void addListenerByProbe ( ProbeImpl probe , ProbeListener listener ) { Set < ProbeListener > listeners = listenersByProbe . get ( probe ) ; if ( listeners == null ) { listeners = new CopyOnWriteArraySet < ProbeListener > ( ) ; listenersByProbe . putIfAbsent ( probe , listeners ) ; listeners = listenersByProbe . get ( probe ) ; } listeners . add ( listener ) ; }
Add the specified listener to the collection of listeners associated with the specified probe .