相关疑难解决方法(0)

有时我会看到大量的Scala代码,有几个嵌套的条件和匹配级别,使用显式返回退出函数会更清楚.

避免那些明确的退货声明有什么好处吗？

在验证几个连续条件时,我经常会遇到很多嵌套的.map和.getOrElse

例如:

def save() = CORSAction { request =>
  request.body.asJson.map { json =>
    json.asOpt[Feature].map { feature =>
      MaxEntitiyValidator.checkMaxEntitiesFeature(feature).map { rs =>
        feature.save.map { feature => 
          Ok(toJson(feature.update).toString)
        }.getOrElse {
          BadRequest(toJson(
            Error(status = BAD_REQUEST, message = "Error creating feature entity")
          ))
        }
      }.getOrElse {
        BadRequest(toJson(
          Error(status = BAD_REQUEST, message = "You have already reached the limit of feature.")
        )) 
      }
    }.getOrElse {
      BadRequest(toJson(
        Error(status = BAD_REQUEST, message = "Invalid feature entity")
      )) 
    }
  }.getOrElse {
    BadRequest(toJson(
      Error(status = BAD_REQUEST, message = "Expecting …