Build a JSON Tree with Recursion

Question

I want to recursively create a JSON tree from multiple strings. A string might like this:

.this.is:0.a.test

The character string is interpreted as follows:

. is an object
: is an array
:0. is the first object in the array

The corresponding JSON looks like this

{
   "this":{
      "is":[
         {
            "a":{
               "test":"testvalue"
            }
         }
      ]
   }
}

My code looks like this:

public static JsonNode recursiveLimb(ArrayList<String> limb, Map<String, String> mappingBodyMap, BidiMap<String, String> bidiMap, JsonNode currentTree, String path) {

        if (!limb.isEmpty() && limb.get(0).equals(".")) {
            //object node

            String firstElem = limb.remove(0);
            String secondElem = limb.remove(0);
            //call recursion to build rest of tree
            JsonNode resultJN = recursiveLimb(limb, mappingBodyMap, bidiMap, currentTree, path + firstElem + secondElem);

            return mapper.createObjectNode().set(secondElem, resultJN);

        } else if (!limb.isEmpty() && limb.get(0).equals(":")) {
            //array node

            String firstElem = limb.remove(0);
            String secondElem = limb.remove(0);
            //call recursion to build rest of tree
            JsonNode resultJN = recursiveLimb(limb, mappingBodyMap, bidiMap, currentTree, path + firstElem + secondElem);

            return mapper.createArrayNode().add(resultJN);

        } else {
            //value node 

            String value = bidiMap.getKey(path);
            return new TextNode(mappingBodyMap.get(value));
        }
    }

This code returns all individual links of the tree. The problem is, I'm having a hard time putting them together. Hopefully someone can help me. Does someone have an idea what I can do?

emredmrcn · Accepted Answer · 2020-02-20 20:58:50Z

1

I think instead of using this it would be easier to create a string and convert it to JSON at the end. Example: .life.is:0.so.good -> We start reading from the end;

We find . we create so:{good=goodValue}
We find :0. is:[{so:{good=goodValue}}]
We find . life:{is:[{so:{good=goodValue}}]}
We find the last . we added {life:{is:[{so:{good=goodValue}}]}}

I believe your solution is good, I just wanted to simplify the problem so it is still up to you.

answered Feb 20, 2020 at 20:58

emredmrcn

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2 Comments

TryHard Over a year ago

Yes sounds good but how do you merge multiple of these jsons in the end?

emredmrcn Over a year ago

GSON-JsonParser would be a good idea. Here is the link for examples, tutorials.jenkov.com/java-json/gson-jsonparser.html

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