Question

Are there any good tools or techniques to profile Wicket applications? What I’m looking for is something that would give me a breakdown of what’s happening inside Wicket while processing a request.

It doesn’t have to be as fancy as Spring insight.

I’m new to Wicket and all the anonymous inner classes spread around everywhere makes it very hard to see when things are happening.

Answer 1

At least for Wicket 1.4 one can take a look at the internal method org.apache.wicket.RequestCycle.steps(). Basically, this is the place where a request that has been identified as a request to the Wicket application is walked through the relevant steps of the Wicket request processing cycle. In the beginning of the class RequestCycle, the main steps are represented each by an int constant. The higher the int value, the later the step comes within the cycle. The method RequestCycle.step() that gets called from RequestCycle.steps() has a switch statement to delegate the different steps to the responsible framework methods which delegate further down.

The steps, or phases if you like, in the request cycle are in order:

• NOT_STARTED – initial value
• PREPARE_REQUEST – preparation for further processing, calls onBeginRequest
• RESOLVE_TARGET – determine the relevant request target
• PROCESS_EVENTS – process events, set current step to RESPOND and respond as well
• RESPOND – only respond, used in case of redirects
• DETACH_REQUEST – trigger the detach hooks by delegation
• DONE – becomes the current value after DETACH_REQUEST

What is actually happening inside the steps is determined by the implementations of various interfaces, most notably IRequestCycleProcessor and IRequestTarget.