activiti全局监听器

全局监听器主要使用的场景就是监控这个流程的启动和结束。流程开始的时候可以监控，流程结束的时候也可以监控

监听器的接口

public interface ActivitiEventListener { /**当时间被执行时调用该方法*/ void onEvent(ActivitiEvent event); /** * @author 郑小康 * 这个是onEvent执行失败之后进行的处理 * * 如果是true则返回onEvent执行失败的异常 * * 如果是false则忽略这个异常 * */ boolean isFailOnException(); }

初始化所有监听器

将所有全局监听器和类型监听器给加入到当前eventListeners里面，这里只是初始化过程

/** * @author 郑小康 * * 事件监听器分为两种 * * 1.如果eventDispatcher为空，则实例化ActivitiEventDispatcherImpl * * 2.设置eventDispatcher的状态为enableEventDispatcher，其值为true 默认支持事件转发 * * 3.遍历当前流程实例所有的eventListeners监听器,将其添加到eventDispatcher * * 4.遍历所有typedEventListeners 以entry为key进行添加 * 在cfg.xml文件定义： * <property name="typedEventListeners"> * <map> * <entry key="JOB_EXECUTION_SUCCESS,JOB_EXECUTION_FAILURE" > * <list> * <bean class="org.activiti.engine.example.MyJobEventListener" /> * </list> * </entry> * </map> * </property> * */ public void initEventDispatcher() { if (this.eventDispatcher == null) { this.eventDispatcher = new ActivitiEventDispatcherImpl(); } this.eventDispatcher.setEnabled(enableEventDispatcher); if (eventListeners != null) { for (ActivitiEventListener listenerToAdd : eventListeners) { this.eventDispatcher.addEventListener(listenerToAdd); } } if (typedEventListeners != null) { for (Entry<String, List<ActivitiEventListener>> listenersToAdd : typedEventListeners.entrySet()) { // Extract types from the given string ActivitiEventType[] types = ActivitiEventType.getTypesFromString(listenersToAdd.getKey()); for (ActivitiEventListener listenerToAdd : listenersToAdd.getValue()) { this.eventDispatcher.addEventListener(listenerToAdd, types); } } } }

初始化监听器配置过程

   其实在流程实例中注入相对应的属性bean

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="driverClassName"> <value>com.mysql.jdbc.Driver</value> </property> <property name="url"> <value>jdbc:mysql://127.0.0.1:3306/activiti?useUnicode=true&characterEncoding=UTF-8 </value> </property> <property name="username"> <value>root</value> </property> <property name="password" value="fadp" /> </bean> <bean id="processEngine1" name="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneProcessEngineConfiguration"> <property name="dataSource" ref="dataSource" /> <property name="databaseSchemaUpdate" value="true" /> <property name="eventListeners"> <list> <bean class="com.event.MyEventListener" /> </list> </property> </bean> </beans>

监听器在流程实例启动时候的应用

       在构建流程实例的时候，会构建一个流程实例，在器最后会构建一个引擎启动时间，调用所有监听器的onEvent 方法

public ProcessEngineImpl(ProcessEngineConfigurationImpl processEngineConfiguration) { ....... //调用时间转发器,构建一个事件实例ActivitiEvent类型为ENGINE_CREATED,然后进行事件转发 processEngineConfiguration.getEventDispatcher().dispatchEvent(ActivitiEventBuilder.createGlobalEvent(ActivitiEventType.ENGINE_CREATED)); }

/** * 1.enabled判断,默认为true进行事件转发 * * 2.FIXME:尚未理解 * */ @Override public void dispatchEvent(ActivitiEvent event) { if (enabled) { eventSupport.dispatchEvent(event); } if (event.getType() == ActivitiEventType.ENTITY_DELETED && event instanceof ActivitiEntityEvent) { ActivitiEntityEvent entityEvent = (ActivitiEntityEvent) event; if (entityEvent.getEntity() instanceof ProcessDefinition) { // process definition deleted event doesn't need to be dispatched to event listeners return; } } CommandContext commandContext = Context.getCommandContext(); if (commandContext != null) { BpmnModel bpmnModel = extractBpmnModelFromEvent(event); if (bpmnModel != null) { ((ActivitiEventSupport) bpmnModel.getEventSupport()).dispatchEvent(event); } } } /** * @author 郑小康 * * 1.对当前转化的事件做非空校验 * * 2.转化所有全局事件监听器 * * 3.获取跟当前事件类型相同的事件监听器,并进行事件转化进行执行 * * */ public void dispatchEvent(ActivitiEvent event) { if (event == null) { throw new ActivitiIllegalArgumentException("Event cannot be null."); } if (event.getType() == null) { throw new ActivitiIllegalArgumentException("Event type cannot be null."); } //执行所有全局事件监听器 if (!eventListeners.isEmpty()) { for (ActivitiEventListener listener : eventListeners) { dispatchEvent(event, listener); } } //获取跟当前事件类型相同的事件监听器,并进行事件转化进行执行 List<ActivitiEventListener> typed = typedListeners.get(event.getType()); if (typed != null && !typed.isEmpty()) { for (ActivitiEventListener listener : typed) { dispatchEvent(event, listener); } } }

测试

@Test public void getDefaultProcessEngine() { ProcessEngineConfiguration pec = ProcessEngineConfiguration.createProcessEngineConfigurationFromResource("com/event/activiti.cfg.xml"); ProcessEngine pe1 = pec.buildProcessEngine(); }

测试结果

Event received: ENGINE_CREATED

       其中还有一种动态加载监听器的过程，通过第一个流程实例获取监听器的集合，进行添加，在第二个流程实例中就可以这样用了，为什么是这样呢，因为spring获取bean是单例模式，监听器引用类型指向的是同一个变量，使用过程如下：

@Before public void init() { processEngine = ProcessEngineConfiguration .createProcessEngineConfigurationFromResource( "com/activiti_study/ch24/activiti1.cfg.xml") .buildProcessEngine(); repositoryService = processEngine.getRepositoryService(); activitiEventDispatcher = ((ProcessEngineConfigurationImpl) processEngine .getProcessEngineConfiguration()).getEventDispatcher(); } @Test public void testAddEventListener() { ShareniuTaskEventListener2 shareniuTaskEventListener2 = new ShareniuTaskEventListener2(); activitiEventDispatcher.addEventListener(shareniuTaskEventListener2); ProcessEngine pe = ProcessEngines.getDefaultProcessEngine(); System.out.println(pe); processEngine = ProcessEngineConfiguration .createProcessEngineConfigurationFromResource( "com/activiti_study/ch24/activiti1.cfg.xml") .buildProcessEngine(); }