hi,

you could use PApplet to register your mouse/keyEvents like this:
(like explained here http://dev.processing.org/libraries/ )

class gamePiece {

 gamePiece(...) {
   parent.registerMouseEvent(this);
 }

 public void mouseEvent(MouseEvent event) {
 int x = event.getX();
 int y = event.getY();

 switch (event.getID()) {
   case MouseEvent.MOUSE_PRESSED:
     // do something for the mouse being pressed
     break;
   case MouseEvent.MOUSE_RELEASED:
     // do something for mouse released
     break;
   case MouseEvent.MOUSE_CLICKED:
     // do something for mouse clicked
     break;
   case MouseEvent.MOUSE_DRAGGED:
     // do something for mouse dragged
     break;
   case MouseEvent.MOUSE_MOVED:
     // umm...
     break;
 }
}

}