@Override public void cancel(){
  if (cancelable && !canceled) {
    canceled=true;
    firePropertyChange(CANCELED_PROPERTY,false,true);
    if (doCancel != null)     doCancel.run();
  }
}

@ Override public void cancel ( ) { if ( cancelable && ! canceled ) { canceled = true ; firePropertyChange ( CANCELED_PROPERTY , false , true ) ; if ( doCancel != null ) doCancel . run ( ) ; } }
cancels the operation . this method must be invoked from the user event dispatch thread .
