Re: Xpath API takes longer in 2.2.D9 as compared to 2.0.1

[Scott_Boag]

I suspect this is the cost of building the DTM adapter to the DOM.  If the
slowdown is critical, then it may be better to pre-build a DOM2DTM, and use
the lower-level XPath APIs.

-scott




                                                                                       
                            
                    "Nathan                                                            
                            
                    Krishnan"            To:     <[EMAIL PROTECTED]>            
                            
                    <nathan@nextan       cc:     (bcc: Scott Boag/CAM/Lotus)           
                            
                    ce.com>              Subject:     Xpath API takes longer in 2.2.D9 
as compared to 2.0.1        
                                                                                       
                            
                    08/23/2001                                                         
                            
                    05:15 PM                                                           
                            
                    Please respond                                                     
                            
                    to xalan-dev                                                       
                            
                                                                                       
                            
                                                                                       
                            




Hi,

We use Xpath API's to access text and attribute values based on xpath
expressions.

It used to run very quickly (0-10 msec for each eval) in Xalan 2.0.1. But
in
2.2 it takes much longer (150-200 msec for each eval). The timing gets
progressively worse as the depth of the tree increases.

Here is the sample XML result coming from a database query which is being
parsed. There are about 200 message nodes. I have included only a couple of
message
nodes here for brevity. Should we be using lower level Xpath api's ?

Thanks

Nathan

<?xml version="1.0" encoding="UTF-8"?>
<result xmlns:ino="http://namespaces.softwareag.com/tamino/response2";>
           <messagecatalog docType="messagecatalog" ino:id="1" lang="en"
objectId="1">
                     <message code="000001">
                               <type>error</type>
                               <text>Agreement ID Node Does Not
Exist.</text>
                               <category>system</category>
                               <severity>30</severity>
                     </message>
                     <message code="000002">
                               <type>error</type>
                               <text>No Agreement ID entered. Please enter
Agreement ID.</text>
                               <category>system</category>
                               <severity>30</severity>
                     </message>
   </messagacatalog>
</result>

Here is the code that parses each message node passed to it as the context
node.

/**
     * Gets the value from a node using XPath expression.
     * @param contextNode   <code>Node</code> to be searched for the value
     * @param xpath         query path to the node that has the value
     * @return  value of the node pointed to by the xpath expression.
     */
    public static String getValue(Node contextNode, String xpath) {
        if (contextNode == null) {
            return null;
        }

        String value = null;

        try {
            long begin = System.currentTimeMillis();

            Node node = XPathAPI.selectSingleNode(contextNode,xpath);

            System.out.println("time=" +
(System.currentTimeMillis()-begin));

            if (node != null) {
                switch (node.getNodeType()) {
                    case Node.TEXT_NODE :
                        value = node.getNodeValue();
                        break;

                    case Node.ATTRIBUTE_NODE :
                        value = ((Attr)node).getValue();
                        break;

                    case Node.ELEMENT_NODE :
                        NodeList childNodes = node.getChildNodes();
                        for (int i = 0; i < childNodes.getLength(); i++) {
                            Node child = childNodes.item(i);
                            if (child != null && child.getNodeType() ==
Node.TEXT_NODE) {
                                value = child.getNodeValue();
                                break;
                            }
                        }
                        break;
                }
            }
        } catch(TransformerException te) {
        }

        if (value != null) {
            value = value.trim();
            if (value.length() == 0) {
                value = null;
            }
        }

        return value;

    }