Scala 抽象方法参数问题，T 列表

发布于 2024-08-18 11:03:47 字数 622 浏览 5 评论 0原文

我有一个辅助方法：

def controlStructure[T <: SomeObject](exceptions: Class[_]*)(body: => T) = { 
    try { 
        val tempObject = body 
        tempObject.callSomeMethod 
        Some(tempObject) 
    } catch { 
        case e if (exceptions.contains(e.getClass)) => None 
    } 
}

调用方式：

controlStructure[MySomeObject](classOf[Exception]) { getMySomeObjectSomehow }

其要点是在传入的实体上调用“callSomeMethod”（例如从 ORM 加载），它也顺便将事情包装在异常处理中。

我现在想添加一个新方法，它执行相同的操作，但对于 T 的集合 (java.util.List)。

我不确定语法以及在方法签名中使用 T 集合的结构，并且抽象类型参数定义。

感谢您的帮助。

原文

I have a helper method:

def controlStructure[T <: SomeObject](exceptions: Class[_]*)(body: => T) = { 
    try { 
        val tempObject = body 
        tempObject.callSomeMethod 
        Some(tempObject) 
    } catch { 
        case e if (exceptions.contains(e.getClass)) => None 
    } 
}

called with:

controlStructure[MySomeObject](classOf[Exception]) { getMySomeObjectSomehow }

the main point of which is to call the 'callSomeMethod' on the entity passed in (for example loaded from ORM), it incidentally wraps things up in exception handling too.

I would now like to add a new method which does the same thing but for a collection (java.util.List) of T.

I am unsure of the syntax, and structures to work with a collection of T in the method signature, and abstract type param definitions.

Thanks for your help.

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云巢 2024-08-25 11:03:47

对于 scala 列表，你想要这样的东西（我认为）：

  def controlStructure[T <: SomeObject](exceptions: Class[_]*)(body: => List[T]) = {
    try {
      val tempObject = body
      tempObject.foreach { _.callSomeMethod() }
      Some(tempObject)
    }
    catch {
      case e if (exceptions.contains(e.getClass)) => None
    } 
  }

我没有在 scala 中使用过 Java 列表，所以我猜你可以使用 java.util.List 来做到这一点，如下所示：

  def controlStructure[T <: SomeObject](exceptions: Class[_]*)(body: => java.util.List[T]) = {
    import scala.collection.JavaConversions._
    try {
      val tempObject = body
      tempObject foreach { _.callSomeMethod() }
      Some(tempObject)
    }
    catch {
      case e if (exceptions.contains(e.getClass)) => None
    } 
  }

With a scala list, you are wanting something like this (I think):

  def controlStructure[T <: SomeObject](exceptions: Class[_]*)(body: => List[T]) = {
    try {
      val tempObject = body
      tempObject.foreach { _.callSomeMethod() }
      Some(tempObject)
    }
    catch {
      case e if (exceptions.contains(e.getClass)) => None
    } 
  }

I haven't worked with Java lists in scala, so I'm guessing you could do it with java.util.List like this:

  def controlStructure[T <: SomeObject](exceptions: Class[_]*)(body: => java.util.List[T]) = {
    import scala.collection.JavaConversions._
    try {
      val tempObject = body
      tempObject foreach { _.callSomeMethod() }
      Some(tempObject)
    }
    catch {
      case e if (exceptions.contains(e.getClass)) => None
    } 
  }

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