Solon v3.1.2

solon-flow - 六大特色总结

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1、使用 yaml 格式

配置简洁，关系清晰

# c1.yml
id: "c1"
layout: 
  - { id: "n1", type: "start", link: "n2"}
  - { id: "n2", type: "execute", link: "n3"}
  - { id: "n3", type: "end"}

还支持简化模式（能自动推断的，都会自动处理），具体参考相关说明

# c1.yml
id: "c1"
layout: 
  - { type: "start"}
  - { task: ""}
  - { type: "end"}

2、表达式与脚本自由

# c2.yml
id: "c2"
layout: 
  - { type: "start"}
  - { when: "order.getAmount() >= 100", task: "order.setScore(0);"}
  - { when: "order.getAmount() > 100 && order.getAmount() <= 500", task: "order.setScore(100);"}
  - { when: "order.getAmount() > 500 && order.getAmount() <= 1000", task: "order.setScore(500);"}
  - { type: "end"}

3、元信息配置，为扩展提供了无限空间

# c3.yml
id: "c3"
layout: 
  - { id: "n1", type: "start", link: "n2"}
  - { id: "n2", type: "execute", link: "n3", meta: {cc: "demo@noear.org"}, task: "@MetaProcessCom"}
  - { id: "n3", type: "end"}

通过组件方式，实现元信息的抄送配置效果

@Component("MetaProcessCom")
public class MetaProcessCom implements TaskComponent {
    @Override
    public void run(FlowContext context, Node node) throws Throwable {
       String cc = node.getMeta("cc");
       if(Utils.isNotEmpty(cc)){
           //发送邮件...
       }
    }
}

也可通过驱动定制方式，实现抄送效果（显得重一些）

public class OaFlowDriver extends SimpleFlowDriver {
    @Override
    public void handleTask(FlowContext context, Task task) throws Throwable {
        if (Utils.isEmpty(task.getDescription())) {
           String cc = task.getNode().getMeta("cc");
           if(Utils.isNotEmpty(cc)){
               //发送邮件
           }
        } else {
            super.handleTask(context, task);
        }
    }
}

//FlowEngine flowEngine = FlowEngine.newInstance();
//flowEngine.register(new OaFlowDriver()); //替换掉默认驱动

4、事件广播与回调支持

广播（即只需要发送），回调（即发送后要求给答复）

id: f4
layout:
  - task: |
      //只发送
      context.<String,String>eventBus().send("demo.topic", "hello");  //支持泛型（类型按需指定，不指定时为 object）
  - task: |
      //发送并要求响应（就是要给答复）
      String rst = context.<String,String>eventBus().sendAndRequest("demo.topic.get", "hello");
      System.out.println(rst);

5、支持无状态、有状态两种应用

...

6、驱动定制（是像 JDBC 有 MySql, PostgreSQL，还可能有 Elasticsearch）

这是一个定制后的，支持基于状态驱动的流引擎效果。

StatefulFlowEngine flowEngine = new StatefulFlowEngine(StatefulSimpleFlowDriver.builder()
                .stateOperator(new MetaStateOperator("actor"))
                .stateRepository(new InMemoryStateRepository())
                .build());
                
var context = new StatefulFlowContext("i1").put("actor", "陈鑫");

//获取上下文用户的活动节点
var statefulNode = flowEngine.getActivityNode("f1", context);

assert "step2".equals(statefulNode.getNode().getId());
assert StateType.UNKNOWN == statefulNode.getState(); //没有权限启动任务（因为没有配置操作员）

//提交活动状态
flowEngine.postActivityState(context, "f1", statefulNode.getNode().getId(), StateType.COMPLETED);

流程配置样例：

id: f1
layout:
  - {id: step1, title: "发起审批", type: "start"}
  - {id: step2, title: "抄送", meta: {cc: "吕方"}, task: "@OaMetaProcessCom"}
  - {id: step3, title: "审批", meta: {actor: "陈鑫", cc: "吕方"}, task: "@OaMetaProcessCom"}
  - {id: step4, title: "审批", type: "parallel", link: [step4_1, step4_2]}
  - {id: step4_1, meta: {actor: "陈宇"}, link: step4_end}
  - {id: step4_2, meta: {actor: "吕方"}, link: step4_end}
  - {id: step4_end, type: "parallel"}
  - {id: step5, title: "抄送", meta: {cc: "吕方"}, task: "@OaMetaProcessCom"}
  - {id: step6, title: "结束", type: "end"}

对于驱动器的定制，我们还可以：定制（或选择）不同的脚本执行器、组件容器实现等。