Re: [patch] java.beans.EventHandler

[Bryce McKinlay <mckinlay at redhat dot com>]

Jerry Quinn wrote:

> > >+    // Find the actual method of target to invoke.  We can't do this in the
> > >+    // constructor since we don't know the type of the property we extracted
> > >+    // from the event then.
> > >+    //
> > >+    // action can be either a property or a method.  Sun's docs seem to imply
> > >+    // that action should be treated as a property first, and then a method,
> > >+    // but don't specifically say it.
> > >+    //
> > >+    // XXX check what happens with native type wrappers.  The better thing to
> > >+    // do is look at the return type of the method
> > >+    Method actionMethod;
> > >+    try
> > >+      {
> > >+       // Look for a property setter for action.
> > >+       actionMethod =
> > >+         target.getClass().getMethod("set" + capitalize(action),
> > >+                                     new Class[] {propertyType});
> > >+      }
> > >  
> > >
> > 
> > It would be much faster to look up the actionMethod once when the 
> > EventHandler is constructed, and cache it, rather than looking it up 
> > again during every dispatch. Looking up methods can be quite slow, plus 
> > you'll avoid several allocations.
>
> I started to do that.  The problem is that you don't know propertyType when
> the EventHandler is constructed, because you don't know the object that the
> event will be pulled from.  Also, the property is hierarchical, which means
> walking down a chain of objects to find this property and this chain could be
> assembled at run time.
>  
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.

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?

Regards

Bryce