配置生成

Question

让我们说，我在斯卡拉实现（像一个从this post sugested）的通用组件：

import scala.collection.mutable.Map 

sealed trait Language { 
    val messages: Map[String, String] 
} 
class English extends Language { 
    val messages: Map[String, String] = 
    Map("M01" -> "Ready for cooking - press START", 
     "M02" -> "Close the door to start cooking") 
} 
class French extends Language { 
    val messages: Map[String, String] = 
    Map("M01" -> "Pret pour la cuisson - presse START", 
     "M02" -> "Fermez la porte pour commencer la cuisson") 
} 
class Lang[A <: Language] { 

    private var language: Language = new English 

    def chosen(lang: A): Unit = { 
    language = lang 
    } 

    def displayMessage(msg: String): Unit = { 
    println(language messages msg) 
    } 

} 

我关心的是我怎么能建立一个配置生成器（我指的C++术语）配置此组件？至少有任何参考？或者另一种方式，我如何使用配置文件来配置它？

Answer 1

如果你正在寻找一种方式来处理翻译通过配置文件看看Typesafe Config。在这种特殊情况下，你不得不像下面这样：

import scala.collection.mutable.Map 
import com.typesafe.config.Config 
import scala.collection.JavaConverters._ 

//within some object/class/...you got it 
def loadMessages(config: Config, lang: String): Map[String, String] = config.getObject(lang).asScala map { case (k, v) => k -> v.unwrapped.toString } 

您的配置文件会包含类似以下内容：

translation {  
    english { 
    M01 = "Ready for cooking - press START" 
    M02 = "Close the door to start cooking" 
    } 
    french { 
    M01 = "Pret pour la cuisson - presse START" 
    M02 = "Fermez la porte pour commencer la cuisson" 
    } 
} 

然后加载您的配置文件，并得到翻译映射表如下：

val config: Config = // load your config file. See Typesafe Config for details 

val translationCfg = config.getConfig("translation") 

val english = loadMessages(translationCfg, "english") 
val french = loadMessages(translationCfg, "french") 
... 

课程永恒的缘故，你可以尽量避免使用可变Map和var，但这是另一回事。