public boolean evaluate(Node contextNode,Node xpathnode,String str,Node namespaceNode) throws TransformerException {
  XObject object=eval(contextNode,xpathnode,str,namespaceNode);
  return object.bool();
}

public boolean evaluate ( Node contextNode , Node xpathnode , String str , Node namespaceNode ) throws TransformerException { XObject object = eval ( contextNode , xpathnode , str , namespaceNode ) ; return object . bool ( ) ; }
evaluate an xpath string and return true if the output is to be included or not .
