XPath parameter binding

[Arjen Poutsma]

Following my post, I tried to think of ways to make XPath easier. In Java, this is the way to evaluate an XPath expression.

XPathFactory factory = XPathFactory.newInstance();
XPath xpath = factory.newXPath();
XPathExpression expression =
xpath.compile("/Contacts/Contact/Name");
String result = expression.evaluate(document);

Clearly, this is too much plumbing to do each an every time. So I tried to make it easier, by using annotations. The end result looks something like this:

@Endpoint
public class MyEndpoint {
  
  @SoapAction("http://mycompany.com/soapAction")
  public void handleContact(
    @XpathParam("/Contacts/Contact/Name") String name) {
      // do something with name
  }
 
}

The idea is to tag any object with @Endpoint, tag methods with @SoapAction to indicate that handleContact should be called for incoming messages with the "http://mycompany.com/soapAction" SOAPAction header. The parameters are bound to the result of the XPath expression. Besides String, other supported parameters types are boolean, double, Node, and NodeList (the supported types by XPath):

    public void supportedTypes(@XPathParam("/root/child")boolean param1,
                               @XPathParam("/root/child/number")double param2,
                               @XPathParam("/root/child")Node param3,
                               @XPathParam("/root/*")NodeList param4,
                               @XPathParam("/root/child/text")String param5) {

This programming model is a Java 5 alternative for PayloadEndpoint and MethodEndpoint (and it's subclasses). Besides using @XPathParam, you can also use a Marshaller:

    @SoapAction("http://mycompany.com/soapAction")
    public MarshalledType response(UnmarshalledType type) {
        ...
    }

This has not been submitted to SVN yet, because it requires a little more work. However, I would love to hear from your opinions on this feature. I like it, but I'm open for other or better thoughts .

[Arjen Poutsma]

I would really appreciate some feedback on this . If think I will push it into 1.0, if enough people like it.