http://xml.apache.org/xalan-j/: Xalan-Java is an XSLT processor for transforming XML documents into HTML, text, or other XML document types. It implements XSL Transformations (XSLT) Version 1.0 and XML Path Language (XPath) Version 1.0 and can be used from the command line, in an applet or a servlet, or as a module in other program. (The Apache Software Foundation) 
/*
 * 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: ElemVariable.java 468643 2006-10-28 06:56:03Z minchau $
 */
package org.apache.xalan.templates;

import javax.xml.transform.TransformerException;

import org.apache.xalan.transformer.TransformerImpl;
import org.apache.xml.utils.QName;
import org.apache.xpath.XPath;
import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.objects.XRTreeFrag;
import org.apache.xpath.objects.XRTreeFragSelectWrapper;
import org.apache.xpath.objects.XString;
import org.apache.xalan.res.XSLTErrorResources;


Implement xsl:variable.






See Also:
@xsl.usageadvanced
/**
 * Implement xsl:variable.
 * <pre>
 * <!ELEMENT xsl:variable %template;>
 * <!ATTLIST xsl:variable
 *   name %qname; #REQUIRED
 *   select %expr; #IMPLIED
 * >
 * </pre>
 * @see <a href="http://www.w3.org/TR/xslt#variables">variables in XSLT Specification</a>
 * @xsl.usage advanced
 */
public class ElemVariable extends ElemTemplateElement
{
    static final long serialVersionUID = 9111131075322790061L;

  
Constructor ElemVariable

/**
   * Constructor ElemVariable
   *
   */
  public ElemVariable(){}

  
This is the index into the stack frame.

/**
   * This is the index into the stack frame.
   */
  protected int m_index;
  
  
The stack frame size for this variable if it is a global variable 
that declares an RTF, which is equal to the maximum number 
of variables that can be declared in the variable at one time.

/**
   * The stack frame size for this variable if it is a global variable 
   * that declares an RTF, which is equal to the maximum number 
   * of variables that can be declared in the variable at one time.
   */
  int m_frameSize = -1;

  
  
Sets the relative position of this variable within the stack frame (if local)
or the global area (if global).  Note that this should be called only for
global variables since the local position is computed in the compose() method.

/**
   * Sets the relative position of this variable within the stack frame (if local)
   * or the global area (if global).  Note that this should be called only for
   * global variables since the local position is computed in the compose() method.
   */
  public void setIndex(int index)
  {
    m_index = index;
  }

  
If this element is not at the top-level, get the relative position of the
variable into the stack frame.  If this variable is at the top-level, get
the relative position within the global area.

/**
   * If this element is not at the top-level, get the relative position of the
   * variable into the stack frame.  If this variable is at the top-level, get
   * the relative position within the global area.
   */
  public int getIndex()
  {
    return m_index;
  }

  
The value of the "select" attribute.

@serial
/**
   * The value of the "select" attribute.
   * @serial

   */
  private XPath m_selectPattern;

  
Set the "select" attribute.
If the variable-binding element has a select attribute,
then the value of the attribute must be an expression and
the value of the variable is the object that results from
evaluating the expression. In this case, the content
of the variable must be empty.

Params:
  • v – Value to set for the "select" attribute.
/**
   * Set the "select" attribute.
   * If the variable-binding element has a select attribute,
   * then the value of the attribute must be an expression and
   * the value of the variable is the object that results from
   * evaluating the expression. In this case, the content
   * of the variable must be empty.
   *
   * @param v Value to set for the "select" attribute.
   */
  public void setSelect(XPath v)
  {
    m_selectPattern = v;
  }

  
Get the "select" attribute.
If the variable-binding element has a select attribute,
then the value of the attribute must be an expression and
the value of the variable is the object that results from
evaluating the expression. In this case, the content
of the variable must be empty.

Returns:Value of the "select" attribute.
/**
   * Get the "select" attribute.
   * If the variable-binding element has a select attribute,
   * then the value of the attribute must be an expression and
   * the value of the variable is the object that results from
   * evaluating the expression. In this case, the content
   * of the variable must be empty.
   *
   * @return Value of the "select" attribute.
   */
  public XPath getSelect()
  {
    return m_selectPattern;
  }

  
The value of the "name" attribute.

@serial
/**
   * The value of the "name" attribute.
   * @serial

   */
  protected QName m_qname;

  
Set the "name" attribute.
Both xsl:variable and xsl:param have a required name
attribute, which specifies the name of the variable. The
value of the name attribute is a QName, which is expanded
as described in [2.4 Qualified Names].

Params:
  • v – Value to set for the "name" attribute.
See Also:
/**
   * Set the "name" attribute.
   * Both xsl:variable and xsl:param have a required name
   * attribute, which specifies the name of the variable. The
   * value of the name attribute is a QName, which is expanded
   * as described in [2.4 Qualified Names].
   * @see <a href="http://www.w3.org/TR/xslt#qname">qname in XSLT Specification</a>
   *
   * @param v Value to set for the "name" attribute.
   */
  public void setName(QName v)
  {
    m_qname = v;
  }

  
Get the "name" attribute.
Both xsl:variable and xsl:param have a required name
attribute, which specifies the name of the variable. The
value of the name attribute is a QName, which is expanded
as described in [2.4 Qualified Names].

See Also:
Returns:Value of the "name" attribute.
/**
   * Get the "name" attribute.
   * Both xsl:variable and xsl:param have a required name
   * attribute, which specifies the name of the variable. The
   * value of the name attribute is a QName, which is expanded
   * as described in [2.4 Qualified Names].
   * @see <a href="http://www.w3.org/TR/xslt#qname">qname in XSLT Specification</a>
   *
   * @return Value of the "name" attribute.
   */
  public QName getName()
  {
    return m_qname;
  }

  
Tells if this is a top-level variable or param, or not.

@serial
/**
   * Tells if this is a top-level variable or param, or not.
   * @serial

   */
  private boolean m_isTopLevel = false;

  
Set if this is a top-level variable or param, or not.

Params:
  • v – Boolean indicating whether this is a top-level variable
or param, or not.
See Also:
/**
   * Set if this is a top-level variable or param, or not.
   * @see <a href="http://www.w3.org/TR/xslt#top-level-variables">top-level-variables in XSLT Specification</a>
   *
   * @param v Boolean indicating whether this is a top-level variable
   * or param, or not.
   */
  public void setIsTopLevel(boolean v)
  {
    m_isTopLevel = v;
  }

  
Get if this is a top-level variable or param, or not.

See Also:
Returns:Boolean indicating whether this is a top-level variable
or param, or not.
/**
   * Get if this is a top-level variable or param, or not.
   * @see <a href="http://www.w3.org/TR/xslt#top-level-variables">top-level-variables in XSLT Specification</a>
   *
   * @return Boolean indicating whether this is a top-level variable
   * or param, or not.
   */
  public boolean getIsTopLevel()
  {
    return m_isTopLevel;
  }

  
Get an integer representation of the element type.

See Also:
Returns:An integer representation of the element, defined in the
    Constants class.
/**
   * 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_VARIABLE;
  }

  
Return the node name.

Returns:The node name
/**
   * Return the node name.
   *
   * @return The node name
   */
  public String getNodeName()
  {
    return Constants.ELEMNAME_VARIABLE_STRING;
  }

  
Copy constructor.

Params:
  • param – An element created from an xsl:variable
Throws:
/**
   * Copy constructor.
   *
   * @param param An element created from an xsl:variable
   *
   * @throws TransformerException
   */
  public ElemVariable(ElemVariable param) throws TransformerException
  {

    m_selectPattern = param.m_selectPattern;
    m_qname = param.m_qname;
    m_isTopLevel = param.m_isTopLevel;

    // m_value = param.m_value;
    // m_varContext = param.m_varContext;
  }

  
Execute a variable declaration and push it onto the variable stack.

Params:
  • transformer – non-null reference to the the current transform-time state.
Throws:
See Also:
/**
   * Execute a variable declaration and push it onto the variable stack.
   * @see <a href="http://www.w3.org/TR/xslt#variables">variables 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
  {

    if (transformer.getDebug())
      transformer.getTraceManager().fireTraceEvent(this);

    int sourceNode = transformer.getXPathContext().getCurrentNode();
  
    XObject var = getValue(transformer, sourceNode);

    // transformer.getXPathContext().getVarStack().pushVariable(m_qname, var);
    transformer.getXPathContext().getVarStack().setLocalVariable(m_index, var);
    
    if (transformer.getDebug())
	  transformer.getTraceManager().fireTraceEndEvent(this);         
  }

  
Get the XObject representation of the variable.

Params:
  • transformer – non-null reference to the the current transform-time state.
  • sourceNode – non-null reference to the current source node.
Throws:
Returns:the XObject representation of the variable.
/**
   * Get the XObject representation of the variable.
   *
   * @param transformer non-null reference to the the current transform-time state.
   * @param sourceNode non-null reference to the <a href="http://www.w3.org/TR/xslt#dt-current-node">current source node</a>.
   *
   * @return the XObject representation of the variable.
   *
   * @throws TransformerException
   */
  public XObject getValue(TransformerImpl transformer, int sourceNode)
          throws TransformerException
  {

    XObject var;
    XPathContext xctxt = transformer.getXPathContext();

    xctxt.pushCurrentNode(sourceNode);
 
    try
    {
      if (null != m_selectPattern)
      {
        var = m_selectPattern.execute(xctxt, sourceNode, this);

        var.allowDetachToRelease(false);

        if (transformer.getDebug())
          transformer.getTraceManager().fireSelectedEvent(sourceNode, this,
                  "select", m_selectPattern, var);
      }
      else if (null == getFirstChildElem())
      {
        var = XString.EMPTYSTRING;
      }
      else
      {

        // Use result tree fragment.
        // Global variables may be deferred (see XUnresolvedVariable) and hence
        // need to be assigned to a different set of DTMs than local variables
        // so they aren't popped off the stack on return from a template.
        int df;

		// Bugzilla 7118: A variable set via an RTF may create local
		// variables during that computation. To keep them from overwriting
		// variables at this level, push a new variable stack.
		////// PROBLEM: This is provoking a variable-used-before-set
		////// problem in parameters. Needs more study.
		try
		{
			//////////xctxt.getVarStack().link(0);
			if(m_parentNode instanceof Stylesheet) // Global variable
				df = transformer.transformToGlobalRTF(this);
			else
				df = transformer.transformToRTF(this);
    	}
		finally{ 
			//////////////xctxt.getVarStack().unlink(); 
			}

        var = new XRTreeFrag(df, xctxt, this);
      }
    }
    finally
    {      
      xctxt.popCurrentNode();
    }

    return var;
  }
  
  
  
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.

/**
   * 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.
   */
  public void compose(StylesheetRoot sroot) throws TransformerException
  {
    // See if we can reduce an RTF to a select with a string expression.
    if(null == m_selectPattern  
       && sroot.getOptimizer())
    {
      XPath newSelect = rewriteChildToExpression(this);
      if(null != newSelect)
        m_selectPattern = newSelect;
    }
    
    StylesheetRoot.ComposeState cstate = sroot.getComposeState();
    
    // This should be done before addVariableName, so we don't have visibility 
    // to the variable now being defined.
    java.util.Vector vnames = cstate.getVariableNames();
    if(null != m_selectPattern)
      m_selectPattern.fixupVariables(vnames, cstate.getGlobalsSize());
      
    // Only add the variable if this is not a global.  If it is a global, 
    // it was already added by stylesheet root.
    if(!(m_parentNode instanceof Stylesheet) && m_qname != null)
    {
      m_index = cstate.addVariableName(m_qname) - cstate.getGlobalsSize();
    }
    else if (m_parentNode instanceof Stylesheet)
    {
    	// If this is a global, then we need to treat it as if it's a xsl:template, 
    	// and count the number of variables it contains.  So we set the count to 
    	// zero here.
		cstate.resetStackFrameSize();
    }
    
    // This has to be done after the addVariableName, so that the variable 
    // pushed won't be immediately popped again in endCompose.
    super.compose(sroot);
  }
  
  
This after the template's children have been composed.  We have to get 
the count of how many variables have been declared, so we can do a link 
and unlink.

/**
   * This after the template's children have been composed.  We have to get 
   * the count of how many variables have been declared, so we can do a link 
   * and unlink.
   */
  public void endCompose(StylesheetRoot sroot) throws TransformerException
  {
    super.endCompose(sroot);
    if(m_parentNode instanceof Stylesheet)
    {
    	StylesheetRoot.ComposeState cstate = sroot.getComposeState();
    	m_frameSize = cstate.getFrameSize();
    	cstate.resetStackFrameSize();
    }
  }

  
  
//  /**
//   * This after the template's children have been composed.
//   */
//  public void endCompose() throws TransformerException
//  {
//    super.endCompose();
//  }


  
If the children of a variable is a single xsl:value-of or text literal, 
it is cheaper to evaluate this as an expression, so try and adapt the 
child an an expression.

Params:
  • varElem – Should be a ElemParam, ElemVariable, or ElemWithParam.
Throws:
Returns:An XPath if rewrite is possible, else null.
/**
   * If the children of a variable is a single xsl:value-of or text literal, 
   * it is cheaper to evaluate this as an expression, so try and adapt the 
   * child an an expression.
   *
   * @param varElem Should be a ElemParam, ElemVariable, or ElemWithParam.
   *
   * @return An XPath if rewrite is possible, else null.
   *
   * @throws TransformerException
   */
  static XPath rewriteChildToExpression(ElemTemplateElement varElem)
          throws TransformerException
  {

    ElemTemplateElement t = varElem.getFirstChildElem();

    // Down the line this can be done with multiple string objects using 
    // the concat function.
    if (null != t && null == t.getNextSiblingElem())
    {
      int etype = t.getXSLToken();

      if (Constants.ELEMNAME_VALUEOF == etype)
      {
        ElemValueOf valueof = (ElemValueOf) t;

        // %TBD% I'm worried about extended attributes here.
        if (valueof.getDisableOutputEscaping() == false
                && valueof.getDOMBackPointer() == null)
        {
          varElem.m_firstChild = null;

          return new XPath(new XRTreeFragSelectWrapper(valueof.getSelect().getExpression()));
        }
      }
      else if (Constants.ELEMNAME_TEXTLITERALRESULT == etype)
      {
        ElemTextLiteral lit = (ElemTextLiteral) t;

        if (lit.getDisableOutputEscaping() == false
                && lit.getDOMBackPointer() == null)
        {
          String str = lit.getNodeValue();
          XString xstr = new XString(str);

          varElem.m_firstChild = null;

          return new XPath(new XRTreeFragSelectWrapper(xstr));
        }
      }
    }

    return null;
  }

  
This function is called during recomposition to
control how this element is composed.

Params:
  • root – The root stylesheet for this transformation.
/**
   * This function is called during recomposition to
   * control how this element is composed.
   * @param root The root stylesheet for this transformation.
   */
  public void recompose(StylesheetRoot root)
  {
    root.recomposeVariables(this);
  }
  
  
Set the parent as an ElemTemplateElement.

Params:
  • p – This node's parent as an ElemTemplateElement
/**
   * Set the parent as an ElemTemplateElement.
   *
   * @param p This node's parent as an ElemTemplateElement
   */
  public void setParentElem(ElemTemplateElement p)
  {
    super.setParentElem(p);
    p.m_hasVariableDecl = true;
  }
  
  
Accept a visitor and call the appropriate method 
for this class.

Params:
  • visitor – The visitor whose appropriate method will be called.
Returns:true if the children of the object should be visited.
/**
   * Accept a visitor and call the appropriate method 
   * for this class.
   * 
   * @param visitor The visitor whose appropriate method will be called.
   * @return true if the children of the object should be visited.
   */
  protected boolean accept(XSLTVisitor visitor)
  {
  	return visitor.visitVariableOrParamDecl(this);
  }

  
  
Call the children visitors.

Params:
  • visitor – The visitor whose appropriate method will be called.
/**
   * Call the children visitors.
   * @param visitor The visitor whose appropriate method will be called.
   */
  protected void callChildVisitors(XSLTVisitor visitor, boolean callAttrs)
  {
  	if(null != m_selectPattern)
  		m_selectPattern.getExpression().callVisitors(m_selectPattern, visitor);
    super.callChildVisitors(visitor, callAttrs);
  }
  
  
Tell if this is a psuedo variable reference, declared by Xalan instead 
of by the user.

/**
   * Tell if this is a psuedo variable reference, declared by Xalan instead 
   * of by the user.
   */
  public boolean isPsuedoVar()
  {
  	java.lang.String ns = m_qname.getNamespaceURI();
  	if((null != ns) && ns.equals(RedundentExprEliminator.PSUEDOVARNAMESPACE))
  	{
  		if(m_qname.getLocalName().startsWith("#"))
  			return true;
  	}
  	return false;
  }
  
  
Add a child to the child list. If the select attribute
is present, an error will be raised.

Params:
  • elem – New element to append to this element's children list
Returns:null if the select attribute was present, otherwise the 
child just added to the child list
/**
   * Add a child to the child list. If the select attribute
   * is present, an error will be raised.
   *
   * @param elem New element to append to this element's children list
   *
   * @return null if the select attribute was present, otherwise the 
   * child just added to the child list 
   */
  public ElemTemplateElement appendChild(ElemTemplateElement elem)
  {
    // cannot have content and select
    if (m_selectPattern != null)
    {
      error(XSLTErrorResources.ER_CANT_HAVE_CONTENT_AND_SELECT, 
          new Object[]{"xsl:" + this.getNodeName()});
      return null;
    }
    return super.appendChild(elem);
  }

}