protected void fireChangeListeners(){
  if (listeners == null)   return;
  for (int a=0; a < listeners.size(); a++) {
    ChangeListener l=listeners.get(a);
    try {
      l.stateChanged(new ChangeEvent(this));
    }
 catch (    Exception e) {
      e.printStackTrace();
    }
  }
}

protected void fireChangeListeners ( ) { if ( listeners == null ) return ; for ( int a = 0 ; a < listeners . size ( ) ; a ++ ) { ChangeListener l = listeners . get ( a ) ; try { l . stateChanged ( new ChangeEvent ( this ) ) ; } catch ( Exception e ) { e . printStackTrace ( ) ; } } }
fires all change listeners
