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: ElemValueOf.java 468643 2006-10-28 06:56:03Z minchau $
20 */
21package org.apache.xalan.templates;
22
23import javax.xml.transform.TransformerException;
24
25import org.apache.xalan.res.XSLTErrorResources;
26import org.apache.xalan.transformer.TransformerImpl;
27import org.apache.xml.dtm.DTM;
28import org.apache.xml.serializer.SerializationHandler;
29import org.apache.xpath.Expression;
30import org.apache.xpath.XPath;
31import org.apache.xpath.XPathContext;
32import org.apache.xpath.objects.XObject;
33import org.xml.sax.SAXException;
34
35/**
36 * Implement xsl:value-of.
37 * <pre>
38 * <!ELEMENT xsl:value-of EMPTY>
39 * <!ATTLIST xsl:value-of
40 *   select %expr; #REQUIRED
41 *   disable-output-escaping (yes|no) "no"
42 * >
43 * </pre>
44 * @see <a href="http://www.w3.org/TR/xslt#value-of">value-of in XSLT Specification</a>
45 * @xsl.usage advanced
46 */
47public class ElemValueOf extends ElemTemplateElement
48{
49    static final long serialVersionUID = 3490728458007586786L;
50
51  /**
52   * The select expression to be executed.
53   * @serial
54   */
55  private XPath m_selectExpression = null;
56
57  /**
58   * True if the pattern is a simple ".".
59   * @serial
60   */
61  private boolean m_isDot = false;
62
63  /**
64   * Set the "select" attribute.
65   * The required select attribute is an expression; this expression
66   * is evaluated and the resulting object is converted to a
67   * string as if by a call to the string function.
68   *
69   * @param v The value to set for the "select" attribute.
70   */
71  public void setSelect(XPath v)
72  {
73
74    if (null != v)
75    {
76      String s = v.getPatternString();
77
78      m_isDot = (null != s) && s.equals(".");
79    }
80
81    m_selectExpression = v;
82  }
83
84  /**
85   * Get the "select" attribute.
86   * The required select attribute is an expression; this expression
87   * is evaluated and the resulting object is converted to a
88   * string as if by a call to the string function.
89   *
90   * @return The value of the "select" attribute.
91   */
92  public XPath getSelect()
93  {
94    return m_selectExpression;
95  }
96
97  /**
98   * Tells if this element should disable escaping.
99   * @serial
100   */
101  private boolean m_disableOutputEscaping = false;
102
103  /**
104   * Set the "disable-output-escaping" attribute.
105   * Normally, the xml output method escapes & and < (and
106   * possibly other characters) when outputting text nodes.
107   * This ensures that the output is well-formed XML. However,
108   * it is sometimes convenient to be able to produce output
109   * that is almost, but not quite well-formed XML; for
110   * example, the output may include ill-formed sections
111   * which are intended to be transformed into well-formed
112   * XML by a subsequent non-XML aware process. For this reason,
113   * XSLT provides a mechanism for disabling output escaping.
114   * An xsl:value-of or xsl:text element may have a
115   * disable-output-escaping attribute; the allowed values
116   * are yes or no; the default is no; if the value is yes,
117   * then a text node generated by instantiating the xsl:value-of
118   * or xsl:text element should be output without any escaping.
119   * @see <a href="http://www.w3.org/TR/xslt#disable-output-escaping">disable-output-escaping in XSLT Specification</a>
120   *
121   * @param v The value to set for the "disable-output-escaping" attribute.
122   */
123  public void setDisableOutputEscaping(boolean v)
124  {
125    m_disableOutputEscaping = v;
126  }
127
128  /**
129   * Get the "disable-output-escaping" attribute.
130   * Normally, the xml output method escapes & and < (and
131   * possibly other characters) when outputting text nodes.
132   * This ensures that the output is well-formed XML. However,
133   * it is sometimes convenient to be able to produce output
134   * that is almost, but not quite well-formed XML; for
135   * example, the output may include ill-formed sections
136   * which are intended to be transformed into well-formed
137   * XML by a subsequent non-XML aware process. For this reason,
138   * XSLT provides a mechanism for disabling output escaping.
139   * An xsl:value-of or xsl:text element may have a
140   * disable-output-escaping attribute; the allowed values
141   * are yes or no; the default is no; if the value is yes,
142   * then a text node generated by instantiating the xsl:value-of
143   * or xsl:text element should be output without any escaping.
144   * @see <a href="http://www.w3.org/TR/xslt#disable-output-escaping">disable-output-escaping in XSLT Specification</a>
145   *
146   * @return The value of the "disable-output-escaping" attribute.
147   */
148  public boolean getDisableOutputEscaping()
149  {
150    return m_disableOutputEscaping;
151  }
152
153  /**
154   * Get an integer representation of the element type.
155   *
156   * @return An integer representation of the element, defined in the
157   *     Constants class.
158   * @see org.apache.xalan.templates.Constants
159   */
160  public int getXSLToken()
161  {
162    return Constants.ELEMNAME_VALUEOF;
163  }
164
165  /**
166   * This function is called after everything else has been
167   * recomposed, and allows the template to set remaining
168   * values that may be based on some other property that
169   * depends on recomposition.
170   *
171   * NEEDSDOC @param sroot
172   *
173   * @throws TransformerException
174   */
175  public void compose(StylesheetRoot sroot) throws TransformerException
176  {
177
178    super.compose(sroot);
179
180    java.util.Vector vnames = sroot.getComposeState().getVariableNames();
181
182    if (null != m_selectExpression)
183      m_selectExpression.fixupVariables(
184        vnames, sroot.getComposeState().getGlobalsSize());
185  }
186
187  /**
188   * Return the node name.
189   *
190   * @return The node name
191   */
192  public String getNodeName()
193  {
194    return Constants.ELEMNAME_VALUEOF_STRING;
195  }
196
197  /**
198   * Execute the string expression and copy the text to the
199   * result tree.
200   * The required select attribute is an expression; this expression
201   * is evaluated and the resulting object is converted to a string
202   * as if by a call to the string function. The string specifies
203   * the string-value of the created text node. If the string is
204   * empty, no text node will be created. The created text node will
205   * be merged with any adjacent text nodes.
206   * @see <a href="http://www.w3.org/TR/xslt#value-of">value-of in XSLT Specification</a>
207   *
208   * @param transformer non-null reference to the the current transform-time state.
209   *
210   * @throws TransformerException
211   */
212  public void execute(TransformerImpl transformer) throws TransformerException
213  {
214
215    XPathContext xctxt = transformer.getXPathContext();
216    SerializationHandler rth = transformer.getResultTreeHandler();
217
218    try
219    {
220      // Optimize for "."
221        xctxt.pushNamespaceContext(this);
222
223        int current = xctxt.getCurrentNode();
224
225        xctxt.pushCurrentNodeAndExpression(current, current);
226
227        if (m_disableOutputEscaping)
228          rth.processingInstruction(
229            javax.xml.transform.Result.PI_DISABLE_OUTPUT_ESCAPING, "");
230
231        try
232        {
233          Expression expr = m_selectExpression.getExpression();
234
235            expr.executeCharsToContentHandler(xctxt, rth);
236        }
237        finally
238        {
239          if (m_disableOutputEscaping)
240            rth.processingInstruction(
241              javax.xml.transform.Result.PI_ENABLE_OUTPUT_ESCAPING, "");
242
243          xctxt.popNamespaceContext();
244          xctxt.popCurrentNodeAndExpression();
245        }
246    }
247    catch (SAXException se)
248    {
249      throw new TransformerException(se);
250    }
251    catch (RuntimeException re) {
252    	TransformerException te = new TransformerException(re);
253    	te.setLocator(this);
254    	throw te;
255    }
256  }
257
258  /**
259   * Add a child to the child list.
260   *
261   * @param newChild Child to add to children list
262   *
263   * @return Child just added to children list
264   *
265   * @throws DOMException
266   */
267  public ElemTemplateElement appendChild(ElemTemplateElement newChild)
268  {
269
270    error(XSLTErrorResources.ER_CANNOT_ADD,
271          new Object[]{ newChild.getNodeName(),
272                        this.getNodeName() });  //"Can not add " +((ElemTemplateElement)newChild).m_elemName +
273
274    //" to " + this.m_elemName);
275    return null;
276  }
277
278  /**
279   * Call the children visitors.
280   * @param visitor The visitor whose appropriate method will be called.
281   */
282  protected void callChildVisitors(XSLTVisitor visitor, boolean callAttrs)
283  {
284  	if(callAttrs)
285  		m_selectExpression.getExpression().callVisitors(m_selectExpression, visitor);
286    super.callChildVisitors(visitor, callAttrs);
287  }
288
289}
290