On Wed, 13 Aug 2003, Joe Germuska wrote: > Date: Wed, 13 Aug 2003 22:01:30 -0500 > From: Joe Germuska <[EMAIL PROTECTED]> > Reply-To: Struts Developers List <[EMAIL PROTECTED]> > To: Struts Developers List <[EMAIL PROTECTED]> > Subject: RE: ActionForwards, et al (was SuccessAction) > > At 9:07 PM -0400 8/12/03, Byrne, Steven wrote: > >I guess I have to reiterate what others have said earlier today: how do > >you deal with handling or enforcing composition order? I.e. are you > >implicitly assuming/requiring that the various elements in the chain are > >orthogonal with respect to changes in the input/output "stream" or > >changes in state that other elements in the chain might have visibility > >into? Or do you assume that the composition order is part of the > >interface specification, document accordingly, and hope that your > >clients will read and follow the ordering specification? > > Ted H more or less suggested this, but I think the way to go is to > give each command an opportunity to validate any contract > pre-conditions, like expecting certain beans to be defined in the > context. You could even just leave this up to the command author to > do in the main execute method, but it might promote good practice if > it were explicitly in the API. >
How would you suggest putting something like this into the API? Adding a method like verifyPreconditions() seems like it makes things harder instead of easier -- why not just let the execute() method throw an IllegalStateException (or something like that) if its preconditions are not met? Such a policy is easily unit testable as well. > Joe Craig --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
