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: KeyTable.java 468645 2006-10-28 06:57:24Z minchau $
020 */
021 package org.apache.xalan.transformer;
022
023 import java.util.Hashtable;
024 import java.util.Vector;
025
026 import javax.xml.transform.TransformerException;
027
028 import org.apache.xalan.templates.KeyDeclaration;
029 import org.apache.xml.dtm.DTM;
030 import org.apache.xml.dtm.DTMIterator;
031 import org.apache.xml.utils.PrefixResolver;
032 import org.apache.xml.utils.QName;
033 import org.apache.xml.utils.WrappedRuntimeException;
034 import org.apache.xml.utils.XMLString;
035 import org.apache.xpath.XPathContext;
036 import org.apache.xpath.objects.XNodeSet;
037 import org.apache.xpath.objects.XObject;
038
039 /**
040 * Table of element keys, keyed by document node. An instance of this
041 * class is keyed by a Document node that should be matched with the
042 * root of the current context.
043 * @xsl.usage advanced
044 */
045 public class KeyTable
046 {
047 /**
048 * The document key. This table should only be used with contexts
049 * whose Document roots match this key.
050 */
051 private int m_docKey;
052
053 /**
054 * Vector of KeyDeclaration instances holding the key declarations.
055 */
056 private Vector m_keyDeclarations;
057
058 /**
059 * Hold a cache of key() function result for each ref.
060 * Key is XMLString, the ref value
061 * Value is XNodeSet, the key() function result for the given ref value.
062 */
063 private Hashtable m_refsTable = null;
064
065 /**
066 * Get the document root matching this key.
067 *
068 * @return the document root matching this key
069 */
070 public int getDocKey()
071 {
072 return m_docKey;
073 }
074
075 /**
076 * The main iterator that will walk through the source
077 * tree for this key.
078 */
079 private XNodeSet m_keyNodes;
080
081 KeyIterator getKeyIterator()
082 {
083 return (KeyIterator)(m_keyNodes.getContainedIter());
084 }
085
086 /**
087 * Build a keys table.
088 * @param doc The owner document key.
089 * @param nscontext The stylesheet's namespace context.
090 * @param name The key name
091 * @param keyDeclarations The stylesheet's xsl:key declarations.
092 *
093 * @throws javax.xml.transform.TransformerException
094 */
095 public KeyTable(
096 int doc, PrefixResolver nscontext, QName name, Vector keyDeclarations, XPathContext xctxt)
097 throws javax.xml.transform.TransformerException
098 {
099 m_docKey = doc;
100 m_keyDeclarations = keyDeclarations;
101 KeyIterator ki = new KeyIterator(name, keyDeclarations);
102
103 m_keyNodes = new XNodeSet(ki);
104 m_keyNodes.allowDetachToRelease(false);
105 m_keyNodes.setRoot(doc, xctxt);
106 }
107
108 /**
109 * Given a valid element key, return the corresponding node list.
110 *
111 * @param name The name of the key, which must match the 'name' attribute on xsl:key.
112 * @param ref The value that must match the value found by the 'match' attribute on xsl:key.
113 * @return a set of nodes referenced by the key named <CODE>name</CODE> and the reference <CODE>ref</CODE>. If no node is referenced by this key, an empty node set is returned.
114 */
115 public XNodeSet getNodeSetDTMByKey(QName name, XMLString ref)
116
117 {
118 XNodeSet refNodes = (XNodeSet) getRefsTable().get(ref);
119 // clone wiht reset the node set
120 try
121 {
122 if (refNodes != null)
123 {
124 refNodes = (XNodeSet) refNodes.cloneWithReset();
125 }
126 }
127 catch (CloneNotSupportedException e)
128 {
129 refNodes = null;
130 }
131
132 if (refNodes == null) {
133 // create an empty XNodeSet
134 KeyIterator ki = (KeyIterator) (m_keyNodes).getContainedIter();
135 XPathContext xctxt = ki.getXPathContext();
136 refNodes = new XNodeSet(xctxt.getDTMManager()) {
137 public void setRoot(int nodeHandle, Object environment) {
138 // Root cannot be set on non-iterated node sets. Ignore it.
139 }
140 };
141 refNodes.reset();
142 }
143
144 return refNodes;
145 }
146
147 /**
148 * Get Key Name for this KeyTable
149 *
150 * @return Key name
151 */
152 public QName getKeyTableName()
153 {
154 return getKeyIterator().getName();
155 }
156
157 /**
158 * @return key declarations for the key associated to this KeyTable
159 */
160 private Vector getKeyDeclarations() {
161 int nDeclarations = m_keyDeclarations.size();
162 Vector keyDecls = new Vector(nDeclarations);
163
164 // Walk through each of the declarations made with xsl:key
165 for (int i = 0; i < nDeclarations; i++)
166 {
167 KeyDeclaration kd = (KeyDeclaration) m_keyDeclarations.elementAt(i);
168
169 // Add the declaration if the name on this key declaration
170 // matches the name on the iterator for this walker.
171 if (kd.getName().equals(getKeyTableName())) {
172 keyDecls.add(kd);
173 }
174 }
175
176 return keyDecls;
177 }
178
179 /**
180 * @return lazy initialized refs table associating evaluation of key function
181 * with a XNodeSet
182 */
183 private Hashtable getRefsTable()
184 {
185 if (m_refsTable == null) {
186 // initial capacity set to a prime number to improve hash performance
187 m_refsTable = new Hashtable(89);
188
189 KeyIterator ki = (KeyIterator) (m_keyNodes).getContainedIter();
190 XPathContext xctxt = ki.getXPathContext();
191
192 Vector keyDecls = getKeyDeclarations();
193 int nKeyDecls = keyDecls.size();
194
195 int currentNode;
196 m_keyNodes.reset();
197 while (DTM.NULL != (currentNode = m_keyNodes.nextNode()))
198 {
199 try
200 {
201 for (int keyDeclIdx = 0; keyDeclIdx < nKeyDecls; keyDeclIdx++) {
202 KeyDeclaration keyDeclaration =
203 (KeyDeclaration) keyDecls.elementAt(keyDeclIdx);
204 XObject xuse =
205 keyDeclaration.getUse().execute(xctxt,
206 currentNode,
207 ki.getPrefixResolver());
208
209 if (xuse.getType() != xuse.CLASS_NODESET) {
210 XMLString exprResult = xuse.xstr();
211 addValueInRefsTable(xctxt, exprResult, currentNode);
212 } else {
213 DTMIterator i = ((XNodeSet)xuse).iterRaw();
214 int currentNodeInUseClause;
215
216 while (DTM.NULL != (currentNodeInUseClause = i.nextNode())) {
217 DTM dtm = xctxt.getDTM(currentNodeInUseClause);
218 XMLString exprResult =
219 dtm.getStringValue(currentNodeInUseClause);
220 addValueInRefsTable(xctxt, exprResult, currentNode);
221 }
222 }
223 }
224 } catch (TransformerException te) {
225 throw new WrappedRuntimeException(te);
226 }
227 }
228 }
229 return m_refsTable;
230 }
231
232 /**
233 * Add an association between a ref and a node in the m_refsTable.
234 * Requires that m_refsTable != null
235 * @param xctxt XPath context
236 * @param ref the value of the use clause of the current key for the given node
237 * @param node the node to reference
238 */
239 private void addValueInRefsTable(XPathContext xctxt, XMLString ref, int node) {
240
241 XNodeSet nodes = (XNodeSet) m_refsTable.get(ref);
242 if (nodes == null)
243 {
244 nodes = new XNodeSet(node, xctxt.getDTMManager());
245 nodes.nextNode();
246 m_refsTable.put(ref, nodes);
247 }
248 else
249 {
250 // Nodes are passed to this method in document order. Since we need to
251 // suppress duplicates, we only need to check against the last entry
252 // in each nodeset. We use nodes.nextNode after each entry so we can
253 // easily compare node against the current node.
254 if (nodes.getCurrentNode() != node) {
255 nodes.mutableNodeset().addNode(node);
256 nodes.nextNode();
257 }
258 }
259 }
260 }