1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you 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 * $Id: UnionChildIterator.java 468655 2006-10-28 07:12:06Z minchau $ 20 */ 21 package org.apache.xpath.axes; 22 23 import org.apache.xml.dtm.DTMIterator; 24 import org.apache.xpath.XPathContext; 25 import org.apache.xpath.objects.XObject; 26 import org.apache.xpath.patterns.NodeTest; 27 28 /** 29 * This class defines a simplified type of union iterator that only 30 * tests along the child axes. If the conditions are right, it is 31 * much faster than using a UnionPathIterator. 32 */ 33 public class UnionChildIterator extends ChildTestIterator 34 { 35 static final long serialVersionUID = 3500298482193003495L; 36 /** 37 * Even though these may hold full LocPathIterators, this array does 38 * not have to be cloned, since only the node test and predicate 39 * portion are used, and these only need static information. However, 40 * also note that index predicates can not be used! 41 */ 42 private PredicatedNodeTest[] m_nodeTests = null; 43 44 /** 45 * Constructor for UnionChildIterator 46 */ UnionChildIterator()47 public UnionChildIterator() 48 { 49 super(null); 50 } 51 52 /** 53 * Add a node test to the union list. 54 * 55 * @param test reference to a NodeTest, which will be added 56 * directly to the list of node tests (in other words, it will 57 * not be cloned). The parent of this test will be set to 58 * this object. 59 */ addNodeTest(PredicatedNodeTest test)60 public void addNodeTest(PredicatedNodeTest test) 61 { 62 63 // Increase array size by only 1 at a time. Fix this 64 // if it looks to be a problem. 65 if (null == m_nodeTests) 66 { 67 m_nodeTests = new PredicatedNodeTest[1]; 68 m_nodeTests[0] = test; 69 } 70 else 71 { 72 PredicatedNodeTest[] tests = m_nodeTests; 73 int len = m_nodeTests.length; 74 75 m_nodeTests = new PredicatedNodeTest[len + 1]; 76 77 System.arraycopy(tests, 0, m_nodeTests, 0, len); 78 79 m_nodeTests[len] = test; 80 } 81 test.exprSetParent(this); 82 } 83 84 /** 85 * This function is used to fixup variables from QNames to stack frame 86 * indexes at stylesheet build time. 87 * @param vars List of QNames that correspond to variables. This list 88 * should be searched backwards for the first qualified name that 89 * corresponds to the variable reference qname. The position of the 90 * QName in the vector from the start of the vector will be its position 91 * in the stack frame (but variables above the globalsTop value will need 92 * to be offset to the current stack frame). 93 */ fixupVariables(java.util.Vector vars, int globalsSize)94 public void fixupVariables(java.util.Vector vars, int globalsSize) 95 { 96 super.fixupVariables(vars, globalsSize); 97 if (m_nodeTests != null) { 98 for (int i = 0; i < m_nodeTests.length; i++) { 99 m_nodeTests[i].fixupVariables(vars, globalsSize); 100 } 101 } 102 } 103 104 /** 105 * Test whether a specified node is visible in the logical view of a 106 * TreeWalker or NodeIterator. This function will be called by the 107 * implementation of TreeWalker and NodeIterator; it is not intended to 108 * be called directly from user code. 109 * @param n The node to check to see if it passes the filter or not. 110 * @return a constant to determine whether the node is accepted, 111 * rejected, or skipped, as defined above . 112 */ acceptNode(int n)113 public short acceptNode(int n) 114 { 115 XPathContext xctxt = getXPathContext(); 116 try 117 { 118 xctxt.pushCurrentNode(n); 119 for (int i = 0; i < m_nodeTests.length; i++) 120 { 121 PredicatedNodeTest pnt = m_nodeTests[i]; 122 XObject score = pnt.execute(xctxt, n); 123 if (score != NodeTest.SCORE_NONE) 124 { 125 // Note that we are assuming there are no positional predicates! 126 if (pnt.getPredicateCount() > 0) 127 { 128 if (pnt.executePredicates(n, xctxt)) 129 return DTMIterator.FILTER_ACCEPT; 130 } 131 else 132 return DTMIterator.FILTER_ACCEPT; 133 134 } 135 } 136 } 137 catch (javax.xml.transform.TransformerException se) 138 { 139 140 // TODO: Fix this. 141 throw new RuntimeException(se.getMessage()); 142 } 143 finally 144 { 145 xctxt.popCurrentNode(); 146 } 147 return DTMIterator.FILTER_SKIP; 148 } 149 150 } 151