Liferay7 BPM門戶開發之2: BPMN 2.0 規范入門 （Activiti BPMN extensions）

Liferay最大的問題是BPM弱,如果做企業開發,BPM必不可少,所以直入主題,做個BPMN2入門.

本文參考地址：http://activiti.org/userguide/index.html#bpmnConstructs

BPMN 2.0中的重要概念：

• Events 事件 
• Sequence Flow 順序流
• Gateways 網關
• Tasks 任務
• Sub-Processes and Call Activities 子流程
• Transactions and Concurrency 事務並發
• Process Initiation Authorization 初始化認證
• Data objects 流程數據

其他相關項：

• Form properties 表單屬性
• External form rendering 外部表單集成

1、Events

1、1 Timer Event Definitions

由時間觸發的時間，用於

• start event
• intermediate event
• boundary event

必須有確切的一個元素，分別是：

timeDate

<timerEventDefinition> <timeDate>2011-03-11T12:13:14</timeDate> </timerEventDefinition>

在確切的時間點執行

timeDuration

<timerEventDefinition> <timeDuration>P10D</timeDuration> </timerEventDefinition>

 從最后一個任務完成后10天開始執行

timeCycle

<timerEventDefinition>
　　<timeCycle activiti:endDate="2015-02-25T16:42:11+00:00">R3/PT10H</timeCycle>
</timerEventDefinition>
或者變量形式：
<timerEventDefinition>
　　<timeCycle>R3/PT10H/${EndDate}</timeCycle>
</timerEventDefinition>

循環3次，間隔10小時

也可以使用cron expressions ：http://www.quartz-scheduler.org/documentation/

 

1.2 Signal Event Definitions

一個例子：https://github.com/chanjarster/activiti-learn/wiki/%E8%AF%A6%E8%A7%A3signal%20event

1.3 Message Event Definitions

想象一下，作為一個嵌入式的流程引擎（不是國內很多固化Hardcode式的流程引擎），Activiti關心的是實際從第三方應用系統接收的消息。這將是環境依賴和需要特定平台的活動。
比如：

• 連接到JMS（java消息服務）隊列
• 處理一個WebService
• REST請求
• MQ隊列的消息處理
• XMPP消息監聽
• ......

總之，消息是和應用程序相關聯的。

在您收到您的應用程序中的一個消息后，您必須決定該如何處理它。如果消息應該觸發一個新的流程實例的開始，process instance的啟動不應該使用runtimeService.startProcessInstanceByKey，在以下方法中選擇：

• ProcessInstance startProcessInstanceByMessage(String messageName);
• ProcessInstance startProcessInstanceByMessage(String messageName, Map<String, Object> processVariables);
• ProcessInstance startProcessInstanceByMessage(String messageName, String businessKey, Map<String, Object> processVariables);

<definitions id="definitions"
  xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
  xmlns:activiti="http://activiti.org/bpmn"
  targetNamespace="Examples"
  xmlns:tns="Examples">

  <message id="newInvoice" name="newInvoiceMessage" />
  <message id="payment" name="paymentMessage" />

  <process id="invoiceProcess">

    <startEvent id="messageStart" >
        <messageEventDefinition messageRef="newInvoice" />
    </startEvent>
    ...
    <intermediateCatchEvent id="paymentEvt" >
        <messageEventDefinition messageRef="payment" />
    </intermediateCatchEvent>
    ...
  </process>

</definitions>

有不同的方式來啟動事件，Message Event Definitions 就非常有用了

例如訂單可能來自call center ，也可以來自web shop

 

1.4 Start Events

開始事件總是捕捉型（Catching）的，比如一個消息接收，比如一個時間觸發，總是有指定的觸發。

<startEvent id="request" activiti:initiator="initiator" />

啟動：

try {
  identityService.setAuthenticatedUserId("bono");
  runtimeService.startProcessInstanceByKey("request");
} finally {
  identityService.setAuthenticatedUserId(null);
}

1.5 None Start Event

一個無啟動事件在技術上意味着啟動過程實例的觸發器是未指定的。而且沒有子元素節點。

一個有啟動表單的例子：

<startEvent id="request" activiti:formKey="org/activiti/examples/taskforms/request.form" />

圖形是一個空心圓：

 

1.6 Timer Start Event

時間啟動事件，是一個時鍾在中間的圓：

1.7 Boundary Events

邊界事件是catching型的，連接到一個活動（一個邊界事件永遠不會throwing）的事件。
這意味着，當活動正在運行時，事件正在偵聽某種類型的觸發器。當事件被捕獲時，該活動被中斷，順序流下行。

<boundaryEvent id="escalationTimer" cancelActivity="true" attachedToRef="firstLineSupport">
  <timerEventDefinition>
    <timeDuration>PT4H</timeDuration>
  </timerEventDefinition>
</boundaryEvent>

<boundaryEvent id="boundary" attachedToRef="task" cancelActivity="true">
          <messageEventDefinition messageRef="newCustomerMessage"/>
</boundaryEvent>

 

2. Sequence Flow

2.1 Conditional sequence flow

帶有UEL條件表達式的順序流

<sequenceFlow id="flow" sourceRef="theStart" targetRef="theTask">
  <conditionExpression xsi:type="tFormalExpression">
    <![CDATA[${order.price > 100 && order.price < 250}]]>
  </conditionExpression>
</sequenceFlow>

 

2.2 Default sequence flow

任務和網關都可以有默認順序流。

<exclusiveGateway id="exclusiveGw" name="Exclusive Gateway" default="flow2" />
<sequenceFlow id="flow1" sourceRef="exclusiveGw" targetRef="task1">
  <conditionExpression xsi:type="tFormalExpression">${conditionA}</conditionExpression>
</sequenceFlow>
<sequenceFlow id="flow2" sourceRef="exclusiveGw" targetRef="task2"/>
<sequenceFlow id="flow3" sourceRef="exclusiveGw" targetRef="task3">
  <conditionExpression xsi:type="tFormalExpression">${conditionB}</conditionExpression>
</sequenceFlow>

flow2就是默認順序流，當所有條件不滿足，則選擇默認順序流。

 

3 Gateways

 3.1 Exclusive Gateway

異或網關

     輸入：只要有一個活動節點到達該網關那么就觸發

     輸出：有多個輸出點時，只會觸發一個

<exclusiveGateway id="exclusiveGw" name="Exclusive Gateway" />

<sequenceFlow id="flow2" sourceRef="exclusiveGw" targetRef="theTask1">
  <conditionExpression xsi:type="tFormalExpression">${input == 1}</conditionExpression>
</sequenceFlow>

<sequenceFlow id="flow3" sourceRef="exclusiveGw" targetRef="theTask2">
  <conditionExpression xsi:type="tFormalExpression">${input == 2}</conditionExpression>
</sequenceFlow>

<sequenceFlow id="flow4" sourceRef="exclusiveGw" targetRef="theTask3">
  <conditionExpression xsi:type="tFormalExpression">${input == 3}</conditionExpression>
</sequenceFlow>

3.2 Parallel Gateway

並行網關，可以有多個輸入和輸出(fork, join or both) ，實現AND邏輯

輸入：該網關所有的輸入節點都必須完成后才能觸發該網關

輸出：該網關的所有輸出接點都將觸發（除非轉移條件不通過）

<startEvent id="theStart" />
<sequenceFlow id="flow1" sourceRef="theStart" targetRef="fork" />

<parallelGateway id="fork" />
<sequenceFlow sourceRef="fork" targetRef="receivePayment" />
<sequenceFlow sourceRef="fork" targetRef="shipOrder" />

<userTask id="receivePayment" name="Receive Payment" />
<sequenceFlow sourceRef="receivePayment" targetRef="join" />

<userTask id="shipOrder" name="Ship Order" />
<sequenceFlow sourceRef="shipOrder" targetRef="join" />

<parallelGateway id="join" />
<sequenceFlow sourceRef="join" targetRef="archiveOrder" />

<userTask id="archiveOrder" name="Archive Order" />
<sequenceFlow sourceRef="archiveOrder" targetRef="theEnd" />

<endEvent id="theEnd" />

 

 3.3 Inclusive Gateway

Inclusive包容網關（Xor輸入，And輸出）

     輸入：只要有一個活動節點到達該網關那么就觸發該網關（同XOR輸入）

     輸出：該網關的所有輸出接點都將觸發（除非轉移條件不通過）同AND輸出

 

<startEvent id="theStart" />
<sequenceFlow id="flow1" sourceRef="theStart" targetRef="fork" />

<inclusiveGateway id="fork" />
<sequenceFlow sourceRef="fork" targetRef="receivePayment" >
  <conditionExpression xsi:type="tFormalExpression">${paymentReceived == false}</conditionExpression>
</sequenceFlow>
<sequenceFlow sourceRef="fork" targetRef="shipOrder" >
  <conditionExpression xsi:type="tFormalExpression">${shipOrder == true}</conditionExpression>
</sequenceFlow>

<userTask id="receivePayment" name="Receive Payment" />
<sequenceFlow sourceRef="receivePayment" targetRef="join" />

<userTask id="shipOrder" name="Ship Order" />
<sequenceFlow sourceRef="shipOrder" targetRef="join" />

<inclusiveGateway id="join" />
<sequenceFlow sourceRef="join" targetRef="archiveOrder" />

<userTask id="archiveOrder" name="Archive Order" />
<sequenceFlow sourceRef="archiveOrder" targetRef="theEnd" />

<endEvent id="theEnd" />

 

4. TASKS

 

 4.1 User Task

需要用戶參與的任務

humanPerformer 方式，指定一個執行人

<userTask id='theTask' name='important task' >
    <humanPerformer>
      <resourceAssignmentExpression>
        <formalExpression>kermit</formalExpression>
      </resourceAssignmentExpression>
    </humanPerformer>
  </userTask>

potentialOwner 多個人或組

<userTask id='theTask' name='important task' >
    <potentialOwner>
      <resourceAssignmentExpression>
        <formalExpression>user(kermit), group(management)</formalExpression>
      </resourceAssignmentExpression>
    </potentialOwner>
  </userTask>

還有通過屬性來設置

• <userTask id="theTask" name="my task" activiti:assignee="kermit" />
• <userTask id="theTask" name="my task" activiti:candidateUsers="kermit, gonzo" />
• <userTask id="theTask" name="my task" activiti:candidateGroups="management, accountancy" />

4.2 Script Task

略

4.3 Java Service Task

4.4 Business Rule Task

業務邏輯任務，使用JBoss Drools 規則引擎來處理輸入輸出；

<process id="simpleBusinessRuleProcess">

  <startEvent id="theStart" />
  <sequenceFlow sourceRef="theStart" targetRef="businessRuleTask" />

  <businessRuleTask id="businessRuleTask" activiti:ruleVariablesInput="${order}"
      activiti:resultVariable="rulesOutput" />

  <sequenceFlow sourceRef="businessRuleTask" targetRef="theEnd" />

  <endEvent id="theEnd" />

</process>

4.5 Camel Task

camel.apache 規則引擎任務，一個例子

<process id="PingPongProcess">
  <startEvent id="start"/>
  <sequenceFlow id="flow1" sourceRef="start" targetRef="ping"/>
  <serviceTask id="ping" activiti:type="camel"/>
  <sequenceFlow id="flow2" sourceRef="ping" targetRef="saveOutput"/>
  <serviceTask id="saveOutput"  activiti:class="org.activiti.camel.examples.pingPong.SaveOutput" />
  <sequenceFlow id="flow3" sourceRef="saveOutput" targetRef="end"/>
  <endEvent id="end"/>
</process>

org.activiti.camel.examples.pingPong.SaveOutput類

@Override
public void configure() throws Exception {
  from("activiti:PingPongProcess:ping").transform().simple("${property.input} World");
}

測試代碼：

@Deployment
public void testPingPong() {
  Map<String, Object> variables = new HashMap<String, Object>();

  variables.put("input", "Hello");
  Map<String, String> outputMap = new HashMap<String, String>();
  variables.put("outputMap", outputMap);

  runtimeService.startProcessInstanceByKey("PingPongProcess", variables);
  assertEquals(1, outputMap.size());
  assertNotNull(outputMap.get("outputValue"));
  assertEquals("Hello World", outputMap.get("outputValue"));
}

 

 

 

5. Sub-Processes and Call Activities 子流程

 子流程是嵌入式的，不可重用，必須從None Start Event開始

而Call Activities本身調用的就是完整的流程

 

7. Process Initiation Authorization 初始化認證

 

<process id="potentialStarter">
  <extensionElements>
    <activiti:potentialStarter>
       <resourceAssignmentExpression>
         <formalExpression>group2, group(group3), user(user3)</formalExpression>
       </resourceAssignmentExpression>
    </activiti:potentialStarter>
  </extensionElements>

  <startEvent id="theStart"/>
  ...
或
<process id="potentialStarter" activiti:candidateStarterUsers="user1, user2"
                               activiti:candidateStarterGroups="group1">
      ...

 

8. Data objects 流程數據

 

<process id="dataObjectScope" name="Data Object Scope" isExecutable="true">
  <dataObject id="dObj123" name="StringTest123" itemSubjectRef="xsd:string">
    <extensionElements>
      <activiti:value>Testing123</activiti:value>
    </extensionElements>
  </dataObject>
  ...

 

9. Form properties 表單屬性

• StartFormData FormService.getStartFormData(String processDefinitionId)
• TaskFormdata FormService.getTaskFormData(String taskId)

<userTask id="task">
  <extensionElements>
    <activiti:formProperty id="room" />
    <activiti:formProperty id="duration" type="long"/>
    <activiti:formProperty id="speaker" variable="SpeakerName" writable="false" />
    <activiti:formProperty id="street" expression="#{address.street}" required="true" />
  </extensionElements>
</userTask>

表單屬性 room 對應--〉 流程變量 room 類型： String
表單屬性 duration 對應--〉 流程變量 duration 類型： java.lang.Long
表單屬性 speaker 對應--〉 流程變量 SpeakerName. 它是TaskFormData對象.
表單屬性 street 對應--〉 Java bean 屬性 street定義在流程變量 address

<startEvent id="start">
  <extensionElements>
    <activiti:formProperty id="speaker"
      name="Speaker"
      variable="SpeakerName"
      type="string" />

    <activiti:formProperty id="start"
      type="date"
      datePattern="dd-MMM-yyyy" />

    <activiti:formProperty id="direction" type="enum">
      <activiti:value id="left" name="Go Left" />
      <activiti:value id="right" name="Go Right" />
      <activiti:value id="up" name="Go Up" />
      <activiti:value id="down" name="Go Down" />
    </activiti:formProperty>

  </extensionElements>
</startEvent>

<startEvent>
  <extensionElements>
    <activiti:formProperty id="numberOfDays" name="Number of days" value="${numberOfDays}" type="long" required="true"/>
    <activiti:formProperty id="startDate" name="First day of holiday (dd-MM-yyy)" value="${startDate}" datePattern="dd-MM-yyyy hh:mm" type="date" required="true" />
    <activiti:formProperty id="vacationMotivation" name="Motivation" value="${vacationMotivation}" type="string" />
  </extensionElements>
</userTask>

 

表單：

10. External form rendering 外部表單集成

 提交表單屬性，第三方表單系統發送數據：

ProcessInstance FormService.submitStartFormData(String processDefinitionId, Map<String,String> properties)
 
FormService.submitTaskFormData(String taskId, Map<String,String> properties)

獲得屬性，Acticiti接收處理數據：

• StartFormData FormService.getStartFormData(String processDefinitionId) 
• TaskFormdata FormService.getTaskFormData(String taskId).