private void actOnExists()

in twill-core/src/main/java/org/apache/twill/internal/AbstractZKServiceController.java [167:196]

26 lines of code
6 McCabe index (conditional complexity)


  private void actOnExists(final String path, final Runnable action) {
    // Watch for node existence.
    final AtomicBoolean nodeExists = new AtomicBoolean(false);
    Futures.addCallback(zkClient.exists(path, new Watcher() {
      @Override
      public void process(WatchedEvent event) {
        if (!shouldProcessZKEvent()) {
          return;
        }
        // When node is created, call the action.
        // Other event type would be handled by the action.
        if (event.getType() == Event.EventType.NodeCreated && nodeExists.compareAndSet(false, true)) {
          action.run();
        }
      }
    }), new FutureCallback<Stat>() {
      @Override
      public void onSuccess(Stat result) {
        if (result != null && nodeExists.compareAndSet(false, true)) {
          action.run();
        }
      }

      @Override
      public void onFailure(Throwable t) {
        LOG.error("Failed in exists call to {}. Shutting down service.", path, t);
        forceShutDown();
      }
    }, Threads.SAME_THREAD_EXECUTOR);
  }