我想使用timerOnce来延迟，但它不起作用

Question

我想从状态REPEATED_EXPORT_TO_A转到状态EXPORT_TO_A_AGAIN但有延迟但是动作reexportEvent（）没有执行。我有以下状态机：

    public StateMachineBuilder.Builder<StatusId, ActionId> construct(StateMachineBuilder.Builder<StatusId, ActionId> builder) throws Exception {
builder.configureStates().withStates()
        .states(ImmutableSet.of(OBTAINED_BY_B, FOR_EXPORT_TO_A, EXPORTING_TO_A,
                EXPORT_TO_A_ERROR, EXPORTING_TO_A_TIMEOUT,
                RECEIVED_BY_A, NOT_RECEIVED_BY_A, RECEIVED_A_ERROR, REPEATED_EXPORT_TO_A))
        .state(FOR_EXPORT_TO_A, checkPassedAction(), null)
        .state(EXPORTING_TO_A, exportedAction(), null)

        .choice(EXPORTED_TO_A_OR_NOT)
        .choice(EXPORT_TO_A_AGAIN);

builder.configureTransitions().withExternal()
        .source(OBTAINED_BY_B).target(FOR_EXPORT_TO_A)
        .and().withExternal()
        .source(FOR_EXPORT_TO_A).target(EXPORTED_TO_A_OR_NOT)

        .and().withChoice()
        .source(EXPORTED_TO_A_OR_NOT)
        .first(EXPORTING_TO_A, exportingToAGuardSsm)
        .last(REPEATED_EXPORT_TO_A)

        .and().withExternal()
        .source(REPEATED_EXPORT_TO_A)
        .target(EXPORT_TO_A_AGAIN)
        .event(REEXPORT_TO_A)

        .and().withChoice()
        .source(EXPORT_TO_A_AGAIN)
        .first(EXPORTING_TO_A, exportingToAGuardSsm)
        .then(EXPORT_TO_A_ERROR, checkRepeatExportGuard)
        .then(REPEATED_EXPORT_TO_A, repeatExportToBGuardSsm)
        .last(EXPORT_TO_A_ERROR)

这种内部过渡是为了延迟

   .and().withInternal()
    .source(REPEATED_EXPORT_TO_A)
    .action(reexportEvent())
    .timerOnce(5000)

但是这个动作还没有执行

 private Action<StatusId, ActionId> reexportEvent() {
    //some code
      return context -> {
          Doc doc = SsmUtil.getDoc(context);
          doc.setRepeatCount(doc.getRepeatCount() + 1);
          context.getStateMachine().sendEvent(REEXPORT_TO_A);
      };
  }

Answer 1

有一个关键的事情要理解Spring State Machine中的触发器 - 它们与状态相关联，您需要保持该状态才能执行触发器。延迟从您进入状态开始 - 如果您在达到延迟时间之前退出状态，则触发器不会执行。

例：

• 指定状态为“A”的触发器，延迟为5秒
• 输入状态“A”
• 在第二个第二个退出状态“A”

触发器不会执行，因为您在定义的时间延迟到期之前退出了状态“A”。

签出一个单元测试（TestTriggersDelay）来演示这种行为here。