Merging/ Combining JSON on duplicate nodes using JSON4S

Question

Before any one marks this as duplicate, i've already checked this question: Remove duplicates and merge JSON objects. (copied example from there)

I'm working in on a case that involves merging json like in the example below,

[{
        "id" : 1,
        "name" : "abc",
        "nodes" :[
            {
                "nodeId" : 20,
                "nodeName" : "test1"
            }
        ]
    },
    {
        "id" : 1,
        "name" : "abc",
        "nodes" :[
            {
                "nodeId" : 21,
                "nodeName" : "test2"
            }
        ]
    }]

to something like till the leaf nodes,

 [{
        "id" : 1,
        "name" : "abc",
        "nodes" :[
            {
                "nodeId" : 20,
                "nodeName" : "test1"
            },
            {
                "nodeId" : 21,
                "nodeName" : "test2"
            },
        ]
    }]

I can use the brute force method by recursively comparing nodes and merging manually into an object and finally converting to a json string. I was wondering if there is a better way to do it using json4s. More context, It's a scala project, there are 1000s of json that are to be merged into one and they may have nested complext structes like array and object.

Merging here means adding to pre existing data on duplicate nodes not overwriting them, as in example above.

I've also considered using trees, but not much progress there.

You need to be more clear about the processing that you want doing. What do you mean by "duplicate nodes" and "merging". What data must be the same for two nodes to be duplicates? What data gets merged and how? What if two top-level objects are identical? — Tim
– Tim, Commented Aug 29, 2018 at 15:31
duplicate nodes means common keys on same depth level. merge strategy is shown in example. merging is supposed to happen from root to end nodes. if top key is common, it is kept and child nodes are checked — Chitral Verma
– Chitral Verma, Commented Aug 29, 2018 at 16:15

Valy Dia · Accepted Answer · 2019-07-02 12:33:51Z

You can use the merge operation:

  def main(args: Array[String]): Unit = {

    val json = """[{
                 |        "id" : 1,
                 |        "name" : "abc",
                 |        "nodes" :[
                 |            {
                 |                "nodeId" : 20,
                 |                "nodeName" : "test1"
                 |            }
                 |        ]
                 |    },
                 |    {
                 |        "id" : 1,
                 |        "name" : "abc",
                 |        "nodes" :[
                 |            {
                 |                "nodeId" : 21,
                 |                "nodeName" : "test2"
                 |            }
                 |        ]
                 |    }]""".stripMargin

    val jsonArray = parse(json).asInstanceOf[JArray]
    val res = jsonArray.arr.reduceLeft{(x,y) => x merge y}
    println(pretty(render(res)))

  }

which output:

{
  "id":1,
  "name":"abc",
  "nodes":[{
    "nodeId":20,
    "nodeName":"test1"
  },{
    "nodeId":21,
    "nodeName":"test2"
  }]
}

Collectives™ on Stack Overflow

Merging/ Combining JSON on duplicate nodes using JSON4S

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related