Question

我在一个非常简单的场景中配置SSM时遇到了问题：

罪魁祸首是触发 log_on 事件时需要执行的“验证”操作。我重读了SSM文档，不确定这是“fork”，“guard”还是分层配置。

'动作'在这里执行：

@Component
public class LogonValidationAction implements Action<PickStates, PickEvents> {

Logger logger = LogManager.getLogger();

volatile int counter = 0;

@Override
public void execute(StateContext<PickStates, PickEvents> context) {
    String eventName = context.getEvent().name();
    logger.info("executing {} for event {}", LogonValidationAction.class.getName(), eventName);

    // basically, if success, send success, if failure, send failure
    // for testing
    if(counter % 2 == 0)
        context.getStateMachine().sendEvent(PickEvents.logon_sucess);
    else
        context.getStateMachine().sendEvent(PickEvents.logon_fail);
}
}

我在测试中使用'counter'来指示流程为'failure'（logged_off状态保持）或'success'（状态更改为logged_on）。

这是配置：

@Configuration
@EnableStateMachineFactory
public class Config extends EnumStateMachineConfigurerAdapter<PickStates, PickEvents>{

@Autowired
StateMachineListener stateMachineListener;

@Autowired
LogonValidationAction logonValidationAction;

@Override
public void configure(StateMachineStateConfigurer<PickStates, PickEvents> states) throws Exception {
    states
        .withStates()
        .initial(PickStates.logged_off)
        .state(PickStates.logged_on)
        .states(EnumSet.allOf(PickStates.class));
}

@Override
public void configure(StateMachineTransitionConfigurer<PickStates, PickEvents> transitions) throws Exception {
    transitions
        .withExternal()
        .source(PickStates.logged_off)
        .target(PickStates.logged_on)
        .event(PickEvents.log_on)
        .action(logonValidationAction)
        .and()
        .withExternal()
        .source(PickStates.logged_on)
        .target(PickStates.logged_off)
        .event(PickEvents.log_off);
}

@Override
public void configure(StateMachineConfigurationConfigurer<PickStates, PickEvents> config) throws Exception {
    config
        .withConfiguration()
        .autoStartup(true)
        .listener(stateMachineListener);
}
}

这是失败的测试（当操作触发logon_fail事件时，期望'logged_off'）：

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = Application.class)
public class EzpickStateMachineTest {

Logger logger = LogManager.getLogger();

@Autowired
StateMachineFactory<PickStates, PickEvents> stateMachineFactory;

// for testing so can toggle success/failure when logging in
@Autowired
LogonValidationAction logonValidationAction;

@Test
public void failLogon() throws Exception {
    StateMachine<PickStates, PickEvents> stateMachine = stateMachineFactory.getStateMachine();

    stateMachine.start();

    // when sm starts, state is 'logged_off'
    assertThat(stateMachine.getState().getId().name(), is(PickStates.logged_off.name()));

    // odd numbers fire 'failure' event
    logonValidationAction.setCounter(1);

    stateMachine.sendEvent(PickEvents.log_on);

    // if logon fails, state is 'logged_off'
    assertThat(stateMachine.getState().getId().name(), is(PickStates.logged_off.name()));
}
}

Answer 1

您可以尝试发送logon_sucess或logon_fail，但在机器配置中，您尚未为这些事件定义任何转换，因此计算机不会执行任何操作。

其他注意事项，不要在动作bean中存储counter，为它使用机器扩展状态变量，因为它使用机器或StateContext对每个组件都可见。

当counter在扩展状态下可用时，您可以使用从扩展状态使用该计数器的保护来创建匿名转换。另一种可能性是使用选择伪状态和保护来在目标状态之间做出选择。您对计数器的使用正是维基在其扩展状态部分https://en.wikipedia.org/wiki/UML_state_machine#Extended_states

中提到的

弹簧状态机根据动作改变为两种可能状态之一

1 个答案: