question: public static int isButtonOnScreen ( final String buttonKey ) { Component onScreen ; try { onScreen = BubbleWindow . findButton ( buttonKey , RapidMinerGUI . getMainFrame ( ) ) ; } catch ( NullPointerException e ) { return OBJECT_NOT_ON_SCREEN ; } if ( onScreen == null ) { return OBJECT_NOT_ON_SCREEN ; } int xposition = onScreen . getLocationOnScreen ( ) . x ; int yposition = onScreen . getLocationOnScreen ( ) . y ; int otherXposition = xposition + onScreen . getWidth ( ) ; int otherYposition = yposition + onScreen . getHeight ( ) ; Window frame = RapidMinerGUI . getMainFrame ( ) ; if ( otherXposition <= frame . getWidth ( ) && otherYposition <= frame . getHeight ( ) && xposition > 0 && yposition > 0 ) { return OBJECT_SHOWING_ON_SCREEN ; } else { return OBJECT_NOT_SHOWING ; } }
target:  method to get to know whether the AbstractButton with the given key is on Screen