The listener interface for receiving component events.
The class that is interested in processing a component event
either implements this interface (and all the methods it
contains) or extends the abstract
ComponentAdapter
class
(overriding only the methods of interest).
The listener object created from that class is then registered with a
component using the component's
addComponentListener
method. When the component's size, location, or visibility
changes, the relevant method in the listener object is invoked,
and the
ComponentEvent
is passed to it.
Component events are provided for notification purposes ONLY;
The AWT will automatically handle component moves and resizes
internally so that GUI layout works properly regardless of
whether a program registers a ComponentListener
or not.