Spring-Boot需要构造函数中的泛型类型

Question

I've encountered a problem in my code and I'm looking for a workaround. This is the class:

import org.axonframework.eventhandling.EventBus;
import org.axonframework.eventsourcing.EventSourcedAggregateRoot;
import org.axonframework.eventsourcing.EventSourcingRepository;
import org.axonframework.eventstore.EventStore;
import org.axonframework.repository.LockManager;
import org.axonframework.repository.PessimisticLockManager;
import org.axonframework.repository.Repository;
import org.springframework.stereotype.Component;

@Component
public class BaseCommandHandler<E extends EventSourcedAggregateRoot> {

  protected Repository<E> repository;
  protected LockManager lockManager;

  /**
   * @param eventBus eventBus.
   * @param eventStore eventStore.
   */
  public BaseCommandHandler(EventBus eventBus, EventStore eventStore) {
    this.lockManager = new PessimisticLockManager();
    EventSourcingRepository<E> newRepository =
        new EventSourcingRepository<>(E.class, eventStore, lockManager);
    newRepository.setEventBus(eventBus);
  }
}

The first problem I faced was that I cannot use E.class . Then I changed the constructor to the following:

  public BaseCommandHandler(EventBus eventBus, EventStore eventStore, Class<E> type) {
    this.lockManager = new PessimisticLockManager();
    EventSourcingRepository<E> newRepository =
        new EventSourcingRepository<>(type, eventStore, lockManager);
    newRepository.setEventBus(eventBus);
  }
}

But when I ran the app it failed to start because of Parameter 2 of constructor in com.domain.handlers.BaseCommandHandler required a bean of type 'java.lang.Class' that could not be found.

How can I solve this issue?

Answer 1

You can use GenericTypeResolver class:

Class<E> type = (Class<E>) GenericTypeResolver.resolveTypeArgument(getClass(), BaseCommandHandler.class);
EventSourcingRepository<E> newRepository = new EventSourcingRepository<>(type, eventStore, lockManager);