I've asked recently about dealing with Threads in Swing.  Now I have one
other problem and I THINK the term I want is a callback, but it's hard to
find docs on this.  Basically I have a primary Swing thread that has
invoked a subthread to process data while the display refreshes.

The 2nd thread is created with an entire external class (for many reasons).
When the 2nd thread finishes, I want it to be able to call the first class
back and update some data and tell it to display a message window.  I know
I can use invokeLater() for the message window, and that way it'll be
handled by the main Swing thread, but there are several questions I have
about trying to set data in the calling class.

Is there a way to set up a listener in the calling class that the subthread
and class the subthread is in can trigger it?

I found I could not pass the class itself as a class, but had to pass it as
an object, then, inside the object, I can use Object.getClass() to get the
class, but that I can't cast the Object to class or get an actual instance
of the calling class.  I can find a method, and then, from inside the
subthread class, call the method in the original calling class, but it
needs a new instance of the class, which, unless I am completely wrong,
will not contain the same data as the calling class -- it'll be a whole new
instance of it.  Is there a way for a class to pass an instance of itself
as a parameter and for the called class to actually get that instance?

Is there a standard way to put a listener in a class and have another class
trigger an event of some kind or an exception that forces the first class
to handle it?

Thanks for any help!

Hal