Library that allows for mouse control

I believe that is BUTTON1 – although I haven’t tested the ways of referring to it.

https://docs.oracle.com/javase/7/docs/api/java/awt/event/InputEvent.html

Note in particular:

int button = InputEvent.BUTTON1_MASK
int button = InputEvent.getMaskForButton(1); 
int button = InputEvent.getMaskForButton(MouseEvent.BUTTON1);