private void changeUpdateStatus(
      MutableStoreProvider storeProvider, IJobUpdateSummary updateSummary, JobUpdateEvent event)
      throws UpdateStateException {

    if (updateSummary.getState().getStatus() == event.getStatus()) {
      return;
    }

    assertTransitionAllowed(updateSummary.getState().getStatus(), event.getStatus());
    recordAndChangeJobUpdateStatus(storeProvider, updateSummary.getKey(), event);
  }
  private void changeJobUpdateStatus(
      MutableStoreProvider storeProvider,
      IJobUpdateKey key,
      JobUpdateEvent proposedEvent,
      boolean recordChange)
      throws UpdateStateException {

    JobUpdateStatus status;
    boolean record;

    JobUpdateStore.Mutable updateStore = storeProvider.getJobUpdateStore();
    Optional<String> updateLock = updateStore.getLockToken(key);
    if (updateLock.isPresent()) {
      status = proposedEvent.getStatus();
      record = recordChange;
    } else {
      LOG.severe("Update " + key + " does not have a lock");
      status = ERROR;
      record = true;
    }

    LOG.info(String.format("Update %s is now in state %s", key, status));
    if (record) {
      updateStore.saveJobUpdateEvent(
          key,
          IJobUpdateEvent.build(proposedEvent.setTimestampMs(clock.nowMillis()).setStatus(status)));
    }

    if (TERMINAL_STATES.contains(status)) {
      if (updateLock.isPresent()) {
        lockManager.releaseLock(
            ILock.build(
                new Lock()
                    .setKey(LockKey.job(key.getJob().newBuilder()))
                    .setToken(updateLock.get())));
      }

      pulseHandler.remove(key);
    } else {
      pulseHandler.updatePulseStatus(key, status);
    }

    MonitorAction action = JobUpdateStateMachine.getActionForStatus(status);
    IJobKey job = key.getJob();
    if (action == STOP_WATCHING) {
      updates.remove(job);
    } else if (action == ROLL_FORWARD || action == ROLL_BACK) {
      if (action == ROLL_BACK) {
        updates.remove(job);
      } else {
        checkState(!updates.containsKey(job), "Updater already exists for " + job);
      }

      IJobUpdate jobUpdate = updateStore.fetchJobUpdate(key).get();
      UpdateFactory.Update update;
      try {
        update = updateFactory.newUpdate(jobUpdate.getInstructions(), action == ROLL_FORWARD);
      } catch (RuntimeException e) {
        LOG.log(Level.WARNING, "Uncaught exception: " + e, e);
        changeJobUpdateStatus(
            storeProvider,
            key,
            newEvent(ERROR).setMessage("Internal scheduler error: " + e.getMessage()),
            true);
        return;
      }
      updates.put(job, update);
      evaluateUpdater(storeProvider, update, jobUpdate.getSummary(), ImmutableMap.of());
    }
  }