Recursively traverse through json adding a name/value pair to each Object

Question

My json looks something like this but a lot more nodes/children:

[{"text":"Millions", "children":[
{"text":"Dinosaur", "children":[{"text":"Stego"}]}, 
{"text":"Dinosaur", "children": [{"text":"T-REX"}]}]}]

I'm trying to recursively go through all the children and add a name/value ("checked": false) pair to the json so that it would now look like:

[{"text":"Millions", "checked": false, "children":[
{"text":"Dinosaur", "checked": false, "children":[{"text":"Stego", "checked": false,}]}, 
{"text":"Dinosaur", "checked": false, "children": [{"text":"T-REX", "checked": false,}]}]}]

What I've come up with so far is:

JSONArray jArrayChecked = new JSONArray();

//This traverses through the nodes
public void addChecked(JSONArray ja){
  for(JSONObject jo : ja){
    if(jo.has("children")
      addChecked(jo.get("children");

    jo.put("checked", false);
    //This part is incorrect
    jArrayChecked.put(jo);
  }
}

How can I properly add the name/value pairs to each node while keeping the node structure intact?

Answer 1

I don't understand the problem. This works for me

public static void addChecked(JSONArray ja) throws JSONException {
    for (int i = 0; i < ja.length(); i++) {
        JSONObject jo = (JSONObject) ja.get(i);
        if (jo.has("children"))
            addChecked((JSONArray) jo.get("children"));

        jo.put("checked", false);
    }
}

public static void main(String[] args) throws Exception {
    String jsonString = "[{\"text\":\"Millions\", \"children\":[{\"text\":\"Dinosaur\", \"children\":[{\"text\":\"Stego\"}]}, {\"text\":\"Dinosaur\", \"children\": [{\"text\":\"T-REX\"}]}]}]";
    JSONArray jsonArray = new JSONArray(jsonString);
    System.out.println(jsonString);
    addChecked(jsonArray);
    System.out.println(jsonArray);
}

It prints

[{"text":"Millions", "children":[{"text":"Dinosaur", "children":[{"text":"Stego"}]}, {"text":"Dinosaur", "children": [{"text":"T-REX"}]}]}]
[{"text":"Millions","children":[{"text":"Dinosaur","children":[{"text":"Stego","checked":false}],"checked":false},{"text":"Dinosaur","children":[{"text":"T-REX","checked":false}],"checked":false}],"checked":false}]

You're manipulating the underlying JSONObjects directly, so no need to reflect the changes in some new JSONArray.

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The solution I've proposed relies heavily on the format of the JSON provided. Keep that in mind if your JSON changes.