1 /* 2 * reserved comment block 3 * DO NOT REMOVE OR ALTER! 4 */ 5 /* 6 * Copyright 2001-2004 The Apache Software Foundation. 7 * 8 * Licensed under the Apache License, Version 2.0 (the "License"); 9 * you may not use this file except in compliance with the License. 10 * You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, software 15 * distributed under the License is distributed on an "AS IS" BASIS, 16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 17 * See the License for the specific language governing permissions and 18 * limitations under the License. 19 */ 20 /* 21 * $Id: MatchingIterator.java,v 1.2.4.1 2005/09/06 09:22:07 pvedula Exp $ 22 */ 23 24 package com.sun.org.apache.xalan.internal.xsltc.dom; 25 26 import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary; 27 import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator; 28 import com.sun.org.apache.xml.internal.dtm.ref.DTMAxisIteratorBase; 29 30 /** 31 * This is a special kind of iterator that takes a source iterator and a 32 * node N. If initialized with a node M (the parent of N) it computes the 33 * position of N amongst the children of M. This position can be obtained 34 * by calling getPosition(). 35 * It is an iterator even though next() will never be called. It is used to 36 * match patterns with a single predicate like: 37 * 38 * BOOK[position() = last()] 39 * 40 * In this example, the source iterator will return elements of type BOOK, 41 * a call to position() will return the position of N. Notice that because 42 * of the way the pattern matching is implemented, N will always be a node 43 * in the source since (i) it is a BOOK or the test sequence would not be 44 * considered and (ii) the source iterator is initialized with M which is 45 * the parent of N. Also, and still in this example, a call to last() will 46 * return the number of elements in the source (i.e. the number of BOOKs). 47 * @author Jacek Ambroziak 48 * @author Santiago Pericas-Geertsen 49 */ 50 public final class MatchingIterator extends DTMAxisIteratorBase { 51 52 /** 53 * A reference to a source iterator. 54 */ 55 private DTMAxisIterator _source; 56 57 /** 58 * The node to match. 59 */ 60 private final int _match; 61 MatchingIterator(int match, DTMAxisIterator source)62 public MatchingIterator(int match, DTMAxisIterator source) { 63 _source = source; 64 _match = match; 65 } 66 67 setRestartable(boolean isRestartable)68 public void setRestartable(boolean isRestartable) { 69 _isRestartable = isRestartable; 70 _source.setRestartable(isRestartable); 71 } 72 cloneIterator()73 public DTMAxisIterator cloneIterator() { 74 75 try { 76 final MatchingIterator clone = (MatchingIterator) super.clone(); 77 clone._source = _source.cloneIterator(); 78 clone._isRestartable = false; 79 return clone.reset(); 80 } 81 catch (CloneNotSupportedException e) { 82 BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR, 83 e.toString()); 84 return null; 85 } 86 } 87 setStartNode(int node)88 public DTMAxisIterator setStartNode(int node) { 89 if (_isRestartable) { 90 // iterator is not a clone 91 _source.setStartNode(node); 92 93 // Calculate the position of the node in the set 94 _position = 1; 95 while ((node = _source.next()) != END && node != _match) { 96 _position++; 97 } 98 } 99 return this; 100 } 101 reset()102 public DTMAxisIterator reset() { 103 _source.reset(); 104 return resetPosition(); 105 } 106 next()107 public int next() { 108 return _source.next(); 109 } 110 getLast()111 public int getLast() { 112 if (_last == -1) { 113 _last = _source.getLast(); 114 } 115 return _last; 116 } 117 getPosition()118 public int getPosition() { 119 return _position; 120 } 121 setMark()122 public void setMark() { 123 _source.setMark(); 124 } 125 gotoMark()126 public void gotoMark() { 127 _source.gotoMark(); 128 } 129 } 130