What is an efficient way to doing this using scala lift?

Question

I want to merge data from one json to another json utilizing scala lift. In the example below, in "jsonGroups", I want to count all the groups "tom" and "dan" are part of and insert the grpCount to "jsonNames". The println(newJson) needs to equal finalOutput. What is an efficient way to do this? I know this can be reduced to much less lines of code

val jsonNames = """
{
    "id" : "1B23423B",
    "payload" : {
        "list" : [ {
                "age" : "30",
                "name" : "tom",
            }, {
                "age" : "35",
                "name" : "dan"
            }]
    }
}
"""

val jsonGroups = """
{
    "id" : "1B23423B",
    "payload" : {
        "list" : [ {
                "group" : "baseball",
                "name" : "tom",
            }, {
                "group" : "basketball",
                "name" : "tom"
            }, {
                "group" : "football",
                "name" : "dan"
            }, {
                "group" : "hockey",
                "name" : "dan"
            }, {
                "group" : "football",
                "name" : "dan"
            }]
    }
}
"""

val finalOutput = """
{
    "id" : "1B23423B",
    "payload" : {
        "list" : [ {
                "age" : "30",
                "name" : "tom",
            "groupCnt" : 2
            }, {
                "age" : "35",
                "name" : "dan",
            "groupCnt" : 3
         }]
    }
}
"""

val jsGroups = parse(jsonGroups)
val groupList = jsGroups \ "payload" \ "list"
val groupMap = new HashMap[String, Int]
groupList.children.foreach { g =>
  val group = (g \ "group").values.toString
  val name = (g \ "name").values.toString
  Option(groupMap.get(name)) match {
    case Some(x) =>
      groupMap.put(name, x + 1)
    case None =>
      groupMap.put(name, 1)
  }
}

val jsNames = parse(jsonNames)   
val newJson = jsNames.transform({
  case dataObject @ JObject(fields) if fields.contains(JField("name", JString(name)))) =>
    val groupCnt = groupMap.get(name)
    dataObject.merge(("groupCnt" -> groupCnt))
})

println (pretty(render(newJson)))

VasiliNovikov · Answer 1 · 2013-12-19T05:34:51.483

0

There might be a lot of ways to do that. What personally I use is case classes. So,

case class JsonGroup(id: String, payload: Payload)
case class Payload(list: List[PayloadList])
case class PayloadList(group: String, name: String)
val groups: Option[JsonGroup] = jsonGroups.extractOpt[JsonGroup]

groups.foreach(group => println(group.payload.list(2).name)

After that you should do your custom logic, of course.

edited Dec 19 '13 at 05:34

answered Dec 18 '13 at 13:03

VasiliNovikov

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I know I can use the merge function, but how do I count the number of times "tom" and "dan" belongs to a group and merge the group count into the first json? – john terran Dec 18 '13 at 16:47
I think the answer's a combination of what can be found here... https://github.com/lift/framework/tree/master/core/json – VasiliNovikov Dec 19 '13 at 14:24

What is an efficient way to doing this using scala lift?

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