[jsr-314-open] Method signatures for event handlers

[Cagatay Civici]

+1 as well, most of the time it's a burden to add the unused event parameter.

Cagatay

On Jan 22, 2010, at 8:08 PM, Jason Lee wrote:

> +1
> 
> I'd wager that half the time I don't need the parameter I'm required to pass in, so I'd love to this made optional.  Officially.
> 
> On 1/22/10 1:57 PM, Andy Schwartz wrote:
>> Cay Horstmann wrote:
>>> On 01/22/2010 08:52 AM, Kito Mann wrote:
>>>> Personally, I don't think there's anything wrong with having a signature
>>>> that requires an event listener. Isn't that how most UI toolkits work?
>>>> What about Swing or SWT?
>>>> 
>>>> I do understand the desire to have some code completely decoupled,
>>>> though. If we make the signature optional, though, I'm afraid that'll be
>>>> even more confusing for users.
>>> 
>>> I don't think it is confusing to say "This parameter is optional". Lots of things are optional in JSF.
>> 
>> Yep.  Actually, for the nearest equivalent to this use case - h:commandButton's actionListener - we have specified that the ActionEvent is now optional (as of 2.0 I believe).  From the tag doc:
>> 
>> 
>>> The expression must evaluate to a public method that takes an ActionEvent parameter, with a return type of void, or to a public method that takes no arguments with a return type of void. In the latter case, the method has no way of easily knowing where the event came from, but this can be useful in cases where a notification is needed that "some action happened".
>> 
>> 
>> Given that, my take is that:
>> 
>> 1. Our biggest risk of confusion would be to have the the spec be inconsistent between these cases.
>> 2. The behavior specified for actionListener (event parameter is optional) is the preferred behavior.  (We intentionally added this behavior in 2.0).
>> 3. The fact that Mojarra implements this behavior for f:event's listener attribute as well is a good thing (and probably intentional).
>> 4. We should update the spec in our upcoming MR to clarify that the current behavior is by design.
>> 
>> I have logged the following spec issue to track this:
>> 
>> https://javaserverfaces-spec-public.dev.java.net/issues/show_bug.cgi?id=731 
>> 
>> Andy
>> 
>>> The reason you want to make it so is to have a better unit testing story.
>>> 
>>> Cay
>>> 
>> 
> 
> 
> -- 
> Jason Lee, SCJP
> President, Oklahoma City Java Users Group
> Senior Java Developer, Sun Microsystems
> http://blogs.steeplesoft.com
>