code: public void fireEvent(final WorkerEvent event, final Worker worker, final String queue, final Job job, 
              final Object runner, final Object result, final Throwable t) {
          final ConcurrentSet<WorkerListener> listeners = this.eventListenerMap.get(event);
          if (listeners != null) {
              for (final WorkerListener listener : listeners) {
                  if (listener != null) {
                      try {
                          listener.onEvent(event, worker, queue, job, runner, result, t);
                      } catch (Exception e) {
                          log.error("Failure executing listener " + listener + " for event " + event 
                                  + " from queue " + queue + " on worker " + worker, e);
                      }
                  }
              }
          }
      }
docs: Notify all WorkerListeners currently registered for the given WorkerEvent.
  @param event the WorkerEvent that occurred
  @param worker the Worker that the event occurred in
  @param queue the queue the Worker is processing
  @param job the Job related to the event (only supply for JOB_PROCESS, JOB_EXECUTE, JOB_SUCCESS, and
  JOB_FAILURE events)
  @param runner the materialized object that the Job specified (only supply for JOB_EXECUTE and
  JOB_SUCCESS events)
  @param result the result of the successful execution of the Job (only set for JOB_SUCCESS and if the Job was
  a Callable that returned a value)
  @param t the Throwable that caused the event (only supply for JOB_FAILURE and ERROR events)