Activiti6.0流程引擎学习——(21)activiti的流程运行控制服务（RuntimeService）【2】

接着上篇继续介绍activiti的流程运行控制服务。

流程实例与执行流：

1、流程实例（ProcessInstance）表示一次工作流业务的数据实体；

2、执行流（Execution）表示流程实例汇总具体的执行路径；

3、流程实例接口（ProcessInstance）继承了执行流（Execution），流程实例在执行流的基础上扩展了一些其他系列的操作。

 

流程触发：

1、使用trigger触发ReceiveTask节点，当流程执行到这个Task节点的时候就会暂停下来，等待需要接受的事件去执行；

2、触发信号捕获事件signalEventReceived，当只有获取这个信号以后才能继续执行；

3、触发消息捕获事件messageEventReceived，只有捕获到某些消息后才能继续执行。

注：这里触发信号与触发消息非常相似，但是信号是可以全局发送信号，消息只能针对某个流程实例发送消息。

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接下来我们来测试一下：

一、流程触发trigger

首先只是为了测试，所以我们使用一个简单的流程图：

然后用代码演示一下执行效果：

先要定义并且设计如上一样的流程图，创建my-process-trigger.bpmn20.xml流程文件：

my-process-trigger.bpmn20.xml文件中内容如下：

然后在上一篇创建的RuntimeServiceTest测试类中新增测试函数：

    /**
     * 流程触发trigger
     */
    @Test
    @org.activiti.engine.test.Deployment(resources = "my-process-trigger.bpmn20.xml")
    public void testTrigger(){
        RuntimeService runtimeService = activitiRule.getRuntimeService();
        ProcessInstance processInstance = runtimeService
                .startProcessInstanceByKey("my-process");//通过流程图中的来启动流程

        Execution execution = runtimeService.createExecutionQuery()
                .activityId("someTask").singleResult();   //获取执行流对象，someTask是其中事件的id
        LOGGER.info("execution = [{}]" , execution);

        runtimeService.trigger(execution.getId());   //获取这个的id来触发执行
        execution = runtimeService.createExecutionQuery()
                .activityId("someTask").singleResult();     //重新获取someTask
        LOGGER.info("execution = [{}]" , execution);    //重新打印
    }

测试结果：

Loading XML bean definitions from class path resource [activiti.cfg.xml]
Activiti 5 compatibility handler implementation not found or error during instantiation : org.activiti.compatibility.DefaultActiviti5CompatibilityHandler. Activiti 5 backwards compatibility disabled.
performing create on engine with resource org/activiti/db/create/activiti.h2.create.engine.sql
performing create on history with resource org/activiti/db/create/activiti.h2.create.history.sql
performing create on identity with resource org/activiti/db/create/activiti.h2.create.identity.sql
ProcessEngine default created
execution = [Execution[ id '5' ] - activity 'someTask - parent '4']
execution = [null]

可以看到我们第一次输出execution时可以获取到执行流对象 Execution[ id '5' ] - activity 'someTask - parent '4'。当触发信号发出去以后，流程执行过去则第二次输出execution时这个执行对象就已经没有了，也就是后面的null。

 

二、流程触发Signal信号事件

这里使用流程图如下：

创建my-process-signal-received.bpmn20.xml流程文件，其中xml流程文件内容：

在RuntimeServiceTest测试类中新增测试函数：

    /**
     * 测试流程触发的 signalEventReceived  信号捕获
     */
    @Test
    @org.activiti.engine.test.Deployment(resources = "my-process-signal-received.bpmn20.xml")
    public void testSignalEventReceived(){
        RuntimeService runtimeService = activitiRule.getRuntimeService();
        ProcessInstance processInstance = runtimeService
                .startProcessInstanceByKey("my-process");//通过流程图中的来启动流程

        Execution execution = runtimeService.createExecutionQuery()
                .signalEventSubscriptionName("my-signal").singleResult();   //获取执行流对象，my-signal是其中信号
        LOGGER.info("execution = [{}]" , execution);

        //来触发我们定义的信号,发出一个my-signal的信号，若不是这个信号则下面输出还停留在signal-received这一步
        runtimeService.signalEventReceived("my-signal");


        execution = runtimeService.createExecutionQuery()
                .signalEventSubscriptionName("my-signal").singleResult();
        LOGGER.info("execution = [{}]" , execution);    //重新打印
    }

输出结果：

Loading XML bean definitions from class path resource [activiti.cfg.xml]
Activiti 5 compatibility handler implementation not found or error during instantiation : org.activiti.compatibility.DefaultActiviti5CompatibilityHandler. Activiti 5 backwards compatibility disabled.
performing create on engine with resource org/activiti/db/create/activiti.h2.create.engine.sql
performing create on history with resource org/activiti/db/create/activiti.h2.create.history.sql
performing create on identity with resource org/activiti/db/create/activiti.h2.create.identity.sql
ProcessEngine default created
execution = [Execution[ id '5' ] - activity 'signal-received - parent '4']
execution = [null]

 

三、流程触发messageEventReceived

信号与具体流程实例没有关系，但是这里的消息必须指定流程执行对象的ID才能继续执行。

测试流程图如下：

创建my-process-message-received.bpmn20.xml流程文件，xml流程文件内容：

在RuntimeServiceTest测试类中新增测试函数：

     /**
     * 测试事件触发的 messageEventReceived  信号捕获
     */
    @Test
    @org.activiti.engine.test.Deployment(resources = "my-process-message-received.bpmn20.xml")
    public void testMessageEventReceived(){
        RuntimeService runtimeService = activitiRule.getRuntimeService();
        ProcessInstance processInstance = runtimeService
                .startProcessInstanceByKey("my-process");//通过流程图中的来启动流程

        Execution execution = runtimeService.createExecutionQuery()
                .messageEventSubscriptionName("my-message").singleResult();   //获取执行流对象，my-message是消息
        LOGGER.info("execution = [{}]" , execution);

        runtimeService.messageEventReceived("my-message",execution.getId());   //将流程执行ID作为参数传进去


        execution = runtimeService.createExecutionQuery()
                .messageEventSubscriptionName("my-message").singleResult();
        LOGGER.info("execution = [{}]" , execution);    //重新打印
    }

输出结果：

Loading XML bean definitions from class path resource [activiti.cfg.xml]
Activiti 5 compatibility handler implementation not found or error during instantiation : org.activiti.compatibility.DefaultActiviti5CompatibilityHandler. Activiti 5 backwards compatibility disabled.
performing create on engine with resource org/activiti/db/create/activiti.h2.create.engine.sql
performing create on history with resource org/activiti/db/create/activiti.h2.create.history.sql
performing create on identity with resource org/activiti/db/create/activiti.h2.create.identity.sql
ProcessEngine default created
execution = [Execution[ id '5' ] - activity 'message-received - parent '4']
execution = [null]

 

四、基于message启动流程

创建my-process-message.bpmn20.xml流程文件，其中流程内容如下：

RuntimeServiceTest测试类中的测试函数：

    /**
     * 基于message启动流程
     */
    @Test
    @org.activiti.engine.test.Deployment(resources = "my-process-message.bpmn20.xml")
    public void testMessageStart(){
        RuntimeService runtimeService = activitiRule.getRuntimeService();
        ProcessInstance processInstance = runtimeService
                .startProcessInstanceByMessage("my-message");  //通过流程图中的  来启动流程

        LOGGER.info("processInstance = [{}]", processInstance);
    }

输出结果：

可以看到基于message也可以正常启动流程实例。

基于key启动与message启动的区别？

基于key启动更为简洁，基于message启动则有点繁琐，需要在流程定义文件里面定义一个message标签。并且得到的ProcessInstance[5]，key则是ProcessInstance[4]。因为基于message启动会在数据库的表中插入一条记录，所以就变成了5。启动过程是根据message信号从事件订阅中找到订阅这个信号的id，最后找到流程定义的key然后启动。