1. Activiti 多实例

多实例节点是在业务流程中定义重复环节的一种方式

从开发角度讲, 多实例类似于循环, 可以根据给定的集合, 为每个元素执行一个环境甚至一个子流程, 既可以顺序依次执行也可以并发同步执行.

多实例是在一个普通节点上添加额外的属性定义, 这样被多实例修饰的节点就会执行多次, 在 BPMN 规范中, 下面的节点都可以成为一个多实例节点:

UserTask
Script Task
Java Service Task
Web Service Task
Business Rule Task
Email Task
Manual Task
Receive Task
Sub-Process
Call Activity

每个上级流程为每个实例创建分支的时候都要提供如下变量:

nrOfInstances: 实例总数
nrOfActiveInstances: 当前活动的实例数量, 对于顺序执行的多实例, 该值始终为1
nrOfCompletedInstances: 已经完成的实例数量
loopCounter: 当前实例所在循环的索引值, 其他实例不可见, 不会保存到流程实例级别.

可以通过 execution.getVariable(String key) 方法获得这些变量

1.1. `isSequential`

表示节点时顺序执行还是并行执行, 默认为 false, 表示并行执行

1.2. 指定实例数量

实例的数量会在进入节点时进行计算, 但也可以直接指定

<multiInstanceLoopCharacteristics isSequential="false">
    <!-- 可以使用loopCardinality子元素直接指定一个数字 -->
    <loopCardinality>5</loopCardinality>
    <!-- 也可以使用结果为整数的表达式 -->
    <loopCardinality>${nrOfOrders-nrOfCancellations}</loopCardinality>
</multiInstanceLoopCharacteristics>

1.3. 接收并遍历集合

除此之外还可以通过 loopDataInputRef 元素设置一个类型为集合的流程变量名, 对于集合中的每个元素都会创建一个实例, 也可以通过 inputDataItem 子元素指定集合

<userTask id="someTask" name="Activiti is awesome!" activiti:assignee="${user}">
    <multiInstanceLoopCharacteristics isSequential="false">
        <loopDataInputRef>userList</loopDataInputRef>
        <inputDataItem name="user"/>
    </multiInstanceLoopCharacteristics>
</userTask>

loopDataInputRef 中的 userList 表示需要遍历的元素列表
inputDataItem 中的 user 表示每个分支都会拥有一个名为 user 的流程变量, 这个变量会包含集合中的对应元素, 在例子中用来设置用户任务的办理者, 也就是说 userTask 中的 activiti:assignee 属性的值需要和 inputDataItem 一致.

此外, 上述的变量名存在如下缺点:

名称复杂
BPMN2.0 规定不能该节点不能包含表达式

Activiti 通过 multiInstanceCharacteristics 中设置 collection 和 elementVariable 属性来解决这个问题:

1
2
3

<userTask id="someTask" name="Activiti is awesome!" activiti:assignee="${user}">
    <multiInstanceLoopCharacteristics isSequential="false" activiti:collection="${userList}" activiti:elementVariable="user"/>
</userTask>

二者实现的功能是相同的, 不过后者可以支持表达式, 这是我们动态配置用户任务属性的重要功能

1.4. 结束条件

多实例节点默认会在所有节点完成后结束, 也可以指定一个表达式在每个实例结束时执行, 如果表达式返回 true, 所有其他的实例都会销毁, 多实例节点也会结束, 流程会继续执行.

<userTask id="someTask" name="Activiti is awesome!" activiti:assignee="${user}">
    <multiInstanceLoopCharacteristics isSequential="false" activiti:collection="${userList}" activiti:elementVariable="user">
        <!-- 如果有 60% 的任务完成时, 其他任务会被删除, 流程继续进行 -->
        <completionCondition>${nrOfCompletedInstances/nrOfInstances >= 0.6}</completionCondition>
    </multiInstanceLoopCharacteristics>
</userTask>

2. 会签逻辑

经过以上对 Activiti 多实例的介绍可知, 实现会签功能几个重要的点在于:

利用多实例完成动态实例的创建
根据业务设置合适的结束条件

2.1. 流程定义

2.1.1. XML 格式

<process id="my-process">
    <startEvent id="start"/>
    <sequenceFlow id="flow1" sourceRef="start" targetRef="someTask" />
    <userTask id="someTask" name="Activiti is awesome!" activiti:assignee="${user}">
        <multiInstanceLoopCharacteristics isSequential="false" activiti:collection="${userList}" activiti:elementVariable="user"/>
    </userTask>
    <sequenceFlow id="flow2" sourceRef="someTask" targetRef="end"/>
    <endEvent id="end" />
</process>

2.1.2. BpmnModel 模型

用到的测试类:

@Slf4j
@Component
public class UsersBean implements Serializable {

    public List<String> getUsers(String userId) {
        log.info("userId: {}", userId);
        return Arrays.asList(userId + "1", userId + "2", userId + "3");
    }
}

@Test
public void testExclusionGatewayModel() {
    BpmnModel bpmnModel = new BpmnModel();
    Process process = new Process();
    process.setId("my-process");
    StartEvent startEvent = new StartEvent();
    startEvent.setId("startEvent");
    UserTask someTask = new UserTask();
    someTask.setId("someTask");
    someTask.setName("Activiti is awesome!");
    someTask.setAssignee("${user}");
    MultiInstanceLoopCharacteristics multiInstanceLoopCharacteristics = new MultiInstanceLoopCharacteristics();
    multiInstanceLoopCharacteristics.setSequential(false);
    multiInstanceLoopCharacteristics.setInputDataItem("${usersBean.getUsers(name)}");
    multiInstanceLoopCharacteristics.setElementVariable("user");
    multiInstanceLoopCharacteristics.setCompletionCondition("${nrOfCompletedInstances > 0}");
    someTask.setLoopCharacteristics(multiInstanceLoopCharacteristics);
    EndEvent endEvent = new EndEvent();
    endEvent.setId("endEvent");
    SequenceFlow flow1 = createSequence("startEvent", "someTask", "flow1", "flow1", null);
    SequenceFlow flow2 = createSequence("someTask", "endEvent", "flow2", "flow2", null);
    process.addFlowElement(startEvent);
    process.addFlowElement(someTask);
    process.addFlowElement(endEvent);
    process.addFlowElement(flow1);
    process.addFlowElement(flow2);
    bpmnModel.addProcess(process);
    
    
    // client
    Deployment deployment = activitiRule.getRepositoryService().createDeployment()
            .addBpmnModel("bpmn", bpmnModel)
            .deploy();
    log.info("deployment: {}", ToStringBuilder.reflectionToString(deployment, ToStringStyle.JSON_STYLE));
    Map<String, Object> map = new HashMap<>();
    map.put("usersBean", usersBean);
    map.put("name", "wk");
    
    ProcessInstance processInstance = activitiRule.getRuntimeService().startProcessInstanceByKey("my-process", map);
    log.info("processInstance: {}", ToStringBuilder.reflectionToString(processInstance, ToStringStyle.JSON_STYLE));
    List<Task> taskList = activitiRule.getTaskService().createTaskQuery().list();
    log.info("当前 taskList 数量: {}", taskList.size());
    for (Task task : taskList) {
        log.info("task: {}", ToStringBuilder.reflectionToString(task, ToStringStyle.JSON_STYLE));
    }
    activitiRule.getTaskService().complete(taskList.get(0).getId());
    log.info("其中一个节点完成审批");
    taskList = activitiRule.getTaskService().createTaskQuery().list();
    log.info("第一个节点审批完成后 taskList 数量: {}", taskList.size());
    for (Task task : taskList) {
        log.info("第一个节点审批完成后 task: {}", ToStringBuilder.reflectionToString(task, ToStringStyle.JSON_STYLE));
    }
}

2.1.3. 日志输出

09:55:17,517 [main] INFO  org.destiny.activiti.GatewayExpressSpringTest  - processInstance: {"currentFlowElement":null,"currentActivitiListener":null,"processInstance":"ProcessInstance[4]","parent":null,"executions":[Multi instance root execution[ id '8' ] - activity 'someTask - parent '4'],"superExecution":null,"subProcessInstance":null,"tenantId":"","name":null,"description":null,"localizedName":null,"localizedDescription":null,"lockTime":null,"isActive":true,"isScope":true,"isConcurrent":false,"isEnded":false,"isEventScope":false,"isMultiInstanceRoot":false,"isCountEnabled":false,"eventName":null,"eventSubscriptions":[],"jobs":[],"timerJobs":[],"tasks":[],"identityLinks":[IdentityLinkEntity[id=24, type=participant, userId=wk1, processInstanceId=4], IdentityLinkEntity[id=27, type=participant, userId=wk2, processInstanceId=4], IdentityLinkEntity[id=30, type=participant, userId=wk3, processInstanceId=4]],"deleteReason":null,"suspensionState":1,"startUserId":null,"startTime":"Sun Dec 16 21:55:17 CST 2018","eventSubscriptionCount":0,"taskCount":0,"jobCount":0,"timerJobCount":0,"suspendedJobCount":0,"deadLetterJobCount":0,"variableCount":0,"identityLinkCount":0,"processDefinitionId":"my-process:1:3","processDefinitionKey":"my-process","processDefinitionName":null,"processDefinitionVersion":1,"deploymentId":null,"activityId":null,"activityName":null,"processInstanceId":"4","businessKey":null,"parentId":null,"superExecutionId":null,"rootProcessInstanceId":"4","rootProcessInstance":null,"forcedUpdate":false,"queryVariables":null,"isDeleted":false,"variableInstances":{usersBean=VariableInstanceEntity[id=6, name=usersBean, type=serializable, byteArrayValueId=5]},"usedVariablesCache":{},"transientVariabes":null,"cachedElContext":null,"id":"4","revision":1,"isInserted":true,"isUpdated":false,"isDeleted":false}
09:59:03,449 [main] INFO  org.destiny.activiti.GatewayExpressSpringTest  - 当前 taskList 数量: 3
09:59:03,450 [main] INFO  org.destiny.activiti.GatewayExpressSpringTest  - task: {"owner":null,"assigneeUpdatedCount":1,"originalAssignee":null,"assignee":"wk1","delegationState":null,"parentTaskId":null,"name":"Activiti is awesome!","localizedName":null,"description":null,"localizedDescription":null,"priority":50,"createTime":"Sun Dec 16 21:59:03 CST 2018","dueDate":null,"suspensionState":1,"category":null,"isIdentityLinksInitialized":false,"taskIdentityLinkEntities":[],"executionId":"14","execution":null,"processInstanceId":"4","processInstance":null,"processDefinitionId":"my-process:1:3","taskDefinitionKey":"someTask","formKey":null,"isDeleted":false,"isCanceled":false,"eventName":null,"currentActivitiListener":null,"tenantId":"","queryVariables":null,"forcedUpdate":false,"claimTime":null,"variableInstances":null,"usedVariablesCache":{},"transientVariabes":null,"cachedElContext":null,"id":"24","revision":1,"isInserted":false,"isUpdated":false,"isDeleted":false}
09:59:03,450 [main] INFO  org.destiny.activiti.GatewayExpressSpringTest  - task: {"owner":null,"assigneeUpdatedCount":1,"originalAssignee":null,"assignee":"wk2","delegationState":null,"parentTaskId":null,"name":"Activiti is awesome!","localizedName":null,"description":null,"localizedDescription":null,"priority":50,"createTime":"Sun Dec 16 21:59:03 CST 2018","dueDate":null,"suspensionState":1,"category":null,"isIdentityLinksInitialized":false,"taskIdentityLinkEntities":[],"executionId":"15","execution":null,"processInstanceId":"4","processInstance":null,"processDefinitionId":"my-process:1:3","taskDefinitionKey":"someTask","formKey":null,"isDeleted":false,"isCanceled":false,"eventName":null,"currentActivitiListener":null,"tenantId":"","queryVariables":null,"forcedUpdate":false,"claimTime":null,"variableInstances":null,"usedVariablesCache":{},"transientVariabes":null,"cachedElContext":null,"id":"27","revision":1,"isInserted":false,"isUpdated":false,"isDeleted":false}
09:59:03,451 [main] INFO  org.destiny.activiti.GatewayExpressSpringTest  - task: {"owner":null,"assigneeUpdatedCount":1,"originalAssignee":null,"assignee":"wk3","delegationState":null,"parentTaskId":null,"name":"Activiti is awesome!","localizedName":null,"description":null,"localizedDescription":null,"priority":50,"createTime":"Sun Dec 16 21:59:03 CST 2018","dueDate":null,"suspensionState":1,"category":null,"isIdentityLinksInitialized":false,"taskIdentityLinkEntities":[],"executionId":"16","execution":null,"processInstanceId":"4","processInstance":null,"processDefinitionId":"my-process:1:3","taskDefinitionKey":"someTask","formKey":null,"isDeleted":false,"isCanceled":false,"eventName":null,"currentActivitiListener":null,"tenantId":"","queryVariables":null,"forcedUpdate":false,"claimTime":null,"variableInstances":null,"usedVariablesCache":{},"transientVariabes":null,"cachedElContext":null,"id":"30","revision":1,"isInserted":false,"isUpdated":false,"isDeleted":false}
...
09:55:17,585 [main] INFO  org.destiny.activiti.GatewayExpressSpringTest  - 其中一个节点完成审批
09:55:17,587 [main] INFO  org.destiny.activiti.GatewayExpressSpringTest  - 第一个节点审批完成后 taskList 数量: 0

Activiti(4)--多实例实现会签功能

1. Activiti 多实例

1.1. `isSequential`

1.2. 指定实例数量

1.3. 接收并遍历集合

1.4. 结束条件

2. 会签逻辑

2.1. 流程定义

2.1.1. XML 格式

2.1.2. BpmnModel 模型

2.1.3. 日志输出

3. 多实例任务节点完成自定义条件

1. Activiti 多实例

1.1. isSequential

1.2. 指定实例数量

1.3. 接收并遍历集合

1.4. 结束条件

2. 会签逻辑

2.1. 流程定义

2.1.1. XML 格式

2.1.2. BpmnModel 模型

2.1.3. 日志输出

3. 多实例任务节点完成自定义条件

1.1. `isSequential`