上一節(jié)我們介紹了如何構(gòu)建一個(gè)狀態(tài)機(jī)對(duì)象弄喘，接下來(lái)我們開(kāi)始介紹外部業(yè)務(wù)代碼如何調(diào)用狀態(tài)機(jī)
定義事件管理接口
/**
* Author: lehu
* Description: 狀態(tài)機(jī)事件管理類则拷，封裝外部業(yè)務(wù)代碼的調(diào)用
* Date: Create in 上午11:34 20/5/22
*/
public interface IStateMachineEventManager<E> {
/**
* 觸發(fā)發(fā)送狀態(tài)變更事件
* @param statusModelDO 狀態(tài)機(jī)模型對(duì)象
* @throws Exception
*/
<R> R sendStatusChangeEvent(StatusModelDO statusModelDO, E eventEnum);
}
- 該接口主要封裝了外部業(yè)務(wù)代碼對(duì)狀態(tài)機(jī)的調(diào)用贡蓖，只需要傳入當(dāng)前需要觸發(fā)的事件，以及對(duì)應(yīng)邏輯處理的參數(shù)對(duì)象即可煌茬。
定義抽象類
/**
* Author: lehu
* Description:
* Date: Create in 上午11:58 20/5/22
*/
@Slf4j
public abstract class AbstractStateMachineEventManager<S, E> implements IStateMachineEventManager<E> {
@Autowired
private StateMachineBuildFactory<S, E> stateMachineBuildFactory;
//用于狀態(tài)機(jī)上下文持久化
public abstract void stateMachinePersist(StateMachine<S, E> stateMachine, PersisterDO persisterDO) throws Exception;
//用于狀態(tài)機(jī)上下文初始化
public abstract StateMachine<S, E> stateMachineRestore(StateMachine<S, E> stateMachine, PersisterDO persisterDO) throws Exception;
@Override
@SuppressWarnings("unchecked")
public <R> R sendStatusChangeEvent(StatusModelDO statusModelDO, E eventEnum) {
//初始化當(dāng)前狀態(tài)機(jī)
StateMachine<S, E> stateMachine = initializeMachine(statusModelDO);
//執(zhí)行狀態(tài)機(jī)事件
Boolean result = statusChangeExecute(stateMachine, statusModelDO, eventEnum);
if (!result) {
throw new RuntimeException("狀態(tài)機(jī)狀態(tài)執(zhí)行失敗");
}
//執(zhí)行過(guò)程異常處理
RuntimeException exception = (RuntimeException)stateMachine.getExtendedState().getVariables().get(RuntimeException.class);
if (exception != null) {
//業(yè)務(wù)異常
if (exception instanceof BizException) {
throw exception;
//其他異常
} else {
log.error("狀態(tài)機(jī)內(nèi)部異常:{}",exception.getMessage(),exception);
if( eventEnum instanceof TakeChangeEventEnum ){
throw new BizException(BasicCode.UNDEFINED_ERROR, ((TakeChangeEventEnum)eventEnum).getDesc() +"處理異常");
}
throw new BizException(BasicCode.UNDEFINED_ERROR, "狀態(tài)機(jī)內(nèi)部異常斥铺，請(qǐng)檢查接口程序");
}
}
try {
//持久化狀態(tài)機(jī)
PersisterDO persisterDO = new PersisterDO();
persisterDO.setBizId(statusModelDO.getBizId());
stateMachinePersist(stateMachine, persisterDO);
} catch (Exception e) {
log.error("狀態(tài)機(jī)持久化失敗:{}",e.getMessage(),e);
throw new RuntimeException("狀態(tài)機(jī)持久化失敗");
}
return (R)stateMachine.getExtendedState().getVariables().get(StateMachineConstants.RETURN_PARAM);
}
/**
* 獲取狀態(tài)機(jī)對(duì)象
* @param statusModelDO 狀態(tài)模型對(duì)象
* @return 狀態(tài)機(jī)
*/
private StateMachine<S, E> initialize initializeMachine(StatusModelDO statusModelDO) {
log.info("StatusModelDO:" + JSON.toJSONString(statusModelDO));
//構(gòu)造狀態(tài)機(jī)模板
StateMachine<S, E> stateMachine;
try {
//構(gòu)造初始化狀態(tài)機(jī)
StateMachine<S, E> srcStateMachine = stateMachineBuildFactory.createStateMachine(getStateMachineType());
//構(gòu)造當(dāng)前執(zhí)行狀態(tài)
PersisterDO persisterDO = new PersisterDO();
persisterDO.setBizId(statusModelDO.getBizId());
persisterDO.setCurrentState(statusModelDO.getCurrentState());
//恢復(fù)當(dāng)前狀態(tài)機(jī)的上下文內(nèi)容
stateMachine = stateMachineRestore(srcStateMachine, persisterDO);
} catch (Exception e) {
throw new RuntimeException("初始化狀態(tài)機(jī)失敗");
}
if (stateMachine == null) {
throw new RuntimeException("沒(méi)有找到可用的狀態(tài)機(jī)");
}
log.info("stateMachine:" + JSON.toJSONString(stateMachine));
return stateMachine;
}
private boolean statusChangeExecute(StateMachine<S, E> stateMachine, StatusModelDO statusModelDO, E eventEnum) {
log.info("事件請(qǐng)求statusChangeExecute:" + eventEnum);
//構(gòu)建消息對(duì)象
Message<E> eventMsg = MessageBuilder.withPayload(eventEnum)
.setHeader(StateMachineConstants.STATE_MODEL_DTO, statusModelDO).build();
if (!acceptEvent(stateMachine, eventMsg)) {
throw new RuntimeException("找不到對(duì)應(yīng)狀態(tài)機(jī)事件觸發(fā)定義");
}
return stateMachine.sendEvent(eventMsg);
}
/**
* 事件執(zhí)行條件判斷
*/
private static <S, E> boolean acceptEvent(StateMachine<S, E> stateMachine, Message<E> eventMsg) {
//獲取當(dāng)前狀態(tài)
State<S, E> currentState = stateMachine.getState();
for (Transition<S, E> transition : stateMachine.getTransitions()) {
State<S, E> source = transition.getSource();
Trigger<S, E> trigger = transition.getTrigger();
if (currentState != null && trigger != null &&
StateMachineUtils.containsAtleastOne(source.getIds(), currentState.getIds()) &&
trigger.evaluate(new DefaultTriggerContext<>(eventMsg.getPayload()))) {
return true;
}
}
return false;
}
/**
* 獲取狀態(tài)機(jī)類型
* @return 狀態(tài)機(jī)類型
*/
public abstract String getStateMachineType();
}
- 該抽象類主要實(shí)現(xiàn)了，如何初始化一個(gè)狀態(tài)機(jī)對(duì)象坛善，并根據(jù)當(dāng)前的事件觸發(fā)狀態(tài)機(jī)對(duì)應(yīng)的節(jié)點(diǎn)動(dòng)作晾蜘，最后對(duì)執(zhí)行后的狀態(tài)機(jī)對(duì)象做持久化處理。
定義具體類型的事件管理實(shí)現(xiàn)類
/**
* Author: lehu
* Description:
* Date: Create in 下午4:16 20/5/22
*/
@Component
public class OrderStateMachineEventManager extends AbstractStateMachineEventManager<OrderStatusEnum, OrderChangeEventEnum> {
@Resource(name = "orderStateMachinePersister")
private StateMachinePersister<OrderStatusEnum, OrderChangeEventEnum, PersisterDO> stateMachinePersister;
@Override
public void stateMachinePersist(StateMachine<OrderStatusEnum, OrderChangeEventEnum> stateMachine,
PersisterDO persisterDO) throws Exception {
stateMachinePersister.persist(stateMachine, persisterDO);
}
@Override
public StateMachine<OrderStatusEnum, OrderChangeEventEnum> stateMachineRestore(
StateMachine<OrderStatusEnum, OrderChangeEventEnum> stateMachine,
PersisterDO persisterDO) throws Exception {
persisterDO.setMachineId(IStateMachineBuilder.ORDER_BUILDER_NAME);
return stateMachinePersister.restore(stateMachine, persisterDO);
}
@Override
public String getStateMachineType() {
return IStateMachineBuilder.ORDER_BUILDER_NAME;
}
}
- 本節(jié)介紹了外部調(diào)用狀態(tài)機(jī)的實(shí)現(xiàn)方式浑吟，下一節(jié)介紹改管理類中對(duì)于狀態(tài)機(jī)上下文持久化的實(shí)現(xiàn)。
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