private void layoutControl(){
  controlPanel.add(previousSource,BorderLayout.WEST);
  controlPanel.add(nextSource,BorderLayout.EAST);
  controlPanel.add(informationButton,BorderLayout.CENTER);
}

private void layoutControl ( ) { controlPanel . add ( previousSource , BorderLayout . WEST ) ; controlPanel . add ( nextSource , BorderLayout . EAST ) ; controlPanel . add ( informationButton , BorderLayout . CENTER ) ; }
lays out the control buttons of this frame .
