Re: [Actionframework-users] ANNOUNCE: ActionServlet 0.93.2c

[Petr T. <Pet...@pi...>]

 >> - bugfix: Velocity's error() was not overridden to call
 >> ActionServlet.error()
 >
 > Thanks; unfortunately (and I should have caught this before) I still
 > can't do transaction management. That is because cleanupRequest() is
 > private, and doesn't pass in Context anyway. There is afterInvoke(),
 > but it still happens before template merging. And velocity's
 > requestCleanup() is not hooked by AS. Lastly, I can't deal with this
 > by overriding doGet and doPost, because the superclass calls its
 > cleanup which will invalidate my request-level components before I
 > can do my own cleanup.
 >
 > So I don't see any way for request cleanup.

VelocityServlet (combining AS + Velocity) method calls are:

"HTTP request" -> doGet()/doPost() -> doRequest(...)

protected void doRequest(...) {
    try {
        handleRequest(request, response, context)
           -> ActionServlet.handle(...)

        if (template != null) {
            mergeTemplate(template, context, response);
            requestCleanup(request, response, context);
        }
    } catch (Exception e) {
        error(request, response, e)
           -> ActionServlet.error(...);
    }
}

Conclusion from this schema: if ActionServlet.error() is not called
during the request, everything  is ok. Therefore, you can override
doGet(), doPost() and error() in your servlet like this:

private Hashtable data = new Hashtable();

protected void doGet(HttpServletRequest req, HttpServletResponse res) {
     super.doGet(req, res);
     finishTransaction();
}

protected void doPost(HttpServletRequest req, HttpServletResponse res) {
     super.doPost(req, res);
     finishTransaction();
}

public Template error(Context context, String message, Throwable e) {
     // get unique id for current thread (i.e. request)
     Integer threadId =
         new Integer(System.identityHashCode(Thread.currentThread()));

     // save context (or set error flag - whatever you need)
     data.put(threadId, context);

     super.error(context, message, e);
}

private void finishTransaction() {
     Integer threadId =
         new Integer(System.identityHashCode(Thread.currentThread()));

     // check for error
     if (data.contains(threadId)) {
         // rollback transaction

         data.remove(threadId);
     } else {
         // commit transaction
     }
}

But I think that adding ActionServlet.requestCleanup(Context ctx) is not
a bad idea - for AS 0.94 :)

Petr
-- 
[ http://dione.zcu.cz/~toman40 - Pet...@pi... - ICQ=22957959 ]