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

+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