java - 在任何一种情况下都可以选择执行操作

Question

我有一个方法

   public Single<SignatureOrder> confirmPayment(PaymentEntity entity, Identity identity, ConfirmationRequest confirmationRequest) {
        return chooseClient(entity)
                .confirmPayment(identity, entity,confirmationRequest);
    }

我需要做一点修改，如果 confirmationRequest 是 null 然后调用 confirmPayment(identity, entity);

我怎么能说类似的话Optional.ofNullable(confirmationRequest) 然后 chooseClient(entity) 然后 ifPresent 调用 confirmPayment(identity, entity,confirmationRequest); ifNotPresent 调用 confirmPayment(identity, entity);

confirmPayment 的签名

 public Single<SignatureOrder> confirmPayment(Identity identity, PaymentEntity entity)
 public Single<SignatureOrder> confirmPayment(Identity identity, PaymentEntity entity, ConfirmationRequest confirmationRequest)

Answer 1

public Single<SignatureOrder> confirmPayment(PaymentEntity entity, Identity identity, ConfirmationRequest confirmationRequest) {
    return Optional.ofNullable(confirmationRequest)
      .map(cr -> chooseClient(entity).confirmPayment(identity, entity, cr)
      .orElseGet(() -> chooseClient(entity).confirmPayment(identity, entity);
}   

映射到 null 返回空，通过使用 orElseGet 如果它映射到空它会调用这个 lambda