| /* |
| * @(#)$Id$ |
| * |
| * The Apache Software License, Version 1.1 |
| * |
| * |
| * Copyright (c) 2001 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation and was |
| * originally based on software copyright (c) 2001, Sun |
| * Microsystems., http://www.sun.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| * @author Jacek Ambroziak |
| * @author Santiago Pericas-Geertsen |
| * |
| */ |
| |
| package org.apache.xalan.xsltc.dom; |
| |
| import org.apache.xalan.xsltc.DOM; |
| import org.apache.xalan.xsltc.NodeIterator; |
| import org.apache.xalan.xsltc.runtime.BasisLibrary; |
| |
| /** |
| * UnionIterator takes a set of NodeIterators and produces |
| * a merged NodeSet in document order with duplicates removed |
| * The individual iterators are supposed to generate nodes |
| * in document order |
| */ |
| public final class UnionIterator extends NodeIteratorBase { |
| /** wrapper for NodeIterators to support iterator |
| comparison on the value of their next() method |
| */ |
| final private DOM _dom; |
| |
| private final static class LookAheadIterator { |
| public int node, markedNode; |
| public final NodeIterator iterator; |
| |
| public LookAheadIterator(NodeIterator iterator) { |
| this.iterator = iterator; |
| } |
| |
| public int step() { |
| node = iterator.next(); |
| return node; |
| } |
| |
| public void setMark() { |
| markedNode = node; |
| iterator.setMark(); |
| } |
| |
| public void gotoMark() { |
| node = markedNode; |
| iterator.gotoMark(); |
| } |
| |
| } // end of LookAheadIterator |
| |
| private static final int InitSize = 8; |
| |
| private int _heapSize = 0; |
| private int _size = InitSize; |
| private LookAheadIterator[] _heap = new LookAheadIterator[InitSize]; |
| private int _free = 0; |
| |
| // last node returned by this UnionIterator to the caller of next |
| // used to prune duplicates |
| private int _returnedLast; |
| |
| public UnionIterator(DOM dom) { |
| _dom = dom; |
| } |
| |
| public NodeIterator cloneIterator() { |
| _isRestartable = false; |
| final LookAheadIterator[] heapCopy = |
| new LookAheadIterator[_heap.length]; |
| try { |
| final UnionIterator clone = (UnionIterator)super.clone(); |
| System.arraycopy(_heap, 0, heapCopy, 0, _heap.length); |
| clone._heap = heapCopy; |
| return clone.reset(); |
| } |
| catch (CloneNotSupportedException e) { |
| BasisLibrary.runTimeError("Iterator clone not supported."); |
| return null; |
| } |
| } |
| |
| public UnionIterator addIterator(NodeIterator iterator) { |
| if (_free == _size) { |
| LookAheadIterator[] newArray = new LookAheadIterator[_size *= 2]; |
| System.arraycopy(_heap, 0, newArray, 0, _free); |
| _heap = newArray; |
| } |
| _heapSize++; |
| _heap[_free++] = new LookAheadIterator(iterator); |
| return this; |
| } |
| |
| public int next() { |
| while (_heapSize > 0) { |
| final int smallest = _heap[0].node; |
| if (smallest == END) { // iterator _heap[0] is done |
| if (_heapSize > 1) { |
| // replace it with last |
| _heap[0] = _heap[--_heapSize]; |
| } |
| else { |
| return END; |
| } |
| } |
| else if (smallest == _returnedLast) { // duplicate |
| _heap[0].step(); // value consumed |
| } |
| else { |
| _heap[0].step(); // value consumed |
| heapify(0); |
| return returnNode(_returnedLast = smallest); |
| } |
| // fallthrough if not returned above |
| heapify(0); |
| } |
| return END; |
| } |
| |
| public NodeIterator setStartNode(int node) { |
| if (_isRestartable) { |
| _startNode = node; |
| for (int i = 0; i < _free; i++) { |
| _heap[i].iterator.setStartNode(node); |
| _heap[i].step(); // to get the first node |
| } |
| // build heap |
| for (int i = (_heapSize = _free)/2; i >= 0; i--) { |
| heapify(i); |
| } |
| _returnedLast = END; |
| return resetPosition(); |
| } |
| return this; |
| } |
| |
| private void heapify(int i) { |
| for (int r, l, smallest;;) { |
| r = (i + 1) << 1; l = r - 1; |
| smallest = l < _heapSize |
| && _dom.lessThan(_heap[l].node, _heap[i].node) ? l : i; |
| if (r < _heapSize && _dom.lessThan(_heap[r].node, |
| _heap[smallest].node)) { |
| smallest = r; |
| } |
| if (smallest != i) { |
| final LookAheadIterator temp = _heap[smallest]; |
| _heap[smallest] = _heap[i]; |
| _heap[i] = temp; |
| i = smallest; |
| } |
| else |
| break; |
| } |
| } |
| |
| public void setMark() { |
| for (int i = 0; i < _free; i++) { |
| _heap[i].setMark(); |
| } |
| } |
| |
| public void gotoMark() { |
| for (int i = 0; i < _free; i++) { |
| _heap[i].gotoMark(); |
| } |
| } |
| |
| public NodeIterator reset() { |
| super.reset(); |
| for (int i = 0; i < _free; i++) { |
| _heap[i].iterator.reset(); |
| } |
| return(this); |
| } |
| |
| } |