001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the "License");
007 * you may not use this file except in compliance with the License.
008 * You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 /*
019 * $Id: ChildTestIterator.java 468655 2006-10-28 07:12:06Z minchau $
020 */
021 package org.apache.xpath.axes;
022
023 import org.apache.xml.dtm.Axis;
024 import org.apache.xml.dtm.DTM;
025 import org.apache.xml.dtm.DTMAxisTraverser;
026 import org.apache.xml.dtm.DTMIterator;
027 import org.apache.xpath.compiler.Compiler;
028
029 /**
030 * This class implements an optimized iterator for
031 * children patterns that have a node test, and possibly a predicate.
032 * @see org.apache.xpath.axes.BasicTestIterator
033 * @xsl.usage advanced
034 */
035 public class ChildTestIterator extends BasicTestIterator
036 {
037 static final long serialVersionUID = -7936835957960705722L;
038 /** The traverser to use to navigate over the descendants. */
039 transient protected DTMAxisTraverser m_traverser;
040
041 /** The extended type ID, not set until setRoot. */
042 // protected int m_extendedTypeID;
043
044
045 /**
046 * Create a ChildTestIterator object.
047 *
048 * @param compiler A reference to the Compiler that contains the op map.
049 * @param opPos The position within the op map, which contains the
050 * location path expression for this itterator.
051 *
052 * @throws javax.xml.transform.TransformerException
053 */
054 ChildTestIterator(Compiler compiler, int opPos, int analysis)
055 throws javax.xml.transform.TransformerException
056 {
057 super(compiler, opPos, analysis);
058 }
059
060 /**
061 * Create a ChildTestIterator object.
062 *
063 * @param traverser Traverser that tells how the KeyIterator is to be handled.
064 *
065 * @throws javax.xml.transform.TransformerException
066 */
067 public ChildTestIterator(DTMAxisTraverser traverser)
068 {
069
070 super(null);
071
072 m_traverser = traverser;
073 }
074
075 /**
076 * Get the next node via getNextXXX. Bottlenecked for derived class override.
077 * @return The next node on the axis, or DTM.NULL.
078 */
079 protected int getNextNode()
080 {
081 if(true /* 0 == m_extendedTypeID */)
082 {
083 m_lastFetched = (DTM.NULL == m_lastFetched)
084 ? m_traverser.first(m_context)
085 : m_traverser.next(m_context, m_lastFetched);
086 }
087 // else
088 // {
089 // m_lastFetched = (DTM.NULL == m_lastFetched)
090 // ? m_traverser.first(m_context, m_extendedTypeID)
091 // : m_traverser.next(m_context, m_lastFetched,
092 // m_extendedTypeID);
093 // }
094
095 return m_lastFetched;
096 }
097
098
099 /**
100 * Get a cloned Iterator that is reset to the beginning
101 * of the query.
102 *
103 * @return A cloned NodeIterator set of the start of the query.
104 *
105 * @throws CloneNotSupportedException
106 */
107 public DTMIterator cloneWithReset() throws CloneNotSupportedException
108 {
109
110 ChildTestIterator clone = (ChildTestIterator) super.cloneWithReset();
111 clone.m_traverser = m_traverser;
112
113 return clone;
114 }
115
116
117 /**
118 * Initialize the context values for this expression
119 * after it is cloned.
120 *
121 * @param context The XPath runtime context for this
122 * transformation.
123 */
124 public void setRoot(int context, Object environment)
125 {
126 super.setRoot(context, environment);
127 m_traverser = m_cdtm.getAxisTraverser(Axis.CHILD);
128
129 // String localName = getLocalName();
130 // String namespace = getNamespace();
131 // int what = m_whatToShow;
132 // // System.out.println("what: ");
133 // // NodeTest.debugWhatToShow(what);
134 // if(DTMFilter.SHOW_ALL == what ||
135 // ((DTMFilter.SHOW_ELEMENT & what) == 0)
136 // || localName == NodeTest.WILD
137 // || namespace == NodeTest.WILD)
138 // {
139 // m_extendedTypeID = 0;
140 // }
141 // else
142 // {
143 // int type = getNodeTypeTest(what);
144 // m_extendedTypeID = m_cdtm.getExpandedTypeID(namespace, localName, type);
145 // }
146
147 }
148
149 /**
150 * Returns the axis being iterated, if it is known.
151 *
152 * @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple
153 * types.
154 */
155 public int getAxis()
156 {
157 return org.apache.xml.dtm.Axis.CHILD;
158 }
159
160 /**
161 * Detaches the iterator from the set which it iterated over, releasing
162 * any computational resources and placing the iterator in the INVALID
163 * state. After<code>detach</code> has been invoked, calls to
164 * <code>nextNode</code> or<code>previousNode</code> will raise the
165 * exception INVALID_STATE_ERR.
166 */
167 public void detach()
168 {
169 if(m_allowDetach)
170 {
171 m_traverser = null;
172
173 // Always call the superclass detach last!
174 super.detach();
175 }
176 }
177
178 }