StateMachineBuilder 计时器崩溃

Question

我用SpringStateMachineBuilder创建了一个Bean。

在机器中，我有一个每秒重复一次的 Action。

这是要演示的最小生成器代码：

@Bean
public StateMachine<State, Event> getStateMachine() throws Exception {
    Action action = s -> {};
    Builder<State, Event> builder = StateMachineBuilder.builder();

    builder.configureConfiguration()
            .withConfiguration()
            .autoStartup(true)
            .taskExecutor(new SyncTaskExecutor())
            .taskScheduler(new ConcurrentTaskScheduler());

    builder.configureStates()
            .withStates()
            .initial(State.STARTING)
            .state(State.ACTION, action, null)
            .end(State.DONE)
            .states(EnumSet.allOf(State.class));

    builder.configureTransitions()
            .withExternal()
            .source(State.STARTING).target(State.ACTION).event(Event.START)
            .and().withInternal()
            .source(State.ACTION)
            .action(action)
            .timer(1000)

            .and().withExternal()
            .source(State.ACTION).target(State.DONE).event(Event.STOP);

    return builder.build();
}

无法创建 bean，出现此错误：

Caused by: java.lang.NullPointerException
    at org.springframework.statemachine.trigger.TimerTrigger.doStart(TimerTrigger.java:51)
    at org.springframework.statemachine.support.LifecycleObjectSupport.start(LifecycleObjectSupport.java:120)
    at org.springframework.statemachine.support.DefaultStateMachineExecutor.registerTriggerListener(DefaultStateMachineExecutor.java:415)
    at org.springframework.statemachine.support.DefaultStateMachineExecutor.<init>(DefaultStateMachineExecutor.java:116)
    at org.springframework.statemachine.support.AbstractStateMachine.onInit(AbstractStateMachine.java:258)
    at org.springframework.statemachine.support.LifecycleObjectSupport.afterPropertiesSet(LifecycleObjectSupport.java:67)
    at org.springframework.statemachine.config.ObjectStateMachineFactory.buildStateMachineInternal(ObjectStateMachineFactory.java:79)
    at org.springframework.statemachine.config.AbstractStateMachineFactory.buildMachine(AbstractStateMachineFactory.java:547)
    at org.springframework.statemachine.config.AbstractStateMachineFactory.getStateMachine(AbstractStateMachineFactory.java:193)
    at org.springframework.statemachine.config.StateMachineBuilder$Builder.build(StateMachineBuilder.java:128)

如果我删除 withInternal() [...] .timer(1000)，它可以工作，但我失去了重复功能。

我的生成器代码有什么问题？

Answer 1

我认为这是 spring 状态机中的错误。只有当您使用 StateMachineBuilder 而不是使用 springboot 配置您的 StateMachine 时才会发生这种情况。

在 AbstractStateMachineFactory.java 中，它在创建 TimerTrigger 的新实例时不会在 TimerTrigger 上设置 taskScheduler。我能够通过添加来解决这个问题：

AbstractStateMachineFactory.java : 547

if( taskScheduler != null )
{
  t.setTaskScheduler(taskScheduler);
}

我在此处向项目提交了拉取请求 #178。

StateMachineBuilder 计时器崩溃

Crash on StateMachineBuilder timer

java

spring

exception

state-machine