spring statemachine的企业可用级开发指南4-多种状态机共存

        在上一章的例子中，咱们实现了多个状态机并存执行，不一样的订单有各自的状态机运行，但只有一种状态机，这显然不能知足实际业务的要求，好比我就遇到了订单流程和公文审批流程在同一个项目的状况，因此咱们这一章讲怎么让多种状态机共存。

        咱们先把上一章的例子状态机再复习一下，这是个订单状态机，流程图以下：

        

    定义这个状态机咱们用到了OrderEvents，OrderStates来表达状态（states）和事件（events），用OrderStateMachineBuilder来描述初始状态和状态变化流程，用OrderEventConfig来描述这个流程和状态变化过程当中须要作的业务。

    如今咱们再弄一个新的状态机流程，表单状态机，流程图以下：

    

    为此，咱们一样配套了和订单状态机同样的表单四件套，events，states，StateMachineBuilder和eventConfig。

public enum FormStates {
	BLANK_FORM, // 空白表单
	FULL_FORM, // 填写完表单
	CONFIRM_FORM, // 校验表单
	SUCCESS_FORM// 成功表单
}

public enum FormEvents {
	WRITE, // 填写
	CONFIRM, // 校验
	SUBMIT // 提交
}

import java.util.EnumSet;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.statemachine.StateMachine;
import org.springframework.statemachine.config.StateMachineBuilder;
import org.springframework.stereotype.Component;

/**
 * 订单状态机构建器
 */
@Component
public class FormStateMachineBuilder {

	private final static String MACHINEID = "formMachine";
	
	 /**
	  * 构建状态机
	  * 
	 * @param beanFactory
	 * @return
	 * @throws Exception
	 */
	public StateMachine<FormStates, FormEvents> build(BeanFactory beanFactory) throws Exception {
		 StateMachineBuilder.Builder<FormStates, FormEvents> builder = StateMachineBuilder.builder();
		 
		 System.out.println("构建表单状态机");
		 
		 builder.configureConfiguration()
		 		.withConfiguration()
		 		.machineId(MACHINEID)
		 		.beanFactory(beanFactory);
		 
		 builder.configureStates()
		 			.withStates()
		 			.initial(FormStates.BLANK_FORM)
		 			.states(EnumSet.allOf(FormStates.class));
		 			
		 builder.configureTransitions()
					 .withExternal()
						.source(FormStates.BLANK_FORM).target(FormStates.FULL_FORM)
						.event(FormEvents.WRITE)
						.and()
					.withExternal()
						.source(FormStates.FULL_FORM).target(FormStates.CONFIRM_FORM)
						.event(FormEvents.CONFIRM)
						.and()
					.withExternal()
						.source(FormStates.CONFIRM_FORM).target(FormStates.SUCCESS_FORM)
						.event(FormEvents.SUBMIT);
		 			
		 return builder.build();
	 }
	
}

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.messaging.Message;
import org.springframework.statemachine.annotation.OnTransition;
import org.springframework.statemachine.annotation.WithStateMachine;

@WithStateMachine(id="formMachine")
public class FormEventConfig {
private Logger logger = LoggerFactory.getLogger(getClass());
	
    /**
     * 当前状态BLANK_FORM
     */
    @OnTransition(target = "BLANK_FORM")
    public void create() {
        logger.info("---空白表单---");
    }
    
    /**
     * BLANK_FORM->FULL_FORM 执行的动做
     */
    @OnTransition(source = "BLANK_FORM", target = "FULL_FORM")
    public void write(Message<FormEvents> message) {
        logger.info("---填写完表单---");
    }
    
    /**
     * FULL_FORM->CONFIRM_FORM 执行的动做
     */
    @OnTransition(source = "FULL_FORM", target = "CONFIRM_FORM")
    public void confirm(Message<FormEvents> message) {
        logger.info("---校验表单---");
    }
    
    /**
     * CONFIRM_FORM->SUCCESS_FORM 执行的动做
     */
    @OnTransition(source = "CONFIRM_FORM", target = "SUCCESS_FORM")
    public void submit(Message<FormEvents> message) {
        logger.info("---表单提交成功---");
    }

}

从代码能够看到深深的套路感，里面除了对流程状态的描述不一样外，另一个不一样点就是MACHINEID，在不一样的状态机流程中，用MACHINEID来标识不一样就能使用多种状态机了，对比一下就很清楚。在builder里面经过MACHINEID来区分

private final static String MACHINEID = "orderMachine";

	public StateMachine<OrderStates, OrderEvents> build(BeanFactory beanFactory) throws Exception {
		 StateMachineBuilder.Builder<OrderStates, OrderEvents> builder = StateMachineBuilder.builder();
		 
		 System.out.println("构建订单状态机");
		 
		 builder.configureConfiguration()
		 		.withConfiguration()
		 		.machineId(MACHINEID)
		 		.beanFactory(beanFactory);
...

private final static String MACHINEID = "formMachine";

	public StateMachine<FormStates, FormEvents> build(BeanFactory beanFactory) throws Exception {
		 StateMachineBuilder.Builder<FormStates, FormEvents> builder = StateMachineBuilder.builder();
		 
		 System.out.println("构建表单状态机");
		 
		 builder.configureConfiguration()
		 		.withConfiguration()
		 		.machineId(MACHINEID)
		 		.beanFactory(beanFactory);
...

对应的在eventconfig里面

@WithStateMachine(id="orderMachine")
public class OrderEventConfig {
...

@WithStateMachine(id="formMachine")
public class FormEventConfig {

经过@WithStateMachine注解的id参数就区分出来了不一样的状态机，这个id就是builder里面定义的MACHINEID。而后就是怎么引用的问题了，咱们来看controller

@Autowired
	private OrderStateMachineBuilder orderStateMachineBuilder;
	
	@Autowired
	private FormStateMachineBuilder formStateMachineBuilder;

这样，不一样的builder就能同时引用，两种状态机就互不干扰的各自运行了，这是运行的代码：

@RequestMapping("/testOrderState")
	public void testOrderState(String orderId) throws Exception {

		StateMachine<OrderStates, OrderEvents> stateMachine = orderStateMachineBuilder.build(beanFactory);
		System.out.println(stateMachine.getId());

		// 建立流程
		stateMachine.start();

		// 触发PAY事件
		stateMachine.sendEvent(OrderEvents.PAY);

		// 触发RECEIVE事件
		stateMachine.sendEvent(OrderEvents.RECEIVE);


		// 获取最终状态
		System.out.println("最终状态：" + stateMachine.getState().getId());
	}
	
	@RequestMapping("/testFormState")
	public void testFormState() throws Exception {

		StateMachine<FormStates, FormEvents> stateMachine = formStateMachineBuilder.build(beanFactory);
		System.out.println(stateMachine.getId());

		// 建立流程
		stateMachine.start();

		stateMachine.sendEvent(FormEvents.WRITE);

		stateMachine.sendEvent(FormEvents.CONFIRM);

		stateMachine.sendEvent(FormEvents.SUBMIT);

		// 获取最终状态
		System.out.println("最终状态：" + stateMachine.getState().getId());
	}

分别执行

http://localhost:9991/statemachine/testOrderState 使用StateMachineBuilder建立的多个状态机演示
http://localhost:9991/statemachine/testFormState 多种状态机的演示（上面都是order的状态机，这个是form的状态机）

在日志里面就能看到各自状态机的运行结果了。

目前为止，多个状态机和多种状态机均可以在spring statemachine里面实现了，下一章咱们来解决下状态机和实际业务间的数据传输问题，毕竟咱们不是为了让状态机自个独自玩耍，和业务数据互通有无才是企业开发的正道。

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