@Service
@AllArgsConstructor
public class StockService extends BaseMapper<Product> {
    //京東服務(wù)
    private final JdService jdService;
    //淘寶服務(wù)
    private final TaobaoService productService;
    //有贊服務(wù)
    private final YouzanService youzanService;
    //拼多多服務(wù)
    private final pddService pddService;
    //更多服務(wù)
    ...
    //設(shè)置商品庫(kù)存
    @Override
    public void changeProductStock(ChangeProductStockInputDTO inputDTO) {
        if(inputDTO.getStock<0){
          throw new BusinessException("庫(kù)存不能小于0");
        }
        Product product = baseMapper.getById(inputDTO.getId());
        product.setStock(inputDTO.getStock());
        baseMapper.updateById(product);
        //通知京東
        jdService.notify();
        //通知淘寶
        productService.notify();
        //通知有贊
        youzanService.notify();
        //更多需要執(zhí)行的業(yè)務(wù)...
    }
}

@Data
public class Product {
    //id
    private String id;
    //庫(kù)存
    private BigDecimal stock;
    //...
}

@Data
public class Product {
    public void changeStock(BigDecimal stock){
      if(delStatus == 1){
        throw new BusinessException("商品信息不存在");
      }
      if(stock < 0){
        throw new BusinessException("庫(kù)存不能小于0");
      }
      this.stock = stock;
      EventBus.instance().register(new ChangedProductStockDomainEvent(this));
    }
    //id
    private String id;
    //庫(kù)存
    private BigDecimal stock;
    //刪除狀態(tài)
    private int delStatus;
    //...
}
//名字盡量起得生動(dòng)一些，單詞語法的過去式，現(xiàn)在進(jìn)行時(shí)都具有意義
@Getter
@AllArgsConstructor
public class ChangedProductStockDomainEvent {
   private Product product;
}

@Service
@AllArgsConstructor
public class StockService extends BaseMapper<Product> {
    //設(shè)置商品庫(kù)存
    @Override
    public void changeProductStock(ChangeProductStockInputDTO inputDTO) {
        Product product = baseMapper.getById(inputDTO.getId());
        product.setProductStock(inputDTO.getProductStock());
    }
}

public class EventBus {
    public static EventBus instance() {
        return new EventBus();
    }
    private static final ThreadLocal<List<DomainEvent>> domainEvents = new ThreadLocal<>();
    public void init() {
        if (domainEvents.get() == null) {
            domainEvents.set(new ArrayList<>());
        }
    }
    public EventBus register(DomainEvent domainEvent) {
        List<DomainEvent> domainEventList = domainEvents.get();
        if (domainEventList == null)
            throw new IllegalArgumentException("domainEventList not init");
        domainEventList.add(domainEvent);
        return this;
    }
    /**
     * 獲取領(lǐng)域事件
     *
     * @return
     */
    public List<DomainEvent> getDomainEvent() {
        return domainEvents.get();
    }
    /**
     * 請(qǐng)空領(lǐng)域事件集合
     */
    public void reset() {
        domainEvents.set(null);
    }
}

@Aspect
@Component
@Slf4j
public class DomainEventProcessor {
    /**
     * 這里我是我對(duì)RocketMq的封裝
     */
    @Autowired
    private EventPublisherExecutor processPublisherExecutor;
    /**
     * 當(dāng)前上下文內(nèi)訂閱者
     */
    @Autowired
    protected ApplicationContext applicationContext;
    private static ThreadLocal<AtomicInteger> counter = new ThreadLocal<>();
    @Pointcut("within(com.github.tom.*.application..*)")
    public void aopRule() {
    }
    /**
     * 為當(dāng)前線程初始化EventBus
     */
    @Before("aopRule()")
    public void initEventBus(JoinPoint joinPoint) {
        log.debug("初始化領(lǐng)域事件槽");
        log.debug("切入切點(diǎn)信息：" + joinPoint.getSignature().toString());
        EventBus.instance().init();
        if (counter.get() == null) {
            counter.set(new AtomicInteger(0));
        }
        counter.get().incrementAndGet();
    }
    /**
     * 發(fā)布領(lǐng)域事件
     */
    @AfterReturning("aopRule()")
    public void publish() {
        int count = counter.get().decrementAndGet();
        if (count == 0) {
            try {
                List<DomainEvent> domainEventList = EventBus.instance().getDomainEvent();
                if (domainEventList != null && domainEventList.size() > 0) {
                    //進(jìn)程內(nèi)事件
                    domainEventList.forEach(domainEvent -> applicationContext.publishEvent(domainEvent));
                    //進(jìn)程外事件
                    domainEventList.forEach(domainEvent -> processPublisherExecutor.publish(domainEvent));
                }
            } finally {
                EventBus.instance().reset();
                counter.set(null);
            }
        }
    }
    @AfterThrowing(throwing = "ex", pointcut = "aopRule()")
    public void exception(Throwable ex) {
        log.error(ex.getMessage(), ex);
        EventBus.instance().reset();
        //釋放計(jì)數(shù)器
        counter.set(null);
    }
}

@Slf4j
public abstract class AbstractEventHandler<T extends EventData> implements SmartApplicationListener {
    private Class<?> clazzType;
    public AbstractEventHandler(Class<? extends ApplicationEvent> clazzType) {
        this.clazzType = clazzType;
    }
    @Override
    public boolean supportsEventType(Class<? extends ApplicationEvent> clazzType) {
        return clazzType == this.clazzType;
    }
    @Override
    public boolean supportsSourceType(Class<?> clazz) {
        return true;
    }
    @Override
    public void onApplicationEvent(ApplicationEvent applicationEvent) {
        onApplicationEventHandler((T) applicationEvent);
    }
    protected abstract void onApplicationEventHandler(T eventData);
}
@Slf4j
public abstract class AbstractPersistenceEventHandler<T extends EventData> extends AbstractEventHandler<T> {
    public AbstractPersistenceEventHandler(Class<? extends ApplicationEvent> clazzType) {
        super(clazzType);
    }
    @Override
    public int getOrder() {
        return 0;
    }
}
@Component
public class ChangeProductStockPersistenceEventHandler
        extends AbstractPersistenceEventHandler<ChangedProductStockDomainEvent> {
    @Autowired
    private ProductRepository productRepository;
    public CreatedPortalArticlePersistenceEventHandler() {
        super(CreatedPortalArticleDomainEvent.class);
    }
    @Override
    protected void onApplicationEventHandler(ChangedProductStockDomainEvent eventData) {
        if (portalArticleRepository.updateById(eventData.getProduct()) <= 0) {
            throw new BusinessException("數(shù)據(jù)操作錯(cuò)誤");
        }
    }
}

@Component
public class JdStockEventHandler {
    @Autowired
    private JdAppService jdAppService;
    /**
     * 庫(kù)存持久化事件
     *
     * @param eventData
     */
    @StreamListener(value = "product-channel")
    public void receive(@Payload ChangedProductStockDomainEvent eventData) {
        jdAppService.changingInventory(eventData);
    }
}

@Component
public class ProductStockTest {
    @Before
    public void setUp() {
      EventBus.instance().init();
    }
    @Test
    public void testChangeStockError() {
        Product product = new Product();
        product.setStock(BigDecimal.valueOf("-1"));
        product.changeStock();
    }
   @Test
    public void testChangeStockSuccess() {
        Product product = new Product();
        product.setStock(BigDecimal.valueOf("2"));
        product.changeStock();
        assertThat(product.getStock()).isEqualTo("2");
    }
}