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: AVTPartXPath.java 468643 2006-10-28 06:56:03Z minchau $
020 */
021 package org.apache.xalan.templates;
022
023 import org.apache.xml.utils.FastStringBuffer;
024 import org.apache.xpath.XPath;
025 import org.apache.xpath.XPathContext;
026 import org.apache.xpath.XPathFactory;
027 import org.apache.xpath.compiler.XPathParser;
028 import org.apache.xpath.objects.XObject;
029
030 /**
031 * Simple string part of a complex AVT.
032 * @xsl.usage internal
033 */
034 public class AVTPartXPath extends AVTPart
035 {
036 static final long serialVersionUID = -4460373807550527675L;
037
038 /**
039 * The XPath object contained in this part.
040 * @serial
041 */
042 private XPath m_xpath;
043
044 /**
045 * This function is used to fixup variables from QNames to stack frame
046 * indexes at stylesheet build time.
047 * @param vars List of QNames that correspond to variables. This list
048 * should be searched backwards for the first qualified name that
049 * corresponds to the variable reference qname. The position of the
050 * QName in the vector from the start of the vector will be its position
051 * in the stack frame (but variables above the globalsTop value will need
052 * to be offset to the current stack frame).
053 */
054 public void fixupVariables(java.util.Vector vars, int globalsSize)
055 {
056 m_xpath.fixupVariables(vars, globalsSize);
057 }
058
059 /**
060 * Tell if this expression or it's subexpressions can traverse outside
061 * the current subtree.
062 *
063 * @return true if traversal outside the context node's subtree can occur.
064 */
065 public boolean canTraverseOutsideSubtree()
066 {
067 return m_xpath.getExpression().canTraverseOutsideSubtree();
068 }
069
070 /**
071 * Construct a simple AVT part.
072 *
073 * @param xpath Xpath section of AVT
074 */
075 public AVTPartXPath(XPath xpath)
076 {
077 m_xpath = xpath;
078 }
079
080 /**
081 * Construct a simple AVT part.
082 *
083 * @param val A pure string section of an AVT.
084 * @param nsNode An object which can be used to determine the
085 * Namespace Name (URI) for any Namespace prefix used in the XPath.
086 * Usually this is based on the context where the XPath was specified,
087 * such as a node within a Stylesheet.
088 * @param xpathProcessor XPath parser
089 * @param factory XPath factory
090 * @param liaison An XPathContext object, providing infomation specific
091 * to this invocation and this thread. Maintains SAX output state,
092 * variables, error handler and so on, so the transformation/XPath
093 * object itself can be simultaneously invoked from multiple threads.
094 *
095 * @throws javax.xml.transform.TransformerException
096 * TODO: Fix or remove this unused c'tor.
097 */
098 public AVTPartXPath(
099 String val, org.apache.xml.utils.PrefixResolver nsNode,
100 XPathParser xpathProcessor, XPathFactory factory,
101 XPathContext liaison)
102 throws javax.xml.transform.TransformerException
103 {
104 m_xpath = new XPath(val, null, nsNode, XPath.SELECT, liaison.getErrorListener());
105 }
106
107 /**
108 * Get the AVT part as the original string.
109 *
110 * @return the AVT part as the original string.
111 */
112 public String getSimpleString()
113 {
114 return "{" + m_xpath.getPatternString() + "}";
115 }
116
117 /**
118 * Write the value into the buffer.
119 *
120 * @param xctxt An XPathContext object, providing infomation specific
121 * to this invocation and this thread. Maintains SAX state, variables,
122 * error handler and so on, so the transformation/XPath object itself
123 * can be simultaneously invoked from multiple threads.
124 * @param buf Buffer to write into.
125 * @param context The current source tree context.
126 * @param nsNode The current namespace context (stylesheet tree context).
127 *
128 * @throws javax.xml.transform.TransformerException
129 */
130 public void evaluate(
131 XPathContext xctxt, FastStringBuffer buf, int context, org.apache.xml.utils.PrefixResolver nsNode)
132 throws javax.xml.transform.TransformerException
133 {
134
135 XObject xobj = m_xpath.execute(xctxt, context, nsNode);
136
137 if (null != xobj)
138 {
139 xobj.appendToFsb(buf);
140 }
141 }
142
143 /**
144 * @see XSLTVisitable#callVisitors(XSLTVisitor)
145 */
146 public void callVisitors(XSLTVisitor visitor)
147 {
148 m_xpath.getExpression().callVisitors(m_xpath, visitor);
149 }
150 }