spring boot +spring stateMachine启蒙程序

提前准备
jar包：gradle

dependencies {

    compile(
            "org.springframework.boot:spring-boot-starter-web:${springBootVersion}",
            "org.springframework.statemachine:spring-statemachine-core:1.2.0.RELEASE",
    )
}

先定义state
state 就是程序中某事物运行时的各种状态

public  enum  States {
    ADD,
    MODIFY,
    CANCEL
}

再定义触发事件
event ：改变状态的触发事件

public enum Events {
    PICK_UP,
    GIVE_UP,
    DROP
}

配置stateConfig
配置事件event、状态state的关系

@Configuration
@EnableStateMachine
public class StatesConfig extends EnumStateMachineConfigurerAdapter {

    @Override
    public void configure(StateMachineStateConfigurer Statess) throws Exception {
        Statess.withStates()
                .initial(States.ADD)
                .states(EnumSet.allOf(States.class));
    }

    //
    @Override
    public void configure(StateMachineConfigurationConfigurer config)
            throws Exception {
        config
                .withConfiguration()
                .autoStartup(true)
                .listener(listener());
    }

    @Override
    public void configure(StateMachineTransitionConfigurer transitions) throws Exception {
        transitions
                .withExternal()
                    .source(States.ADD)
                    .target(States.MODIFY)
                    .event(Events.PICK_UP)
                    .and()
                .withExternal()
                    .source(States.ADD)
                    .target(States.CANCEL)
                    .event(Events.DROP)
                    .and()
                .withExternal()
                    .source(States.MODIFY)
                    .target(States.CANCEL)
                    .event(Events.GIVE_UP);
    }

    @Bean
    public StateMachineListener listener() {
        return new StateMachineListenerAdapter() {
            @Override
            public void stateChanged(State from, State to) {
                System.out.println("state change ... " + to.getId());
            }
        };
    }
}

触发事件

@Component
public class EventSend implements CommandLineRunner {

    @Autowired
    StateMachine stateMachine;

    //发送事件  
    @Override
    public void run(String... args) throws Exception {
        stateMachine.start();
        stateMachine.sendEvent(Events.PICK_UP);
        stateMachine.sendEvent(Events.GIVE_UP);
        stateMachine.sendEvent(Events.DROP);
    }
}

使用spring boot 启动项目

@SpringBootApplication
public class Application{

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

期望输出结果：

state change ... ADD
state change ... MODIFY
state change ... CANCEL