Throwing exception in event handler

ohaya Sat, 06 Oct 2007 08:26:45 -0700
Hi, 
 
I am working in a WebLogic/Workshop environment, and am VERY new to Beehive. 
 
I'm currently upgrading an application that was originally written in Workshop 
8.1 to WebLogic/Workshop 9.2.  This application uses several custom controls, 
and after upgrading by Workshop (via an import), the original custom controls 
got "converted" to Beehive controls. 
 
The original custom controls used what use to be the context_onAcquire() and 
context_onRelease() methods to setup the environment for the control code, and 
to cleanup the environment, respectively, and after the initial conversion, 
these two methods weren't being called. 
 
So, I manually added the necessary "things", e.g.: 
 
import org.apache.beehive.controls.api.events.EventHandler; 
import org.apache.beehive.controls.api.context.ResourceContext; 
. 
. 
    @org.apache.beehive.controls.api.context.Context 
    ResourceContext resourceContext; 
. 
. 
    @EventHandler(field="resourceContext", 
            eventSet=ResourceContext.ResourceEvents.class, 
            eventName="onAcquire") 
public void onAcquire() throws Exception 
{ 
.. code that use to be in context_onAcquire() 
} 
 
 
@EventHandler(field="resourceContext", 
            eventSet=ResourceContext.ResourceEvents.class, 
            eventName="onRelease") 
public void onRelease() throws Exception 
{ 
.. code that use to be in context_onRelease() 
} 
 
However, when I did that, and tried to build the application, I got an 
"Unhandled exception type Exception" in a module named 
"XXXImplInitializer.java": 
 
        public void onAcquire() 
        { 
            __bc_impl.onAcquire(); 
        } 
 
[In the original non-Beehive code, context_onAcquire() had: 
 
    public void context_onAcquire() throws Exception 
] 
 
I eventually worked around this problem by removing the "throws Exception" from 
the "public void onAcquire()" and by commenting out all of the "throw new 
Exception(...)" lines in the onAcquire() method. 
 
I think that info on the following page speaks to this under "Upgrading 
Exception Handling in Control Event Handlers": 
 
http://edocs.bea.com/workshop/docs92/ws_platform/upgrading/conUpgradingJavaContr
ols.html 
 
As I mentioned, I am really new to Beehive, but I think that my "workaround" is 
doing the 2nd option that page mentions, i.e.: 
 
"Remove the throws clause from the event handler code and implement another way 
to handle exceptions generated from the event" 
 
But, I'd like to reinstate things so that my controls do throw exceptions, but 
I'm not quite sure I understand how to implement the 1st option: 
 
"Add the throws clause your event handler is throwing to the EventSet event 
method. You will also need to add a corresponding try/catch block to code that 
invokes the event method" 
 
Is this just a matter of adding something to the "eventSet" in the 
"EventHandler" annotation, and also, if that is the case, can someone tell me 
exactly what I need to add there? 
 
Or, if I need to do something additional, what else do I need to do? 
 
Thanks in advance, 
Jim
Throwing exception in event handler

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