ext> builder = StateMachineBuilderFactory.create();
// 接单后，运输需求单生成运输规划单
builder.externalTransition()
.from(None)
.to(UN_ASSIGN_CARRIER)
.on(Create_Event)
.when(checkCondition())
.perform(doAction());
// 运输规划单生成调度单，调度单绑定服务商
builder.externalTransition()
.from(UN_ASSIGN_CARRIER)
.to(UN_ASSIGN_CAR)
.on(Assign_Carrier_Event)
.when(checkCondition())
.perform(doAction());
// 服务商分配车辆、司机
builder.externalTransition()
.from(UN_ASSIGN_CAR)
.to(ASSIGNED_CAR)
.on(Assign_Car_Event)
.when(checkCondition())
.perform(doAction());
// 货物揽收
builder.externalTransition()
.from(ASSIGNED_CAR)
.to(PICKUPED)
.on(Trans_Job_Status_Change_Event)
.when(checkCondition())
.perform(doAction());
// 揽收货物更新到运输中
builder.externalTransition()
.from(ASSIGNED_CAR)
.to(IN_TRANSIT)
.on(Trans_Job_Status_Change_Event)
.when(checkCondition())
.perform(doAction());
// 运输中更新到过海关
builder.externalTransition()
.from(IN_TRANSIT)
.to(PASS_CUSTOMS)
.on(Trans_Job_Status_Change_Event)
// 检查是否需要过海关
.when(isTransNeedPassCustoms())
.perform(doAction());
// 妥投
builder.externalTransition()
.from(PASS_CUSTOMS)
.to(ALL_DELIVERIED)
.on(All_Delivery_Event)
.when(checkCondition())
.perform(doAction());
// 车辆揽收、运输、过海关的运输状态，都可以直接更新到妥投
Stream.of(PICKUPED, IN_TRANSIT, PASS_CUSTOMS)
.forEach(status ->
builder.externalTransition()
.from(status)
.to(ALL_DELIVERIED)
.on(Trans_Job_Status_Change_Event)
.when(checkCondition())
.perform(doAction())
);
// 待分配、待派车、已派车可取消
Stream.of(UN_ASSIGN_CARRIER, UN_ASSIGN_CAR, ASSIGNED_CAR)
.forEach(status ->
builder.externalTransition()
.from(status)
.to(CANCELED)
.on(Order_Cancel_Event)
.when(checkCondition())
.perform(doAction())
);
// 妥投、和取消可结束归档
Stream.of(ALL_DELIVERIED, CANCELED)
.forEach(status ->
builder.externalTransition()
.from(status)
.to(FINISH)
.on(Order_Finish)
.when(checkCondition())
.perform(doAction())
);
stateMachine = builder.build("TransNeedStatusMachine");
从代码中，可以方便的扩展状态和对应的事件，状态机自动进行业务状态的流转。生成的状态流转图如下所示：
@startuml
None --> UN_ASSIGN_CARRIER : Create_Event
UN_ASSIGN_CARRIER --> UN_ASSIGN_CAR : Assign_Carrier_Event
UN_ASSIGN_CAR --> ASSIGNED_CAR : Assign_Car_Event
ASSIGNED_CAR --> CANCELED : Order_Cancel_Event
ASSIGNED_CAR --> PICKUPED : Trans_Job_Status_Change_Event
ASSIGNED_CAR --> IN_TRANSIT : Trans_Job_Status_Change_Event
IN_TRANSIT --> PASS_CUSTOMS : Trans_Job_Status_Change_Event
PASS_CUSTOMS --> ALL_DELIVERIED : Trans_Job_Status_Change_Event
PASS_CUSTOMS --> ALL_DELIVERIED : All_Delivery_Event
IN_TRANSIT --> ALL_DELIVERIED : Trans_Job_Status_Change_Event
ALL_DELIVERIED --> FINISH : Order_Finis
UN_ASSIGN_CAR --> CANCELED : Order_Cancel_Event
UN_ASSIGN_CARRIER --> CANCELED : Order_Cancel_Event
PICKUPED --> ALL_DELIVERIED : Trans_Job_Status_Change_Event
CANCELED --> FINISH : Order_Finis
@enduml
4.2.2 状态机事件处理
/**
* 一种是通过Event来进行事件分发，不同Event通过EventBus走不同的事件响应
* 另一种是在构造状态机时，直接配置不同的Action
* @return
*/
private Action<TransNeedStatusEnum, TransNeedEventEnum, Context> doAction() {
log.info("do action");
return (from, to, event, ctx) -> {
log.info(ctx.getUserName(