code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  package org.apache.xalan.templates;
  
  import javax.xml.transform.TransformerException;
  
  import org.apache.xalan.res.XSLTErrorResources;
  import org.apache.xalan.transformer.TransformerImpl;
  import org.apache.xml.dtm.DTM;
  import org.apache.xml.serializer.SerializationHandler;
  import org.apache.xpath.Expression;
  import org.apache.xpath.XPath;
  import org.apache.xpath.XPathContext;
  import org.apache.xpath.objects.XObject;
  import org.xml.sax.SAXException;
  
  /**
   * Implement xsl:value-of.
   * <pre>
   * <!ELEMENT xsl:value-of EMPTY>
   * <!ATTLIST xsl:value-of
   *   select %expr; #REQUIRED
   *   disable-output-escaping (yes|no) "no"
   * >
   * </pre>
   * @see <a href="http://www.w3.org/TR/xslt#value-of">value-of in XSLT Specification</a>
   * @xsl.usage advanced
   */
  public class ElemValueOf extends ElemTemplateElement
  {
      static final long serialVersionUID = 3490728458007586786L;
  
    /**
     * The select expression to be executed.
     * @serial
     */
    private XPath m_selectExpression = null;
  
    /**
     * True if the pattern is a simple ".".
     * @serial
     */
    private boolean m_isDot = false;
  
    /**
     * Set the "select" attribute.
     * The required select attribute is an expression; this expression
     * is evaluated and the resulting object is converted to a
     * string as if by a call to the string function.
     *
     * @param v The value to set for the "select" attribute.
     */
    public void setSelect(XPath v)
    {
  
      if (null != v)
      {
        String s = v.getPatternString();
  
        m_isDot = (null != s) && s.equals(".");
      }
  
      m_selectExpression = v;
    }
  
    /**
     * Get the "select" attribute.
     * The required select attribute is an expression; this expression
     * is evaluated and the resulting object is converted to a
     * string as if by a call to the string function.
     *
     * @return The value of the "select" attribute.
     */
    public XPath getSelect()
    {
      return m_selectExpression;
    }
  
    /**
     * Tells if this element should disable escaping.
     * @serial
     */
    private boolean m_disableOutputEscaping = false;
  
    /**
     * Set the "disable-output-escaping" attribute.
     * Normally, the xml output method escapes & and < (and
     * possibly other characters) when outputting text nodes.
     * This ensures that the output is well-formed XML. However,
     * it is sometimes convenient to be able to produce output
     * that is almost, but not quite well-formed XML; for
     * example, the output may include ill-formed sections
     * which are intended to be transformed into well-formed
     * XML by a subsequent non-XML aware process. For this reason,
     * XSLT provides a mechanism for disabling output escaping.
     * An xsl:value-of or xsl:text element may have a
     * disable-output-escaping attribute; the allowed values
     * are yes or no; the default is no; if the value is yes,
     * then a text node generated by instantiating the xsl:value-of
     * or xsl:text element should be output without any escaping.
     * @see <a href="http://www.w3.org/TR/xslt#disable-output-escaping">disable-output-escaping in XSLT Specification</a>
     *
     * @param v The value to set for the "disable-output-escaping" attribute.
     */
    public void setDisableOutputEscaping(boolean v)
    {
      m_disableOutputEscaping = v;
    }
  
    /**
     * Get the "disable-output-escaping" attribute.
     * Normally, the xml output method escapes & and < (and
     * possibly other characters) when outputting text nodes.
     * This ensures that the output is well-formed XML. However,
     * it is sometimes convenient to be able to produce output
     * that is almost, but not quite well-formed XML; for
     * example, the output may include ill-formed sections
     * which are intended to be transformed into well-formed
     * XML by a subsequent non-XML aware process. For this reason,
     * XSLT provides a mechanism for disabling output escaping.
     * An xsl:value-of or xsl:text element may have a
     * disable-output-escaping attribute; the allowed values
     * are yes or no; the default is no; if the value is yes,
     * then a text node generated by instantiating the xsl:value-of
     * or xsl:text element should be output without any escaping.
     * @see <a href="http://www.w3.org/TR/xslt#disable-output-escaping">disable-output-escaping in XSLT Specification</a>
     *
     * @return The value of the "disable-output-escaping" attribute.
     */
    public boolean getDisableOutputEscaping()
    {
      return m_disableOutputEscaping;
    }
  
    /**
     * Get an integer representation of the element type.
     *
     * @return An integer representation of the element, defined in the
     *     Constants class.
     * @see org.apache.xalan.templates.Constants
     */
    public int getXSLToken()
    {
      return Constants.ELEMNAME_VALUEOF;
    }
  
    /**
     * This function is called after everything else has been
     * recomposed, and allows the template to set remaining
     * values that may be based on some other property that
     * depends on recomposition.
     *
     * NEEDSDOC @param sroot
     *
     * @throws TransformerException
     */
    public void compose(StylesheetRoot sroot) throws TransformerException
    {
  
      super.compose(sroot);
  
      java.util.Vector vnames = sroot.getComposeState().getVariableNames();
  
      if (null != m_selectExpression)
        m_selectExpression.fixupVariables(
          vnames, sroot.getComposeState().getGlobalsSize());
    }
  
    /**
     * Return the node name.
     *
     * @return The node name
     */
    public String getNodeName()
    {
      return Constants.ELEMNAME_VALUEOF_STRING;
    }
  
    /**
     * Execute the string expression and copy the text to the
     * result tree.
     * The required select attribute is an expression; this expression
     * is evaluated and the resulting object is converted to a string
     * as if by a call to the string function. The string specifies
     * the string-value of the created text node. If the string is
     * empty, no text node will be created. The created text node will
     * be merged with any adjacent text nodes.
     * @see <a href="http://www.w3.org/TR/xslt#value-of">value-of in XSLT Specification</a>
     *
     * @param transformer non-null reference to the the current transform-time state.
     *
     * @throws TransformerException
     */
    public void execute(TransformerImpl transformer) throws TransformerException
    {
  
      XPathContext xctxt = transformer.getXPathContext();
      SerializationHandler rth = transformer.getResultTreeHandler();
  
      if (transformer.getDebug())
        transformer.getTraceManager().fireTraceEvent(this);
  
      try
      {
        // Optimize for "."
        if (false && m_isDot && !transformer.getDebug())
        {
          int child = xctxt.getCurrentNode();
          DTM dtm = xctxt.getDTM(child);
  
          xctxt.pushCurrentNode(child);
  
          if (m_disableOutputEscaping)
            rth.processingInstruction(
              javax.xml.transform.Result.PI_DISABLE_OUTPUT_ESCAPING, "");
  
          try
          {
            dtm.dispatchCharactersEvents(child, rth, false);
          }
          finally
          {
            if (m_disableOutputEscaping)
              rth.processingInstruction(
                javax.xml.transform.Result.PI_ENABLE_OUTPUT_ESCAPING, "");
  
            xctxt.popCurrentNode();
          }
        }
        else
        {
          xctxt.pushNamespaceContext(this);
  
          int current = xctxt.getCurrentNode();
  
          xctxt.pushCurrentNodeAndExpression(current, current);
  
          if (m_disableOutputEscaping)
            rth.processingInstruction(
              javax.xml.transform.Result.PI_DISABLE_OUTPUT_ESCAPING, "");
  
          try
          {
            Expression expr = m_selectExpression.getExpression();
  
            if (transformer.getDebug())
            {
              XObject obj = expr.execute(xctxt);
  
              transformer.getTraceManager().fireSelectedEvent(current, this,
                      "select", m_selectExpression, obj);
              obj.dispatchCharactersEvents(rth);
            }
            else
            {
              expr.executeCharsToContentHandler(xctxt, rth);
            }
          }
          finally
          {
            if (m_disableOutputEscaping)
              rth.processingInstruction(
                javax.xml.transform.Result.PI_ENABLE_OUTPUT_ESCAPING, "");
  
            xctxt.popNamespaceContext();
            xctxt.popCurrentNodeAndExpression();
          }
        }
      }
      catch (SAXException se)
      {
        throw new TransformerException(se);
      }
      catch (RuntimeException re) {
      	TransformerException te = new TransformerException(re);
      	te.setLocator(this);
      	throw te;
      }
      finally
      {
        if (transformer.getDebug())
  	    transformer.getTraceManager().fireTraceEndEvent(this); 
      }
    }
  
    /**
     * Add a child to the child list.
     *
     * @param newChild Child to add to children list
     *
     * @return Child just added to children list
     *
     * @throws DOMException
     */
    public ElemTemplateElement appendChild(ElemTemplateElement newChild)
    {
  
      error(XSLTErrorResources.ER_CANNOT_ADD,
            new Object[]{ newChild.getNodeName(),
                          this.getNodeName() });  //"Can not add " +((ElemTemplateElement)newChild).m_elemName +
  
      //" to " + this.m_elemName);
      return null;
    }
    
    /**
     * Call the children visitors.
     * @param visitor The visitor whose appropriate method will be called.
     */
    protected void callChildVisitors(XSLTVisitor visitor, boolean callAttrs)
    {
    	if(callAttrs)
    		m_selectExpression.getExpression().callVisitors(m_selectExpression, visitor);
      super.callChildVisitors(visitor, callAttrs);
    }
  
  }
  