StateMachine 状态机机制深入解析

<dependency>
 <groupId>org.springframework.statemachine</groupId>
  <artifactId>spring-statemachine-core</artifactId>
  <version>1.2.0.RELEASE</version>
</dependency>

public enum RegStatusEnum {
  // 未连接
  UNCONNECTED,
  // 已连接
  CONNECTED,
  // 注册中
  REGISTERING,
  // 已注册
  REGISTERED; 
}

public enum RegEventEnum {
  // 连接
  CONNECT,
  // 注册
  REGISTER,
  // 注册成功
  REGISTER_SUCCESS,
  // 注册失败
  REGISTER_FAILED,
  // 注销
  UN_REGISTER;
}

@Configuration
@EnableStateMachine
public class StateMachineConfig extends EnumStateMachineConfigurerAdapter<RegStatusEnum, RegEventEnum> {
}

@Override
public void configure(StateMachineStateConfigurer<RegStatusEnum, RegEventEnum> states) throws Exception {
  states.withStates()
  // 定义初始状态
  .initial(RegStatusEnum.UNCONNECTED)
  // 定义状态机状态
  .states(EnumSet.allOf(RegStatusEnum.class));
} 

@Override
public void configure(StateMachineTransitionConfigurer<RegStatusEnum, RegEventEnum> transitions)
    throws Exception {
  transitions
    // 1.连接事件
    // 未连接 -> 已连接
    .withExternal()
      .source(RegStatusEnum.UNCONNECTED)
      .target(RegStatusEnum.CONNECTED)
      .event(RegEventEnum.CONNECT)
    .and()           
 
    // 2.注册事件  
    // 已连接 -> 注册中
    .withExternal()
      .source(RegStatusEnum.CONNECTED)
      .target(RegStatusEnum.REGISTERING)
      .event(RegEventEnum.REGISTER)
    .and()
 
    // 3.注册成功事件  
    // 注册中 -> 已注册
    .withExternal()
      .source(RegStatusEnum.REGISTERING)
      .target(RegStatusEnum.REGISTERED)
      .event(RegEventEnum.REGISTER_SUCCESS)
    .and()
 
    // 5.注销事件
    // 已连接 -> 未连接
    .withExternal()
      .source(RegStatusEnum.CONNECTED)
      .target(RegStatusEnum.UNCONNECTED)
      .event(RegEventEnum.UN_REGISTER)
    .and()
    // 注册中 -> 未连接
    .withExternal()
      .source(RegStatusEnum.REGISTERING)
      .target(RegStatusEnum.UNCONNECTED)
      .event(RegEventEnum.UN_REGISTER)
    .and()
    // 已注册 -> 未连接
    .withExternal()
      .source(RegStatusEnum.REGISTERED)
      .target(RegStatusEnum.UNCONNECTED)
      .event(RegEventEnum.UN_REGISTER)
    ;
}

// 未连接 -> 已连接
.withExternal()
  .source(RegStatusEnum.UNCONNECTED)
  .target(RegStatusEnum.CONNECTED)
  .event(RegEventEnum.CONNECT)

@WithStateMachine
public class StateMachineEventConfig { 
  @OnTransition(source = "UNCONNECTED", target = "CONNECTED")
  public void connect() {
    System.out.println("///////////////////");
    System.out.println("连接事件, 未连接 -> 已连接");
    System.out.println("///////////////////");
  } 
  @OnTransition(source = "CONNECTED", target = "REGISTERING")
  public void register() {
    System.out.println("///////////////////");
    System.out.println("注册事件, 已连接 -> 注册中");
    System.out.println("///////////////////");
  } 
  @OnTransition(source = "REGISTERING", target = "REGISTERED")
  public void registerSuccess() {
    System.out.println("///////////////////");
    System.out.println("注册成功事件, 注册中 -> 已注册");
    System.out.println("///////////////////");
  } 
  @OnTransition(source = "REGISTERED", target = "UNCONNECTED")
  public void unRegister() {
    System.out.println("///////////////////");
    System.out.println("注销事件, 已注册 -> 未连接");
    System.out.println("///////////////////");
  }
}