[groovy-user] Hooks and Callbacks

Hi all,

I'm looking for a recommendation on how to best implement hooks and 
callbacks in groovy.  The basic pattern includes the following:

1. Hooks are keys against which callbacks (closures) can be registered.  
A map is associated with this registration that contains information 
that can be used when callbacks against a hook is executed.

2. In code, callbacks for a given hook can be executed.  Arguments can 
be passed to the hook.execute() call that, in conjunction with the map 
that is associated with callbacks, determines the order in which 
callbacks are executed or even whether a given callback is executed or not.

3. The above is not an event-driven pattern.  It just allows for code 
logic to be more extensible and allows for template-based code design 
where basic functionality can be provided by the template designer and 
augmented by the template user by registering additional callbacks 
against known hooks.

I've fully implemented this in C++ code, but I'm now looking to take 
advantage of whatever Groovy might provide to make this easier.

Any thoughts?

Thanks,
Steve Amerige
SAS Institute, Deployment Developer

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