protected void afterEnd(Map<?, ?> flags, Task<?> task) {
    activeTaskCount.decrementAndGet();
    incompleteTaskCount.decrementAndGet();

    if (log.isTraceEnabled()) log.trace(this + " afterEnd, task: " + task);
    ExecutionUtils.invoke(flags.get("newTaskEndCallback"), task);

    PerThreadCurrentTaskHolder.perThreadCurrentTask.remove();
    ((TaskInternal<?>) task).setEndTimeUtc(System.currentTimeMillis());
    // clear thread _after_ endTime set, so we won't get a null thread when there is no end-time
    if (RENAME_THREADS) {
      String newThreadName = "brooklyn-" + Identifiers.makeRandomId(8);
      task.getThread().setName(newThreadName);
    }
    ((TaskInternal<?>) task).setThread(null);
    synchronized (task) {
      task.notifyAll();
    }

    for (ExecutionListener listener : listeners) {
      try {
        listener.onTaskDone(task);
      } catch (Exception e) {
        log.warn("Error notifying listener " + listener + " of task " + task + " done", e);
      }
    }
  }
  protected void beforeStart(Map<?, ?> flags, Task<?> task) {
    activeTaskCount.incrementAndGet();

    // set thread _before_ start time, so we won't get a null thread when there is a start-time
    if (log.isTraceEnabled()) log.trace("" + this + " beforeStart, task: " + task);
    if (!task.isCancelled()) {
      ((TaskInternal<?>) task).setThread(Thread.currentThread());
      if (RENAME_THREADS) {
        String newThreadName =
            "brooklyn-"
                + CaseFormat.LOWER_HYPHEN.to(
                    CaseFormat.LOWER_CAMEL, task.getDisplayName().replace(" ", ""))
                + "-"
                + task.getId().substring(0, 8);
        task.getThread().setName(newThreadName);
      }
      PerThreadCurrentTaskHolder.perThreadCurrentTask.set(task);
      ((TaskInternal<?>) task).setStartTimeUtc(System.currentTimeMillis());
    }
    ExecutionUtils.invoke(flags.get("newTaskStartCallback"), task);
  }