Re: [patch] java.beans.EventHandler

[Bryce McKinlay <mckinlay at redhat dot com>]

Jerry Quinn wrote:

> Bryce McKinlay writes:
> > Hmm. It seems to me that you can infer propertyType by looking up the 
> > method for eventPropertyName and checking its return type? The return 
> > type for the event property must be compatible with the argument for the 
> > action, after all.
>
> Yes, but you don't yet know the class to look up eventPropertyName in when
> constructing the EventHandler.
The first argument to each listener method is the event. Is this not the 
class to look up eventPropertyName in?

>  Especially when directly calling the
> constructor.  Even when using the create methods, let's say you create without
> providing listenerMethodName.  This means that all listener methods are
> handled by using the first argument as the event.  Each one could potentially
> be passed a different object type.  Which do you use to acquire the Method
> object?
>  
If the listener has multiple listener methods, we can look up each one 
individually, although I think typically in a listener interface each 
method will have the same argument type, so for efficiency its probably 
best to remember past lookups and not repeat them again for multiple 
methods.

> > Even though the chain can be heirarchical, the objects in the chain at 
> > runtime must still be type compatible with the properties that were 
> > passed into the create() method, right?
>
> Except that the properties are passed as Strings and not Classes or Methods.
>  
I don't think this is a problem. Suppose eventPropertyName is "a.b.c". 
First we look up "a", take the class of that, lookup "b" in that class, 
etc... ?

Regards

Bryce