public boolean run()

in tez-dag/src/main/java/org/apache/tez/runtime/task/TezTaskRunner.java [90:165]
64 lines of code
14 McCabe index (conditional complexity)

  public boolean run() throws InterruptedException, IOException, TezException {
    waitingThread = Thread.currentThread();
    TaskRunnerCallable callable = new TaskRunnerCallable();
    Throwable failureCause = null;
    taskFuture = executor.submit(callable);
    try {
      taskFuture.get();

      // Task could signal a fatal error and return control, or a failure while registering success.
      failureCause = firstException;

    } catch (InterruptedException e) {
      LOG.info("Interrupted while waiting for task to complete. Interrupting task");
      taskFuture.cancel(true);
      if (shutdownRequested.get()) {
        LOG.info("Shutdown requested... returning");
        return false;
      }
      if (firstException != null) {
        failureCause = firstException;
      } else {
        // Interrupted for some other reason.
        failureCause = e;
      }
    } catch (ExecutionException e) {
      // Exception thrown by the run() method itself.
      Throwable cause = e.getCause();
      if (cause instanceof FSError) {
        // Not immediately fatal, this is an error reported by Hadoop FileSystem
        failureCause = cause;
      } else if (cause instanceof Error) {
        LOG.error("Exception of type Error. Exiting now", cause);
        ExitUtil.terminate(-1, cause);
        // Effectively dead code. Must return something.
        assert(false);
        return false;
      } else {
        failureCause = cause;
      }
    } finally {
      // Clear the interrupted status of the blocking thread, in case it is set after the
      // InterruptedException was invoked.
      taskReporter.unregisterTask(task.getTaskAttemptID());
      Thread.interrupted();
    }

    if (failureCause != null) {
      if (failureCause instanceof FSError) {
        // Not immediately fatal, this is an error reported by Hadoop FileSystem
        LOG.info("Encountered an FSError while executing task: " + task.getTaskAttemptID(),
            failureCause);
        throw (FSError) failureCause;
      } else if (failureCause instanceof Error) {
        LOG.error("Exception of type Error. Exiting now", failureCause);
        ExitUtil.terminate(-1, failureCause);
        // Effectively dead code. Must return something.
        assert(false);
        return false;
      } else {
        if (failureCause instanceof IOException) {
          throw (IOException) failureCause;
        } else if (failureCause instanceof TezException) {
          throw (TezException) failureCause;
        } else if (failureCause instanceof InterruptedException) {
          throw (InterruptedException) failureCause;
        } else {
          throw new TezException(failureCause);
        }
      }
    }
    if (shutdownRequested.get()) {
      LOG.info("Shutdown requested... returning");
      return false;
    }
    return true;
  }