KeyValueXml(http://d.hatena.ne.jp/fumokmm/20110315/1300210292)のScala実装。

KeyValueXml.scala

/*
 * Created by IntelliJ IDEA.
 * User: fumokmm
 * Date: 11/03/19
 * Time: 16:09
 */
package jp.scaladojo

import scala.xml._

class KeyValue(key: String, value: Any) {
  val this.key: String = key
  val this.value: Any = value

  override def toString(): String = toXMLString

  def toXMLString: String = {
    val inner: String = this.value match {
      case lst: List[KeyValue] => (for(kv <- lst) yield kv.toXMLString).mkString
      case s  : String         => s
    }
    startTag + inner + endTag
  }
  def startTag = "<" + this.key + ">"
  def endTag = "</" + this.key + ">"
}

object KeyValue {
  def main(args: Array[String]): Unit = {
    val keyValue = new KeyValue("langs", List(
      new KeyValue("key1", "value1"),
      new KeyValue("key2", "value2"),
      new KeyValue("key3", List(
        new KeyValue("key3-1", "value3-1"),
        new KeyValue("key3-2", "value3-2")
      ))
    ))

    val resultXml = XML.loadString(keyValue.toXMLString)
    // Confirmation
    assert(resultXml == <langs><key1>value1</key1><key2>value2</key2><key3><key3-1>value3-1</key3-1><key3-2>value3-2</key3-2></key3></langs>)
    println(resultXml)
  }
}