我有一个简单的订单处理应用程序,并尝试应用弹簧状态机来处理订单的状态。我想知道如何在休息服务的多个请求期间处理相同订单的订单状态。
订单状态:
enum OrderEvents {
FULFILL,
PAY,
CANCEL
}
订单活动:
enum OrderStates {
SUBMITTED,
PAID,
FULFILLED,
CANCELLED
}
状态机配置:
@Log
@Configuration
@EnableStateMachineFactory
class SimpleEnumStatemachineConfiguration extends StateMachineConfigurerAdapter<OrderStates, OrderEvents> {
@Override
public void configure(StateMachineTransitionConfigurer<OrderStates, OrderEvents> transitions) throws Exception {
transitions
.withExternal().source(OrderStates.SUBMITTED).target(OrderStates.PAID).event(OrderEvents.PAY)
.and()
.withExternal().source(OrderStates.PAID).target(OrderStates.FULFILLED).event(OrderEvents.FULFILL)
.and()
.withExternal().source(OrderStates.SUBMITTED).target(OrderStates.CANCELLED).event(OrderEvents.CANCEL)
.and()
.withExternal().source(OrderStates.PAID).target(OrderStates.CANCELLED).event(OrderEvents.CANCEL);
}
@Override
public void configure(StateMachineStateConfigurer<OrderStates, OrderEvents> states) throws Exception {
states
.withStates()
.initial(OrderStates.SUBMITTED)
.state(OrderStates.PAID)
.end(OrderStates.FULFILLED)
.end(OrderStates.CANCELLED);
}
@Override
public void configure(StateMachineConfigurationConfigurer<OrderStates, OrderEvents> config) throws Exception {
config.withConfiguration()
.autoStartup(true)
}
}
在我的订单服务中,我打电话
StateMachine<OrderStates, OrderEvents> sm = this.factory.getStateMachine(orderIdKey);
但似乎每次都是为同一orderIdKey创建的新状态机。那么,如何在下次状态下提交订单时访问创建的状态机?
你基本上有两个选择:
a)使用orderId
坚持使用state machine persister的状态机,如here所述。
b)为给定的orderId
(每个HTTP请求)创建一个新的状态机,并根据给定order entity
的orderId
状态重新水化SM状态。 SM对象被认为是轻量级的,因此这也是一种可行的方法。以下是代码示例:
StateMachine<Status, Event> build(long orderId) {
orderService.getOrder(orderId) //returns Optional
.map(order -> {
StateMachine<Status, Event> sm = stateMachineFactory.getStateMachine(Long.toString(orderId));
sm.stop();
rehydrateState(sm, sm.getExtendedState, order.getStatus());
sm.start();
return sm;
})
.orElseGet(() -> createNewStateMachine(orderId);
}
void rehydrateState(StateMachine<Status, Event> newStateMachine, ExtendedState extendedState, Status orderStatus) {
newStateMachine.getStateMachineAccessor().doWithAllRegions(sma ->
sma.resetStateMachine(new DefaultStateMachineContext<>(orderStatus, null, null, extendedState));
});
}