spring statemachine 复杂状态机的实现，choice，guard和action

it2024-12-06 11

1、讲讲复杂流程的需求

除了上面文章里面提到的一根筋状态机流程，实际的企业应用中状态机的流程会更加复杂，而我们最常用到的就是choice。它类似于java的if语句，作为条件判断的分支而存在，让我们先看一张图：

这张图表现的是一个表单（form）的整个状态流程：

创建初始的空白表单（ BLANK_FORM）填写(WRITE)表单，成为填充完表单（FULL_FORM）检查(CHEKC)表单如果是表单名（formName）不为null，表单成为待提交表单（CONFIRM_FROM）提交（SUBMIT）表单，成为成功提交表单（SUCCESS_FORM）检查（CHECK）表单如果表单名为null，表单成为待处理表单（DEAL_FORM）,修改formName处理(DEAL)表单如果表单名还是null或者里面有个“坏”字，表单状态变成废单（FAILED_FORM）如果表单名称没问题，表单状态变成填充完表单状态（FULL_FORM）,重新走流程

大家不要在意这个例子的幼稚，毕竟它还是能用简单的方式体现出流程的复杂性（这话多么的辩证统一）。它有判断分支（还有两个），还有流程的循环，还有分支判断后的直接失败和分支判断后的后续环节，后面我们会在代码中告诉大家这里面需要注意的东西。

2、代码实现

先上状态机的四件套：States，Events，Builder和EventConfig（spring statemachine还是蛮简单的，来来回回就这几样东西）

public enum ComplexFormStates { BLANK_FORM, // 空白表单 FULL_FORM, // 填写完表单 CHECK_CHOICE,//表单校验判断 DEAL_CHOICE,//表单处理校验 DEAL_FORM,//待处理表单 CONFIRM_FORM, // 校验完表单 SUCCESS_FORM,// 成功表单 FAILED_FORM//失败表单 }

注意一点，choice判断分支本身也是一种状态，要声明出来，这里是CHECK_CHOICE和DEAL_CHOICE

public enum ComplexFormEvents { WRITE, // 填写 CHECK,//校验 DEAL,//处理 SUBMIT // 提交 }

同样的分支事件也要声明，这里是CHECK和DEAL。

大头是MachineBuilder，这个代码就比较多，大家最好对照着上面这张图来看，会比较清晰

/** * 复杂订单状态机构建器 */ @Component public class ComplexFormStateMachineBuilder { private final static String MACHINEID = "complexFormMachine"; /** * 构建状态机 * * @param beanFactory * @return * @throws Exception */ public StateMachine<ComplexFormStates, ComplexFormEvents> build(BeanFactory beanFactory) throws Exception { StateMachineBuilder.Builder<ComplexFormStates, ComplexFormEvents> builder = StateMachineBuilder.builder(); System.out.println("构建复杂表单状态机"); builder.configureConfiguration() .withConfiguration() .machineId(MACHINEID) .beanFactory(beanFactory); builder.configureStates() .withStates() .initial(ComplexFormStates.BLANK_FORM) .choice(ComplexFormStates.CHECK_CHOICE) .choice(ComplexFormStates.DEAL_CHOICE) .states(EnumSet.allOf(ComplexFormStates.class)); builder.configureTransitions() .withExternal() .source(ComplexFormStates.BLANK_FORM).target(ComplexFormStates.FULL_FORM) .event(ComplexFormEvents.WRITE) .and() .withExternal() .source(ComplexFormStates.FULL_FORM).target(ComplexFormStates.CHECK_CHOICE) .event(ComplexFormEvents.CHECK) .and() .withChoice() .source(ComplexFormStates.CHECK_CHOICE) .first(ComplexFormStates.CONFIRM_FORM, new ComplexFormCheckChoiceGuard()) .last(ComplexFormStates.DEAL_FORM) .and() .withExternal() .source(ComplexFormStates.CONFIRM_FORM).target(ComplexFormStates.SUCCESS_FORM) .event(ComplexFormEvents.SUBMIT) .and() .withExternal() .source(ComplexFormStates.DEAL_FORM).target(ComplexFormStates.DEAL_CHOICE) .event(ComplexFormEvents.DEAL) .and() .withChoice() .source(ComplexFormStates.DEAL_CHOICE) .first(ComplexFormStates.FULL_FORM, new ComplexFormDealChoiceGuard()) .last(ComplexFormStates.FAILED_FORM); return builder.build(); } }

这里面出现了几个新东西，要说一下：

在configureStates时，要把每个分支都要写上去，我之前写了ComplexFormStates.CHECK_CHOICE，忘了写DEAL_CHOICE，后面的choice就不执行，搞得我找了很久，大家要注意（是的，我犯的就是这种简单弱智的错误，我还找了很久）在我们熟悉的withExternal之后，我们迎来了为choice专门准备的withChoice()和跟随它的first()，last()。这两个代表的就是分支判断时TRUE和FALSE的状态流程去处，这里面涉及到的一个问题就是，TRUE和FALSE的判断条件是什么呢，根据啥来判断呢？Guard就承担了这个判断的功能，看名字似乎不像。它在spring statemachine本来是用来保护这个状态跳转过程的，所以用guard，但在choice里面，它就是作为判断代码而存在的，代码如下： public class ComplexFormCheckChoiceGuard implements Guard<ComplexFormStates, ComplexFormEvents> { @Override public boolean evaluate(StateContext<ComplexFormStates, ComplexFormEvents> context) { boolean returnValue = false; Form form = context.getMessage().getHeaders().get("form", Form.class); if (form.formName == null) { returnValue = false; } else { returnValue = true; } return returnValue; } }

它只implements一个方法evaluate()，返回boolean类型，所以很适合做这个判断的功能。另外一个DEAL_CHOICE的gurad代码是这样的

public class ComplexFormDealChoiceGuard implements Guard<ComplexFormStates, ComplexFormEvents> { @Override public boolean evaluate(StateContext<ComplexFormStates, ComplexFormEvents> context) { System.out.println("ComplexFormDealChoiceGuard!!!!!!!!!!!!!"); boolean returnValue = false; Form form = context.getMessage().getHeaders().get("form", Form.class); if ((form.formName == null)||(form.formName.indexOf("坏") > -1)) { returnValue = false; } else { returnValue = true; } System.out.println(form.toString()+" is "+returnValue); return returnValue; } }

还有四件套的最后一个EventConfig：

@WithStateMachine(id="complexFormMachine") public class ComplexFormEventConfig { private Logger logger = LoggerFactory.getLogger(getClass()); /** * 当前状态BLANK_FORM */ @OnTransition(target = "BLANK_FORM") public void create() { logger.info("---空白复杂表单---"); } @OnTransition(source = "BLANK_FORM", target = "FULL_FORM") public void write(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form")); logger.info("---填写完复杂表单---"); } @OnTransition(source = "FULL_FORM", target = "CHECK_CHOICE") public void check(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---校验复杂表单---"); } //不会执行 @OnTransition(source = "CHECK_CHOICE", target = "CONFIRM_FORM") public void check2confirm(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---校验表单到待提交表单(choice true)---"); } //不会执行 @OnTransition(source = "CHECK_CHOICE", target = "DEAL_FORM") public void check2deal(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---校验表单到待提交表单(choice false)---"); } @OnTransition(source = "DEAL_FORM", target = "DEAL_CHOICE") public void deal(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---处理复杂表单---"); } //不会执行 @OnTransition(source = "DEAL_CHOICE", target = "FAILED_FORM") public void deal2fail(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---处理复杂表单失败(choice false)---"); } //不会执行 @OnTransition(source = "DEAL_CHOICE", target = "FULL_FORM") public void deal2full(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---处理复杂表单到重新填写表单(choice true)---"); } /** * CONFIRM_FORM->SUCCESS_FORM 执行的动作 */ @OnTransition(source = "CONFIRM_FORM", target = "SUCCESS_FORM") public void submit(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---表单提交成功---"); } }

这边的代码没有任何特别的地方，唯一需要需要注意的是我标注的不会执行的这几个方法。因为在choice判断的时候，从一个状态转变到另外一个状态时，是不会在eventConfig触发方法的，比如这个方法：

//不会执行 @OnTransition(source = "CHECK_CHOICE", target = "CONFIRM_FORM") public void check2confirm(Message<ComplexFormEvents> message) { System.out.println("传递的参数：" + message.getHeaders().get("form").toString()); logger.info("---校验表单到待提交表单(choice true)---"); }

我定义了如果用户从CHECK_CHOICE状态如果判断后变成CONFIRM_FORM，执行check2confirm方法，但可惜，状态的确变化了，但这个方法不会执行，只有在做判断的时候会执行ComplexFormCheckChoiceGuard的evaluate()。这就有个问题，在实际运行中，我们的确会需要在choice做出判断状态改变的时候要做些业务处理，比如表单check成功后需要通知后续人员来处理什么的，这该怎么办呢？

简单除暴第一招，直接在gurad里面处理。这种方法其实没有任何问题，因为既然判断的业务代码在这里面，我们把判断完成后需要做的事也在这里写完不就行了。但是，本着无关的业务能解耦就解耦的原则，我们还有一个办法漂亮解耦第二招，写个action。下面介绍下这个action。

action，看这个名字就知道是要搞事情的，之前我们把业务代码都是写到eventConfig的方法里面，但其实可以不怎么干，我们完全可以在每个状态变化的时候独立写一个action，这样的话就能做到业务的互不打扰。不如下面这段：

.withChoice() .source(ComplexFormStates.CHECK_CHOICE) .first(ComplexFormStates.CONFIRM_FORM, new ComplexFormCheckChoiceGuard(),new ComplexFormChoiceAction()) .last(ComplexFormStates.DEAL_FORM,new ComplexFormChoiceAction()) .and()

这是builder里面的代码片段，我们直接把action插入进来，在状态变化的时候就能在action里面处理了，下面是这个action

的代码：

public class ComplexFormChoiceAction implements Action<ComplexFormStates, ComplexFormEvents> { @Override public void execute(StateContext<ComplexFormStates, ComplexFormEvents> context) { System.out.println("into ComplexFormChoiceAction"); Form form = context.getMessage().getHeaders().get("form", Form.class); System.out.println(form); System.out.println(context.getStateMachine().getState()); } }

这里面只有一个execute的方法，简单明了，我们需要的参数通过context传递，其实还是message，这样的话，不同业务用不同的action就行了，我们再回头看builder里面插入action的地方：

.first(ComplexFormStates.CONFIRM_FORM, new ComplexFormCheckChoiceGuard(),new ComplexFormChoiceAction(),new ComplexFormChoiceAction())

action可以多个插入，也就是有多少单独的业务需要在这里面处理都行，其实回过头来，不止在withChoice()里面可以，之前的withExternal()也是可以的，看代码：

.withExternal() .source(ComplexFormStates.FULL_FORM).target(ComplexFormStates.CHECK_CHOICE) .event(ComplexFormEvents.CHECK) .action(new ComplexFormChoiceAction(),new ComplexFormChoiceAction()) .guard(new ComplexFormCheckChoiceGuard()) .and()

action可以插入多个，但guard在这里恢复了本来的作用，保护状态变化，所以只能插入一个。

3、在controller里面看结果

最后，我们还是需要看下运行的结果，我准备了三个流程：

check成功，成为SUCCESS_FORMcheck失败，deal成功，回到FULL_FORMcheck失败，deal失败，成为FAILED_FORM

对应的是form1，form2和form3，看代码：

@Autowired private ComplexFormStateMachineBuilder complexFormStateMachineBuilder; ...... @RequestMapping("/testComplexFormState") public void testComplexFormState() throws Exception { StateMachine<ComplexFormStates, ComplexFormEvents> stateMachine = complexFormStateMachineBuilder.build(beanFactory); System.out.println(stateMachine.getId()); Form form1 = new Form(); form1.setId("111"); form1.setFormName(null); Form form2 = new Form(); form2.setId("222"); form2.setFormName("好的表单"); Form form3 = new Form(); form3.setId("333"); form3.setFormName(null); // 创建流程 System.out.println("-------------------form1------------------"); stateMachine.start(); Message message = MessageBuilder.withPayload(ComplexFormEvents.WRITE).setHeader("form", form1).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form1).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.DEAL).setHeader("form", form1).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form1).build(); stateMachine.sendEvent(message); System.out.println("最终状态：" + stateMachine.getState().getId()); System.out.println("-------------------form2------------------"); stateMachine = complexFormStateMachineBuilder.build(beanFactory); stateMachine.start(); message = MessageBuilder.withPayload(ComplexFormEvents.WRITE).setHeader("form", form2).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form2).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.DEAL).setHeader("form", form2).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form2).build(); stateMachine.sendEvent(message); System.out.println("最终状态：" + stateMachine.getState().getId()); System.out.println("-------------------form3------------------"); stateMachine = complexFormStateMachineBuilder.build(beanFactory); stateMachine.start(); message = MessageBuilder.withPayload(ComplexFormEvents.WRITE).setHeader("form", form3).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form3).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); form3.setFormName("好的表单"); message = MessageBuilder.withPayload(ComplexFormEvents.DEAL).setHeader("form", form3).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form3).build(); stateMachine.sendEvent(message); message = MessageBuilder.withPayload(ComplexFormEvents.CHECK).setHeader("form", form3).build(); stateMachine.sendEvent(message); System.out.println("当前状态：" + stateMachine.getState().getId()); message = MessageBuilder.withPayload(ComplexFormEvents.SUBMIT).setHeader("form", form3).build(); stateMachine.sendEvent(message); System.out.println("最终状态：" + stateMachine.getState().getId()); } ......

看console的结果就知道正确与否

构建复杂表单状态机 complexFormMachine -------------------form1------------------ 2019-05-13 18:07:19.364 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---空白复杂表单--- 2019-05-13 18:07:19.368 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started org.springframework.statemachine.support.DefaultStateMachineExecutor@16603576 2019-05-13 18:07:19.369 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started CONFIRM_FORM BLANK_FORM FAILED_FORM FULL_FORM SUCCESS_FORM DEAL_FORM DEAL_CHOICE CHECK_CHOICE / BLANK_FORM / uuid=2aa87c74-dd28-4790-9722-d04657eaf046 / id=complexFormMachine 传递的参数：Form [id=111, formName=null] 2019-05-13 18:07:19.381 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---填写完复杂表单--- 当前状态：FULL_FORM 传递的参数：Form [id=111, formName=null] 2019-05-13 18:07:19.386 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单--- ComplexFormCheckChoiceGuard!!!!!!!!!!!!! Form [id=111, formName=null] is false into ComplexFormChoiceAction Form [id=111, formName=null] ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=381700599, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]] 当前状态：DEAL_FORM 传递的参数：Form [id=111, formName=null] 2019-05-13 18:07:19.389 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---处理复杂表单--- ComplexFormDealChoiceGuard!!!!!!!!!!!!! Form [id=111, formName=null] is false into ComplexFormChoiceAction Form [id=111, formName=null] ObjectState [getIds()=[DEAL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=980487842, toString()=AbstractState [id=DEAL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]] 当前状态：FAILED_FORM 最终状态：FAILED_FORM -------------------form2------------------ 构建复杂表单状态机 2019-05-13 18:07:19.394 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---空白复杂表单--- 2019-05-13 18:07:19.394 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started org.springframework.statemachine.support.DefaultStateMachineExecutor@51adbaad 2019-05-13 18:07:19.394 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started CONFIRM_FORM BLANK_FORM FAILED_FORM FULL_FORM SUCCESS_FORM DEAL_FORM DEAL_CHOICE CHECK_CHOICE / BLANK_FORM / uuid=fa133ea8-bf48-437e-ae35-dc7aa616a23c / id=complexFormMachine 传递的参数：Form [id=222, formName=好的表单] 2019-05-13 18:07:19.395 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---填写完复杂表单--- 当前状态：FULL_FORM 传递的参数：Form [id=222, formName=好的表单] 2019-05-13 18:07:19.396 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单--- ComplexFormCheckChoiceGuard!!!!!!!!!!!!! Form [id=222, formName=好的表单] is true into ComplexFormChoiceAction Form [id=222, formName=好的表单] ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=249611509, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]] 当前状态：CONFIRM_FORM 当前状态：CONFIRM_FORM 传递的参数：Form [id=222, formName=好的表单] 2019-05-13 18:07:19.399 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---表单提交成功--- 最终状态：SUCCESS_FORM -------------------form3------------------ 构建复杂表单状态机 2019-05-13 18:07:19.404 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---空白复杂表单--- 2019-05-13 18:07:19.405 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started org.springframework.statemachine.support.DefaultStateMachineExecutor@6f12d1a 2019-05-13 18:07:19.406 INFO 6188 --- [nio-9991-exec-1] o.s.s.support.LifecycleObjectSupport : started CONFIRM_FORM BLANK_FORM FAILED_FORM FULL_FORM SUCCESS_FORM DEAL_FORM DEAL_CHOICE CHECK_CHOICE / BLANK_FORM / uuid=03e8c891-eedc-4922-811c-ab375a1e70ae / id=complexFormMachine 传递的参数：Form [id=333, formName=null] 2019-05-13 18:07:19.409 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---填写完复杂表单--- 当前状态：FULL_FORM 传递的参数：Form [id=333, formName=null] 2019-05-13 18:07:19.410 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单--- ComplexFormCheckChoiceGuard!!!!!!!!!!!!! Form [id=333, formName=null] is false into ComplexFormChoiceAction Form [id=333, formName=null] ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=608638875, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]] 当前状态：DEAL_FORM 传递的参数：Form [id=333, formName=好的表单] 2019-05-13 18:07:19.412 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---处理复杂表单--- ComplexFormDealChoiceGuard!!!!!!!!!!!!! Form [id=333, formName=好的表单] is true into ComplexFormChoiceAction Form [id=333, formName=好的表单] ObjectState [getIds()=[DEAL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=1203626264, toString()=AbstractState [id=DEAL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]] 当前状态：FULL_FORM 传递的参数：Form [id=333, formName=好的表单] 2019-05-13 18:07:19.413 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---校验复杂表单--- ComplexFormCheckChoiceGuard!!!!!!!!!!!!! Form [id=333, formName=好的表单] is true into ComplexFormChoiceAction Form [id=333, formName=好的表单] ObjectState [getIds()=[FULL_FORM], getClass()=class org.springframework.statemachine.state.ObjectState, hashCode()=608638875, toString()=AbstractState [id=FULL_FORM, pseudoState=null, deferred=[], entryActions=[], exitActions=[], stateActions=[], regions=[], submachine=null]] 当前状态：CONFIRM_FORM 传递的参数：Form [id=333, formName=好的表单] 2019-05-13 18:07:19.415 INFO 6188 --- [nio-9991-exec-1] tConfig$$EnhancerBySpringCGLIB$$37df7571 : ---表单提交成功--- 最终状态：SUCCESS_FORM

大家可以跑一下，对照状态机的流程图，看下结果。

4、继续废话

其实spring statemachine写到这里，基本上已经可以上手去做企业开发了。当然，spring statemachine里面还有很多其他的东西，大部分是处理复杂状态机流程的，以后有机会我们再展开讲。

源代码地址

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