkBound(endIndex, "end"); |
| if (endIndex < startIndex) { |
| throw new IllegalArgumentException("End index must not be less than start index."); |
| } |
| this.startIndex = startIndex; |
| this.endIndex = endIndex; |
| this.index = startIndex; |
| } |
| |
| /** |
| * Checks whether the index is valid or not. |
| * |
| * @param bound the index to check |
| * @param type the index type (for error messages) |
| * @throws IndexOutOfBoundsException if the index is invalid |
| */ |
| protected void checkBound(final int bound, final String type ) { |
| if (bound > this.endIndex) { |
| throw new ArrayIndexOutOfBoundsException( |
| "Attempt to make an ArrayIterator that " + type + |
| "s beyond the end of the array. " |
| ); |
| } |
| if (bound < 0) { |
| throw new ArrayIndexOutOfBoundsException( |
| "Attempt to make an ArrayIterator that " + type + |
| "s before the start of the array. " |
| ); |
| } |
| } |
| |
| // Iterator interface |
| //----------------------------------------------------------------------- |
| /** |
| * Returns true if there are more elements to return from the array. |
| * |
| * @return true if there is a next element to return |
| */ |
| public boolean hasNext() { |
| return (index < endIndex); |
| } |
| |
| /** |
| * Returns the next element in the array. |
| * |
| * @return the next element in the array |
| * @throws NoSuchElementException if all the elements in the array |
| * have already been returned |
| */ |
| public Object next() { |
| if (hasNext() == false) { |
| throw new NoSuchElementException(); |
| } |
| return Array.get(array, index++); |
| } |
| |
| /** |
| * Throws {@link UnsupportedOperationException}. |
| * |
| * @throws UnsupportedOperationException always |
| */ |
| public void remove() { |
| throw new UnsupportedOperationException("remove() method is not supported"); |
| } |
| |
| // Properties |
| //----------------------------------------------------------------------- |
| /** |
| * Gets the array that this iterator is iterating over. |
| * |
| * @return the array this iterator iterates over, or <code>null</code> if |
| * the no-arg constructor was used and {@link #setArray(Object)} has never |
| * been called with a valid array. |
| */ |
| public Object getArray() { |
| return array; |
| } |
| |
| /** |
| * Sets the array that the ArrayIterator should iterate over. |
| * <p> |
| * If an array has previously been set (using the single-arg constructor |
| * or this method) then that array is discarded in favour of this one. |
| * Iteration is restarted at the start of the new array. |
| * Although this can be used to reset iteration, the {@link #reset()} method |
| * is a more effective choice. |
| * |
| * @param array the array that the iterator should iterate over. |
| * @throws IllegalArgumentException if <code>array</code> is not an array. |
| * @throws NullPointerException if <code>array</code> is <code>null</code> |
| */ |
| public void setArray(final Object array) { |
| // Array.getLength throws IllegalArgumentException if the object is not |
| // an array or NullPointerException if the object is null. This call |
| // is made before saving the array and resetting the index so that the |
| // array iterator remains in a consistent state if the argument is not |
| // an array or is null. |
| this.endIndex = Array.getLength(array); |
| this.startIndex = 0; |
| this.array = array; |
| this.index = 0; |
| } |
| |
| /** |
| * Resets the iterator back to the start index. |
| */ |
| public void reset() { |
| this.index = this.startIndex; |
| } |
| |
| } |