camunda_07_gateways

目标

了解BPMN中常用网关的作用和特点

汇聚网关的注意事项(重要)

网关的incoming分支不推荐带条件, 因为条件的evaluation都是在前置节点完成时计算, 并不会在汇聚时做二次计算, 所以对汇聚条件的解读都是错误的.
我们总可以通过一个fork网关(带条件)+join网关(不带条件)的组合, 来实现带条件的汇聚效果.

增加default ongoing分支的说明

如果一个节点(Task或Gateway)增加了一个条件分支, 记得一定要增加一个default分支, 否则流程在执行时, 如果该条件不满足, 流程就会报流程无法执行的错误.
Gateway 设置default ongoing分支的方法: Camunda modeler 无法通过UI设置default分支, 只能通过改写xml设置, 方法是: 为gateway tag 增加default attribute, 缺省分支线上有一个back slash符号(/).

    <bpmn2:exclusiveGateway id="Gateway_xor" default="Flow_default">
      <bpmn2:outgoing>Flow_amount100</bpmn2:outgoing>
      <bpmn2:outgoing>Flow_default</bpmn2:outgoing>
    </bpmn2:exclusiveGateway>

default分支示例
3. 普通节点(如task)设置缺省分支的方法很简单, 只要path上不添加条件即为default分支. 需要说明的是, 该分支总是被执行.

BPMN 网关的作用和图标

网关不是流程真正处理节点, 是作为流程的一个控制节点存在, 用于流程的合并join和分支fork, 一个网关节点可以同时用于fork也可以同时用于join. Camunda 引擎并不会为网关生成对应的task记录.

排他网关 Exclusive gateway 页叫做 XOR gateway

作为fork的含义

只有第一个满足条件的分支被执行, 其他条件的分支不会被执行.
如果带条件的分支都不满足, 则执行缺省分支.
如果无后续分支可被执行, 流程会报错.
可以理解为只有一个分支获取execution token.

作为join的含义

只要有一个前置分支到达后, 即完成合并, 流程继续往下执行.

包容网关 inclusive gateway, 也叫做 OR gateway

作为fork的含义

所有满足条件的分支都会被执行, 每个分支都会生成execution.
如果带条件的分支都不满足, 则执行缺省分支.
如果无后续分支可被执行, 流程会报错.

作为join的含义

要求"所有"分支都必须达网关, 流程才会向后执行.

并行网关 Parallel gateway, 也叫做 AND gateway

作为fork的含义

各个后续分支会被无条件执行.

作为join的含义

要求"所有"分支都必须达网关, 流程才会向后执行.

复杂网关 Complex gateway

使用场景

使用代码实现的join和fork获取token的逻辑, 举例: 如果共有5个分支合并, 如果有3个分支令牌达到, 即想流程往后执行, 就只能使用代码实现该网关逻辑.

事件网关 Event gateway

使用场景

事件网关只能用于fork, 不能用于合并.
事件网关至少有两个outgoing分支, 只能有一个 incoming 分支.
事件网关只能后接 中间catch类事件 或 消息接收task
事件网关的多个分支, 一直处于等待状态, 直到其中一个分支的事件到达, 流程才会向后执行.

测试程序

java

package javatest;

import java.util.HashMap;
import java.util.Map;
import java.util.logging.Logger;

import org.camunda.bpm.client.ExternalTaskClient;

public class ExternalTaskTest {
	private final static Logger logger = Logger.getLogger(ExternalTaskTest.class.getName());

	private static void listenIncomingTask(ExternalTaskClient client, String taskName, Long amount) {
		client.subscribe(taskName).lockDuration(1000).handler((externalTask, externalTaskService) -> {
			// 业务逻辑
			Map<String, Object> variableMap = new HashMap<>();
			// 完成 Task
			externalTaskService.complete(externalTask, variableMap);

			// externalTaskService.fail
			logger.info(taskName + " task done");
		}).open();
	}

	private static void listenOutgoingTask(ExternalTaskClient client, String taskName) {
		client.subscribe(taskName).lockDuration(1000).handler((externalTask, externalTaskService) -> {
			// 获取流程信息
			Long amount = (Long) externalTask.getVariable("amount");
			logger.info("amount:" + amount);

			// 完成 Task
			externalTaskService.complete(externalTask);
			logger.info(taskName + " task done");
		}).open();
	}

	public static void main(String[] args) {
		logger.info("ExternalTaskClient setup");
		ExternalTaskClient client = ExternalTaskClient.create().baseUrl("http://localhost:8080/engine-rest")
				.asyncResponseTimeout(10000).build();

		listenOutgoingTask(client, "loan.A1");
		listenOutgoingTask(client, "loan.A2");
		listenOutgoingTask(client, "loan.A0");
		logger.info("Listening topics...");
	}
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.lzw</groupId>
  <artifactId>javatest</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
<dependencies>
  <dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.4.3</version>
</dependency>
 
<dependency>
    <groupId>com.hrakaroo</groupId>
    <artifactId>glob</artifactId>
    <version>0.9.0</version>
</dependency>
        <dependency>
            <groupId>org.camunda.bpm</groupId>
            <artifactId>camunda-external-task-client</artifactId>
            <version>7.17.0</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.6.1</version>
        </dependency>
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.1</version>
        </dependency>
</dependencies>
</project>

fork流程图

流程图

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:camunda="http://camunda.org/schema/1.0/bpmn" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_1xvrd7w" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="5.3.0" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.17.0">
  <bpmn:process id="process_xor_fork" name="网关测试1" isExecutable="true">
    <bpmn:startEvent id="Event_0vq0omt">
      <bpmn:outgoing>Flow_1456nu1</bpmn:outgoing>
    </bpmn:startEvent>
    <bpmn:exclusiveGateway id="Gateway_1uuz4q8" default="Flow_a0">
      <bpmn:incoming>Flow_1456nu1</bpmn:incoming>
      <bpmn:outgoing>Flow_a1</bpmn:outgoing>
      <bpmn:outgoing>Flow_a2</bpmn:outgoing>
      <bpmn:outgoing>Flow_a0</bpmn:outgoing>
    </bpmn:exclusiveGateway>
    <bpmn:sequenceFlow id="Flow_1456nu1" sourceRef="Event_0vq0omt" targetRef="Gateway_1uuz4q8" />
    <bpmn:sequenceFlow id="Flow_a1" name="${amount==1}" sourceRef="Gateway_1uuz4q8" targetRef="Activity_07wbjrr">
      <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression">${amount==1}</bpmn:conditionExpression>
    </bpmn:sequenceFlow>
    <bpmn:serviceTask id="Activity_07wbjrr" name="A1" camunda:type="external" camunda:topic="loan.A1">
      <bpmn:incoming>Flow_a1</bpmn:incoming>
      <bpmn:outgoing>Flow_0zhprh8</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:serviceTask id="Activity_0m749bw" name="A2" camunda:type="external" camunda:topic="loan.A2">
      <bpmn:incoming>Flow_a2</bpmn:incoming>
      <bpmn:outgoing>Flow_1ltvk8y</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:serviceTask id="Activity_0094ryg" name="A0" camunda:type="external" camunda:topic="loan.A0">
      <bpmn:incoming>Flow_a0</bpmn:incoming>
      <bpmn:outgoing>Flow_13xn64x</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:sequenceFlow id="Flow_a2" name="${amount==2}" sourceRef="Gateway_1uuz4q8" targetRef="Activity_0m749bw">
      <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression">${amount==2}</bpmn:conditionExpression>
    </bpmn:sequenceFlow>
    <bpmn:sequenceFlow id="Flow_a0" sourceRef="Gateway_1uuz4q8" targetRef="Activity_0094ryg" />
    <bpmn:endEvent id="Event_1l6225c">
      <bpmn:incoming>Flow_0zhprh8</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_0zhprh8" sourceRef="Activity_07wbjrr" targetRef="Event_1l6225c" />
    <bpmn:endEvent id="Event_0idkqv7">
      <bpmn:incoming>Flow_1ltvk8y</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_1ltvk8y" sourceRef="Activity_0m749bw" targetRef="Event_0idkqv7" />
    <bpmn:endEvent id="Event_1rno5kl">
      <bpmn:incoming>Flow_13xn64x</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_13xn64x" sourceRef="Activity_0094ryg" targetRef="Event_1rno5kl" />
  </bpmn:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="process_xor_fork">
      <bpmndi:BPMNShape id="Event_0vq0omt_di" bpmnElement="Event_0vq0omt">
        <dc:Bounds x="142" y="182" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Gateway_1uuz4q8_di" bpmnElement="Gateway_1uuz4q8" isMarkerVisible="true">
        <dc:Bounds x="245" y="175" width="50" height="50" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_0ydt8z4_di" bpmnElement="Activity_07wbjrr">
        <dc:Bounds x="440" y="70" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="BPMNShape_1vmcikm" bpmnElement="Activity_0m749bw">
        <dc:Bounds x="440" y="160" width="100" height="80" />
        <bpmndi:BPMNLabel />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="BPMNShape_0gnw5e0" bpmnElement="Activity_0094ryg">
        <dc:Bounds x="440" y="250" width="100" height="80" />
        <bpmndi:BPMNLabel />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1l6225c_di" bpmnElement="Event_1l6225c">
        <dc:Bounds x="662" y="92" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_0idkqv7_di" bpmnElement="Event_0idkqv7">
        <dc:Bounds x="662" y="182" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1rno5kl_di" bpmnElement="Event_1rno5kl">
        <dc:Bounds x="662" y="272" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="Flow_1456nu1_di" bpmnElement="Flow_1456nu1">
        <di:waypoint x="178" y="200" />
        <di:waypoint x="245" y="200" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1f5owlm_di" bpmnElement="Flow_a1">
        <di:waypoint x="270" y="175" />
        <di:waypoint x="270" y="110" />
        <di:waypoint x="440" y="110" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="250" y="140" width="70" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0cppjxi_di" bpmnElement="Flow_a2">
        <di:waypoint x="295" y="200" />
        <di:waypoint x="440" y="200" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="333" y="182" width="70" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0kjoevt_di" bpmnElement="Flow_a0">
        <di:waypoint x="270" y="225" />
        <di:waypoint x="270" y="310" />
        <di:waypoint x="440" y="310" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0zhprh8_di" bpmnElement="Flow_0zhprh8">
        <di:waypoint x="540" y="110" />
        <di:waypoint x="662" y="110" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1ltvk8y_di" bpmnElement="Flow_1ltvk8y">
        <di:waypoint x="540" y="200" />
        <di:waypoint x="662" y="200" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_13xn64x_di" bpmnElement="Flow_13xn64x">
        <di:waypoint x="540" y="290" />
        <di:waypoint x="662" y="290" />
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</bpmn:definitions>

post 请求

POST http://localhost:8080/engine-rest/process-definition/key/process_xor_fork/start HTTP/1.1
Content-Type: application/json

{
    "variables": {
        "amount": {
            "value":555,
            "type":"long"
        },
        "item": {
            "value": "item-xyz"
        }
    }
}

测试输出

程序输出

join 网关示例

仅附上流程, 测试java程序和运行结果略.
流程图

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:camunda="http://camunda.org/schema/1.0/bpmn" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_1xvrd7w" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="5.3.0" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.17.0">
  <bpmn:process id="process_xor_join" name="网关测试1" isExecutable="true">
    <bpmn:startEvent id="Event_1q3q8yh">
      <bpmn:outgoing>Flow_09irp9w</bpmn:outgoing>
    </bpmn:startEvent>
    <bpmn:startEvent id="Event_00b5w04">
      <bpmn:outgoing>Flow_1s7e1rv</bpmn:outgoing>
      <bpmn:conditionalEventDefinition id="ConditionalEventDefinition_0ai7vtt">
        <bpmn:condition xsi:type="bpmn:tFormalExpression">${amount==1}</bpmn:condition>
      </bpmn:conditionalEventDefinition>
    </bpmn:startEvent>
    <bpmn:serviceTask id="Activity_193j4cl" name="A1" camunda:type="external" camunda:topic="loan.A1">
      <bpmn:incoming>Flow_09irp9w</bpmn:incoming>
      <bpmn:outgoing>Flow_1lvacs3</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:serviceTask id="Activity_0fuwa2j" name="A2" camunda:type="external" camunda:topic="loan.A2">
      <bpmn:incoming>Flow_1s7e1rv</bpmn:incoming>
      <bpmn:outgoing>Flow_0t7aaxk</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:exclusiveGateway id="Gateway_1e0191l">
      <bpmn:incoming>Flow_1lvacs3</bpmn:incoming>
      <bpmn:incoming>Flow_0t7aaxk</bpmn:incoming>
      <bpmn:outgoing>Flow_1f8yubd</bpmn:outgoing>
    </bpmn:exclusiveGateway>
    <bpmn:sequenceFlow id="Flow_1lvacs3" sourceRef="Activity_193j4cl" targetRef="Gateway_1e0191l" />
    <bpmn:sequenceFlow id="Flow_0t7aaxk" sourceRef="Activity_0fuwa2j" targetRef="Gateway_1e0191l" />
    <bpmn:sequenceFlow id="Flow_09irp9w" sourceRef="Event_1q3q8yh" targetRef="Activity_193j4cl" />
    <bpmn:sequenceFlow id="Flow_1s7e1rv" name="${amount==1}" sourceRef="Event_00b5w04" targetRef="Activity_0fuwa2j" />
    <bpmn:serviceTask id="Activity_11vtbo0" name="A0" camunda:type="external" camunda:topic="loan.A0">
      <bpmn:incoming>Flow_1f8yubd</bpmn:incoming>
      <bpmn:outgoing>Flow_1hq8fo8</bpmn:outgoing>
    </bpmn:serviceTask>
    <bpmn:sequenceFlow id="Flow_1f8yubd" sourceRef="Gateway_1e0191l" targetRef="Activity_11vtbo0" />
    <bpmn:endEvent id="Event_1p6n34p">
      <bpmn:incoming>Flow_1hq8fo8</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_1hq8fo8" sourceRef="Activity_11vtbo0" targetRef="Event_1p6n34p" />
  </bpmn:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="process_xor_join">
      <bpmndi:BPMNShape id="Event_1q3q8yh_di" bpmnElement="Event_1q3q8yh">
        <dc:Bounds x="182" y="102" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="BPMNShape_1f8et6x" bpmnElement="Activity_193j4cl">
        <dc:Bounds x="320" y="80" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="BPMNShape_1ufbsl3" bpmnElement="Gateway_1e0191l" isMarkerVisible="true">
        <dc:Bounds x="475" y="135" width="50" height="50" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1kp5erq_di" bpmnElement="Event_00b5w04">
        <dc:Bounds x="182" y="212" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="BPMNShape_087lirz" bpmnElement="Activity_0fuwa2j">
        <dc:Bounds x="320" y="190" width="100" height="80" />
        <bpmndi:BPMNLabel />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="BPMNShape_0hn9274" bpmnElement="Activity_11vtbo0">
        <dc:Bounds x="590" y="120" width="100" height="80" />
        <bpmndi:BPMNLabel />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1p6n34p_di" bpmnElement="Event_1p6n34p">
        <dc:Bounds x="762" y="142" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="Flow_09irp9w_di" bpmnElement="Flow_09irp9w">
        <di:waypoint x="218" y="120" />
        <di:waypoint x="320" y="120" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1lvacs3_di" bpmnElement="Flow_1lvacs3">
        <di:waypoint x="420" y="120" />
        <di:waypoint x="448" y="120" />
        <di:waypoint x="448" y="160" />
        <di:waypoint x="475" y="160" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0t7aaxk_di" bpmnElement="Flow_0t7aaxk">
        <di:waypoint x="420" y="230" />
        <di:waypoint x="500" y="230" />
        <di:waypoint x="500" y="185" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1f8yubd_di" bpmnElement="Flow_1f8yubd">
        <di:waypoint x="525" y="160" />
        <di:waypoint x="590" y="160" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1s7e1rv_di" bpmnElement="Flow_1s7e1rv">
        <di:waypoint x="218" y="230" />
        <di:waypoint x="320" y="230" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="234" y="212" width="70" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1hq8fo8_di" bpmnElement="Flow_1hq8fo8">
        <di:waypoint x="690" y="160" />
        <di:waypoint x="762" y="160" />
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</bpmn:definitions>

参考

camunda-bpmn-网关（Gateways）

posted @ 2022-09-25 19:09 harrychinese 阅读(423) 评论(0) 编辑收藏举报

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harrychinese

camunda_07_gateways

目标

汇聚网关的注意事项(重要)

增加default ongoing分支的说明

BPMN 网关的作用和图标

排他网关 Exclusive gateway 页叫做 XOR gateway

包容网关 inclusive gateway, 也叫做 OR gateway

并行网关 Parallel gateway, 也叫做 AND gateway

复杂网关 Complex gateway

使用场景

事件网关 Event gateway

使用场景

测试程序

java

pom.xml

fork流程图

post 请求

测试输出

join 网关示例

参考

公告