Java XPathContext.getVarStack方法代码示例

import org.apache.xpath.XPathContext; //导入方法依赖的package包/类
/**
 * Internal -- push the global variables from the Stylesheet onto
 * the context's runtime variable stack.
 * <p>If we encounter a variable
 * that is already defined in the variable stack, we ignore it.  This
 * is because the second variable definition will be at a lower import
 * precedence.  Presumably, global"variables at the same import precedence
 * with the same name will have been caught during the recompose process.
 * <p>However, if we encounter a parameter that is already defined in the
 * variable stack, we need to see if this is a parameter whose value was
 * supplied by a setParameter call.  If so, we need to "receive" the one
 * already in the stack, ignoring this one.  If it is just an earlier
 * xsl:param or xsl:variable definition, we ignore it using the same
 * reasoning as explained above for the variable.
 *
 * @param contextNode The root of the source tree, can't be null.
 *
 * @throws TransformerException
 */
protected void pushGlobalVars(int contextNode) throws TransformerException
{

  XPathContext xctxt = m_xcontext;
  VariableStack vs = xctxt.getVarStack();
  StylesheetRoot sr = getStylesheet();
  Vector vars = sr.getVariablesAndParamsComposed();
  
  int i = vars.size();
  vs.link(i);

  while (--i >= 0)
  {
    ElemVariable v = (ElemVariable) vars.elementAt(i);

    // XObject xobj = v.getValue(this, contextNode);
    XObject xobj = new XUnresolvedVariable(v, contextNode, this,
                                   vs.getStackFrame(), 0, true);
    
    if(null == vs.elementAt(i))                               
      vs.setGlobalVariable(i, xobj);
  }

}
 

import org.apache.xpath.XPathContext; //导入方法依赖的package包/类
/**
 * For support of literal objects in xpaths.
 *
 * @param xctxt The XPath execution context.
 *
 * @return This object.
 *
 * @throws javax.xml.transform.TransformerException
 */
public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
{
  if (!m_doneEval) 
  {
    this.m_transformer.getMsgMgr().error      
      (xctxt.getSAXLocator(), XSLTErrorResources.ER_REFERENCING_ITSELF, 
        new Object[]{((ElemVariable)this.object()).getName().getLocalName()}); 
  }
  VariableStack vars = xctxt.getVarStack();
  
  // These three statements need to be combined into one operation.
  int currentFrame = vars.getStackFrame();
  //// vars.setStackFrame(m_varStackPos);
 

  ElemVariable velem = (ElemVariable)m_obj;
  try
  {
    m_doneEval = false;
    if(-1 != velem.m_frameSize)
    	vars.link(velem.m_frameSize);
    XObject var = velem.getValue(m_transformer, m_context);
    m_doneEval = true;
    return var;
  }
  finally
  {
    // These two statements need to be combined into one operation.
    // vars.setStackFrame(currentFrame);
    
    if(-1 != velem.m_frameSize)
 	vars.unlink(currentFrame);
  }
}
 

import org.apache.xpath.XPathContext; //导入方法依赖的package包/类
public void execute(TransformerImpl transformer, XObject[] args)
        throws TransformerException
{
  XPathContext xctxt = transformer.getXPathContext();
  VariableStack vars = xctxt.getVarStack();
  
  // Increment the frame bottom of the variable stack by the
  // frame size
  int thisFrame = vars.getStackFrame();
  int nextFrame = vars.link(m_frameSize);

  if (m_inArgsSize < args.length) {
    throw new TransformerException ("function called with too many args");
  }
  
  // Set parameters,
  // have to clear the section of the stack frame that has params.
  if (m_inArgsSize > 0) {
    vars.clearLocalSlots(0, m_inArgsSize);

    if (args.length > 0) {
      vars.setStackFrame(thisFrame);
      NodeList children = this.getChildNodes();
      
      for (int i = 0; i < args.length; i ++) {
        Node child = children.item(i);
        if (children.item(i) instanceof ElemParam) {
          ElemParam param = (ElemParam)children.item(i);
          vars.setLocalVariable(param.getIndex(), args[i], nextFrame);
        }
      }
      
      vars.setStackFrame(nextFrame);
    }
  }

  //  Removed ElemTemplate 'push' and 'pop' of RTFContext, in order to avoid losing the RTF context 
  //  before a value can be returned. ElemExsltFunction operates in the scope of the template that called 
  //  the function.
  //  xctxt.pushRTFContext();
  
  vars.setStackFrame(nextFrame);
  transformer.executeChildTemplates(this, true);
  
  // Reset the stack frame after the function call
  vars.unlink(thisFrame);

  // Following ElemTemplate 'pop' removed -- see above.
  // xctxt.popRTFContext(); 
  
}
 

import org.apache.xpath.XPathContext; //导入方法依赖的package包/类
/**
 * Execute the expression.  Meant for reuse by other FilterExpr iterators 
 * that are not derived from this object.
 */
public static XNodeSet executeFilterExpr(int context, XPathContext xctxt, 
												PrefixResolver prefixResolver,
												boolean isTopLevel,
												int stackFrame,
												Expression expr )
  throws org.apache.xml.utils.WrappedRuntimeException
{
  PrefixResolver savedResolver = xctxt.getNamespaceContext();
  XNodeSet result = null;

  try
  {
    xctxt.pushCurrentNode(context);
    xctxt.setNamespaceContext(prefixResolver);

    // The setRoot operation can take place with a reset operation, 
    // and so we may not be in the context of LocPathIterator#nextNode, 
    // so we have to set up the variable context, execute the expression, 
    // and then restore the variable context.

    if (isTopLevel)
    {
      // System.out.println("calling m_expr.execute(getXPathContext())");
      VariableStack vars = xctxt.getVarStack();

      // These three statements need to be combined into one operation.
      int savedStart = vars.getStackFrame();
      vars.setStackFrame(stackFrame);

      result = (org.apache.xpath.objects.XNodeSet) expr.execute(xctxt);
      result.setShouldCacheNodes(true);

      // These two statements need to be combined into one operation.
      vars.setStackFrame(savedStart);
    }
    else
        result = (org.apache.xpath.objects.XNodeSet) expr.execute(xctxt);

  }
  catch (javax.xml.transform.TransformerException se)
  {

    // TODO: Fix...
    throw new org.apache.xml.utils.WrappedRuntimeException(se);
  }
  finally
  {
    xctxt.popCurrentNode();
    xctxt.setNamespaceContext(savedResolver);
  }
  return result;
}