Undertow is intended to be a lightweight web server rather than a container, so it does not really have any annotation processing facilities built in, however it should be fairly easy to implement something similar on top of Undertow.

Undertow has a handler called io.undertow.server.RoutingHandler, that routes requests based on method and path. If you use this handler it should be possible to build a handler chain based on annotations on the handler classes.

Note that you don't want to be using reflection in the handleRequest method, as reflection is relatively slow. Instead the best approach is to read the annotations and boot time and build up the routing map while the server is starting.

Stuart

Luke Ambrogio wrote:

So I've decided to start using Undertow, both as an experiment and due
to the great results it achieved in benchmark tests. And while I think
it's fantastic there's a feature which is either missing or I can't find.

I want to develop a RESTful web service so it's important for me to
identify which HTTP method is being called. Now I can get this from
RequestMethod in the HttpServerExchange parameter but if had to that for
every handler that would become tedious.

My solution, which works but feels wrong, is this:

Created an annotation interface called HTTPMethod:

|@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public  @interface  HTTPMethod  {

public  enum  Method  {

     OTHER,  GET,  PUT,  POST,  DELETE
}

Method  method()  default  Method.OTHER;|

an "abstract" class (which is not abstract):

|public  abstract  class  RESTfulHandler  implements  HttpHandler  {

@Override
public  void  handleRequest(HttpServerExchange  hse)  throws  Exception  {

     for  (Method  method:  this.getClass().getDeclaredMethods())  {

         // if method is annotated with @Test
         if  (method.isAnnotationPresent(HTTPMethod.class))  {

             Annotation  annotation=  method.getAnnotation(HTTPMethod.class);
             HTTPMethod  test=  (HTTPMethod)  annotation;

             switch  (test.method())  {
                 case  PUT:
                     if  (hse.getRequestMethod().toString().equals("PUT"))  {
                         method.invoke(this);
                     }
                     break;

                 case  POST:
                     if  (hse.getRequestMethod().toString().equals("POST"))  {
                         method.invoke(this);
                     }
                     break;

                 case  GET:
                     if  (hse.getRequestMethod().toString().equals("GET"))  {
                         method.invoke(this);
                     }
                     break;

                 case  DELETE:
                     if  (hse.getRequestMethod().toString().equals("DELETE"))  {
                         method.invoke(this);
                     }
                     break;
                 case  OTHER:
                     if  (hse.getRequestMethod().toString().equals("OTHER"))  {
                         method.invoke(this);
                     }
                     break;
             }
             if  (test.method()  ==  HTTPMethod.Method.PUT)  {
                 method.invoke(this);
             }
         }
     }
}|

}

and an implementation of both the above:

|public  class  ItemHandler  extends  RESTfulHandler{

@HTTPMethod(method=GET)
public  void  getAllItems()
{
     System.out.println("GET");
}

@HTTPMethod(method=POST)
public  void  addItem()
{
     System.out.println("POST");
}

@HTTPMethod
public  void  doNothing()
{
     System.out.println("OTHERS");
}|

}

Now as I said, it works, but I'm sure that the abstract class and it's
implementation have something missing so that they glue correctly. So my
question is two fold:

1) Is there a better / proper way to filter HTTP requests in Undertow?
2) What is the correct way of using annotations correctly correctly in
the above case?

Thanks

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