This is the 3rd version of SwingWorker (also known as
SwingWorker 3), an abstract class that you subclass to
perform GUI-related work in a dedicated thread. For
instructions on using this class, see:
Note that the API changed slightly in the 3rd version:
You must now invoke start() on the SwingWorker after
Start a thread that will call the construct method
and then exit.
Compute the value to be returned by the get method.
Called on the event dispatching thread (not on the worker thread)
after the construct method has returned.
Return the value created by the construct method.
Get the value produced by the worker thread, or null if it
hasn't been constructed yet.
A new method that interrupts the worker thread.