AggregateMember 继承：没有处理程序订阅命令

Question

我有以下聚合，其中包含一个聚合成员。

@Aggregate
public class CpaAggregate {

    @AggregateIdentifier
    private String externalId;

    @AggregateMember
    private Entity entity;

    public CpaAggregate() {
    }

    @CommandHandler
    public CpaAggregate(CreateCpaCommand cmd) {
        AggregateLifecycle.apply(new CpaCreatedEvent(...));
    }

    @EventSourcingHandler
    protected void on(CpaCreatedEvent evt) {
      ....
    }

}

public class Entity {

    @EntityId
    private String entityId;
    
    private Set<Identifier> identifiers = new HashSet<>();

    public Entity() {
    }

    @EventSourcingHandler
    public void on(IdentifiantUpdatedEvent evt) {
        ...
    }
    
}

public class Laboratory extends Entity {

    private OperatingSystem operatingSystem;

    public Laboratory() {
    }
    
    @CommandHandler
    public void handle(UpdateIdentifierLABCommand cmd) {
       AggregateLifecycle.apply(new IdentifiantUpdatedEvent(....));
    }
    
}

.

commandGateway.sendAndWait(new UpdateIdentifierLABCommand(...));

当我发送更新实验室类型实体标识符的命令时，出现此错误

org.axonframework.commandhandling.NoHandlerForCommandException: No handler was subscribed to command [UpdateIdentifierLABCommand]

Answer 1

Aymen，我会为您的 CpaAggregate 建模略有不同。

我不会使用通用的 Entity 聚合成员，而是使用更具体的实体，例如 Laboratory 实例。

一方面，随着模型结构变得更加清晰，这一点变得更加清晰 modeling-wise。其次，Axon Framework 将向上移动到父 class 以了解具体情况。因此，您仍然可以在 Entity class 中拥有公共信息，例如实体标识符、命令处理程序和事件源处理程序。

因此我会这样调整它：

@Aggregate
public class CpaAggregate {

    @AggregateIdentifier
    private String externalId;

    @AggregateMember
    private Laboratory laboratory;

    public CpaAggregate() {
    }

    @CommandHandler
    public CpaAggregate(CreateCpaCommand cmd) {
        AggregateLifecycle.apply(new CpaCreatedEvent(...));
    }

    @EventSourcingHandler
    protected void on(CpaCreatedEvent evt) {
      ....
    }

}

顺便说一句，这应该确保 Axon Framework 也能在聚合成员中发现命令处理程序。

AggregateMember 继承：没有处​​理程序订阅命令

AggregateMember inheritance: No handler was subscribed to command

axon

AggregateMember 继承：没有处理程序订阅命令