merge.scala

  type ParsedDoc = Map[String, Any]
  type PartialDoc = (UID, ParsedDoc)

  /**
   * Recursively merge two parsed json documents
   */
  private def merge(map1 : ParsedDoc, map2 : ParsedDoc): ParsedDoc = {
    def mergeValues(o1 : Option[Any], o2 : Option[Any]) =
      (o1, o2) match {
        case (Some(v1 : ParsedDoc), Some(v2 : ParsedDoc)) => merge(v1, v2)
        case _ => (o1 orElse o2).get
      }

    (map1.keySet ++ map2.keySet)
      .map(key => key -> mergeValues(map1.get(key), map2.get(key)))
      .toMap
  }