question: protected int mapDragOperationFromModifiers ( MouseEvent e ) { int mods = e . getModifiersEx ( ) ; int btns = mods & ButtonMask ; if ( ! ( btns == InputEvent . BUTTON1_DOWN_MASK || btns == InputEvent . BUTTON2_DOWN_MASK ) ) { return DnDConstants . ACTION_NONE ; } return SunDragSourceContextPeer . convertModifiersToDropAction ( mods , getSourceActions ( ) ) ; }
target:  determine the drop action from the event