Question

我在nscala_time包中找到了这个有趣的行为（joda-time的scala版本）

import com.github.nscala_time.time.Imports._
import com.github.nscala_time.time.DurationBuilder

object tests {
  val x = 3 seconds
  //> x : is of type com.github.nscala_time.time.DurationBuilder

  val xx: DurationBuilder = 3 seconds
  //> fails to compile: 
  // class DurationBuilder in package time cannot be accessed in package com.github.nscala_time.time
}

我想要实现的是从nscala_time持续时间到scala.concurrent.Duration的隐式转换我需要这个，因为我在一个应用程序中使用RxScala和nscala_time。

// e.g. the following should be implicitly converted
// to nscala_time Duration first
// than to scala.lang.concurrent.Duration
3 seconds

nscala_time提供丰富的时间和时间。我的应用程序的日期api，而我在同一类中使用RxScala进行GUI响应。您可以下载一个简单的项目来玩：https://dl.dropboxusercontent.com/u/9958045/implicit_vs_private.zip

Answer 1

也许你可以使用隐式转换？（btw Duration在nscala中基本上是org.joda.time.Duration）：

scala> import com.github.nscala_time.time.Imports._
import com.github.nscala_time.time.Imports._

scala> implicit class DurationHelper(d:org.joda.time.Duration) {
     | def toScalaDuration = scala.concurrent.duration.Duration.apply(d.getMillis,scala.concurrent.duration.MILLISECONDS)
     | }
defined class DurationHelper

scala> val d = RichInt(3).seconds.toDuration
// toDuration method is defined for com.github.nscala_time.time.DurationBuilder
d: org.joda.time.Duration = PT3S

scala> def exfun(d:scala.concurrent.duration.Duration) = d.toString
exfun: (d: scala.concurrent.duration.Duration)String

scala> exfun(d)
res41: String = 3000 milliseconds

（这里不使用import scala.concurrent.duration._来避免与joda / nlscala的名字冲突）

Answer 2

来自scala-user群组：这是一个已知问题https://issues.scala-lang.org/browse/SI-1800

在Scala中，我可以通过隐式转换引用私有类型

2 个答案: