How to retrieve multiple items from JSON object in one pass

Question

I am trying to retrieve multiple items from the below JSON in the same pass. I wish to retrieve each originatorId and message for each instance of "sequence" into an ordered format so i can display them in a recycler view like a messaging history.

So far i have already tried to use pattern matching via Klaxon but am unable to get it to pick out more than one instance of "message". I think my issue is finding a way to get each instance of the "change" object instead of just the first one e.g=

"$.body.changes.event.message" -> does not work
"$.body.changes[0].event.message" -> returns only first message

{
    "kind": "notification",
    "body":
    {
        "changes": [
                {
                    "sequence": 0,
                    "originatorId": "d5305f84f7812530e746a713ebeabb457e59b380b779387de90ff0f7ff593e2a",
                    "originatorMetadata":
                    {
                        "id": "d5305f84f7812530e746a713ebeabb457e59b380b779387de90ff0f7ff593e2a",
                        "role": "CONSUMER"
                    },
                    "serverTimestamp": 1555330963355,
                    "event":
                    {
                        "type": "ContentEvent",
                        "message": "hello ",
                        "contentType": "text/plain"
                    },
                    "dialogId": "8e35bc87-c42f-4a28-837d-ac6d93cb119a"
                },
                {
                    "sequence": 2,
                    "originatorId": "73c29cd1-b3e3-56fc-a483-ba3409831d21",
                    "originatorMetadata":
                    {
                        "id": "73c29cd1-b3e3-56fc-a483-ba3409831d21",
                        "role": "ASSIGNED_AGENT"
                    },
                    "serverTimestamp": 1555330964870,
                    "event":
                    {
                        "type": "ContentEvent",
                        "message": "Hi Bob, how can I help you today? 😀",
                        "contentType": "text/plain"
                    },
                    "dialogId": "8e35bc87-c42f-4a28-837d-ac6d93cb119a"
                },
                {
                    "sequence": 3,
                    "originatorId": "d5305f84f7812530e746a713ebeabb457e59b380b779387de90ff0f7ff593e2a",
                    "originatorMetadata":
                    {
                        "id": "d5305f84f7812530e746a713ebeabb457e59b380b779387de90ff0f7ff593e2a",
                        "role": "CONSUMER"
                    },
                    "serverTimestamp": 1555330975711,
                    "event":
                    {
                        "type": "ContentEvent",
                        "message": "hi",
                        "contentType": "text/plain"
                    },
                    "dialogId": "8e35bc87-c42f-4a28-837d-ac6d93cb119a"
                }

My expected results would be some form of map with originatorId to message with the mapping position linked to sequence. At the moment i can only get the first message "hello" out and the last originatorId linked together. further work would include getting out the serverTimestamp into the same mapping as well. I am open to using different libraries to Klaxon.

This is the code i have attempted to use already=

 val pathMatcher = object : PathMatcher {
                override fun pathMatches(path: String) = Pattern.matches(".*.message", path)

                override fun onMatch(path: String, value: Any) {

                    val origin = parseForOriginatorId(text)
                    val messageNew = Message(origin, timeReadNew, value.toString())

                    ChatActivity.adapter.addMessage(Message(origin, timeReadNew, value.toString()))
                    //messages[origin] = messageNew

                    Log.d("D", "Message: ${messageNew.originator}: ${messageNew.content}")

                    when (path) {
                        "$.body.changes.originatorId" -> Log.d("D", "======originator ID $value" )
                        "$.body.changes.event.message" -> Log.d("D", "=====Message $value")
                    }
                }
            }

            Klaxon().pathMatcher(pathMatcher)
                    .parseJsonObject(StringReader(text))
        }

Are you familiar with the GSON library? It does all the parsing for you automatically and gives you a Java object where you can access it easily. Check this answer: stackoverflow.com/a/55724722/8086424 — Mena
– Mena, Commented Apr 17, 2019 at 9:55
GSON helped me a lot, if you submit it as an answer i will accept it — Tristan O'Keefe
– Tristan O'Keefe, Commented Apr 18, 2019 at 8:36

nKalai · Accepted Answer · 2019-04-17 09:45:11Z

1

Loop through the array (an example)

 val myJsonArray = json.get("changes") as JSONArray

 for (i in 0..(myJsonArray.length() - 1)) {
     val item = myJsonArray[i] as JSONObject
 }

answered Apr 17, 2019 at 9:45

nKalai

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