点击标题进入项目，CommandHandler代码
@Profile("command")
@Aggregate
public class Bike {
@AggregateIdentifier
private String bikeId;
private boolean isAvailable;
public Bike() {
}
@CommandHandler
public Bike(RegisterBikeCommand command) {
apply(new BikeRegisteredEvent(command.getBikeId(), command.getLocation()));
}
@CommandHandler
public void handle(RentBikeCommand command) {
if (!this.isAvailable) {
throw new IllegalStateException("Bike is already rented");
}
apply(new BikeRentedEvent(command.getBikeId(), command.getRenter()));
}
@CommandHandler
public void handle(ReturnBikeCommand command) {
if (this.isAvailable) {
throw new IllegalStateException("Bike was already returned");
}
apply(new BikeReturnedEvent(command.getBikeId(), command.getLocation()));
}
@EventSourcingHandler
protected void handle(BikeRegisteredEvent event) {
this.bikeId = event.getBikeId();
this.isAvailable = true;
}
@EventSourcingHandler
protected void handle(BikeReturnedEvent event) {
this.isAvailable = true;
}
@EventSourcingHandler
protected void handle(BikeRentedEvent event) {
this.isAvailable = false;
}
}
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用于EventSourcing的历史实体：
@Profile("history")
@Entity
public class BikeHistory {
@Id
@GeneratedValue
private Long id;
private String bikeId;
private String description;
private String timestamp;
public BikeHistory() {
}
public BikeHistory(String bikeId, Instant timestamp, String description) {
this.bikeId = bikeId;
this.timestamp = timestamp.toString();
this.description = description;
}
public String getBikeId() {
return bikeId;
}
public String getDescription() {
return description;
}
public String getTimestamp() {
return timestamp;
}
}
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领域历史事件重播到当前状态：
@Profile("history")
@Component
public class BikeHistoryProjection {
private final BikeHistoryRepository bikeHistoryRepository;
private final QueryUpdateEmitter updateEmitter;
public BikeHistoryProjection(BikeHistoryRepository bikeHistoryRepository, QueryUpdateEmitter updateEmitter) {
this.bikeHistoryRepository = bikeHistoryRepository;
this.updateEmitter = updateEmitter;
}
@EventHandler
public void handle(BikeRegisteredEvent event, @Timestamp Instant timestamp) {
bikeHistoryRepository.save(new BikeHistory(event.getBikeId(), timestamp, "Bike registered in " + event.getLocation()));
}
@EventHandler
public void handle(BikeRentedEvent event, @Timestamp Instant timestamp) {
BikeHistory newEntry = new BikeHistory(event.getBikeId(), timestamp, "Bike rented out to " + event.getRenter());
bikeHistoryRepository.save(newEntry);
updateEmitter.emit(m -> "locationHistory".equals(m.getQueryName())
&& newEntry.getBikeId().equals(m.getPayload()),
newEntry);
}
@EventHandler
public void handle(BikeReturnedEvent event, @Timestamp Instant timestamp) {
BikeHistory newEntry = new BikeHistory(event.getBikeId(), timestamp, "Bike returned in " + event.getLocation());
bikeHistoryRepository.save(newEntry);
updateEmitter.emit(m -> "locationHistory".equals(m.getQueryName())
&& newEntry.getBikeId().equals(m.getPayload()),
newEntry);
}
@QueryHandler(queryName = "locationHistory")
public List<BikeHistory> findMovements(String bikeId) {
return bikeHistoryRepository.findByBikeIdOrderById(bikeId);
}
}
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领域事件历史使用Spring JPA持久：
@Profile("history")
public interface BikeHistoryRepository extends JpaRepository<BikeHistory, Long> {
List<BikeHistory> findByBikeIdOrderById(String bikeId);
}
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