public void process()

in twill-zookeeper/src/main/java/org/apache/twill/internal/zookeeper/LeaderElection.java [376:412]
32 lines of code
13 McCabe index (conditional complexity)

    public void process(WatchedEvent event) {
      switch (event.getState()) {
        case Disconnected:
          disconnected = true;
          LOG.info("Disconnected from ZK: {} for {}", zkClient.getConnectString(), zkFolderPath);
          if (state == State.LEADER) {
            // becomeFollower has to be called in disconnect so that no two active leader is possible.
            LOG.info("Stepping down as leader due to disconnect: {} for {}", zkClient.getConnectString(), zkFolderPath);
            becomeFollower();
          }
          break;
        case SyncConnected:
          boolean runElection = disconnected && !expired && state != State.IN_PROGRESS;
          boolean runRegister = disconnected && expired && state != State.IN_PROGRESS;
          disconnected = false;
          expired = false;
          if (runElection) {
            // If the state is cancelled (meaning a cancel happens between disconnect and connect),
            // still runElection() so that it has chance to delete the node (as it's not expired, the node stays
            // after reconnection).
            if (state != State.CANCELLED) {
              state = State.IN_PROGRESS;
            }
            LOG.info("Connected to ZK, running election: {} for {}", zkClient.getConnectString(), zkFolderPath);
            runElection();
          } else if (runRegister && state != State.CANCELLED) {
            LOG.info("Connected to ZK, registering: {} for {}", zkClient.getConnectString(), zkFolderPath);
            register();
          }

          break;
        case Expired:
          LOG.info("ZK session expired: {} for {}", zkClient.getConnectString(), zkFolderPath);
          expired = true;
          break;
      }
    }