Bubble Sorting Java Strings stored in JSONArray

Question

I have a JSON file saved on disk that looks like this:

{
  "author": [
    "Mario Vargas Llosa",
    "Maria Duenas",
    "Liviu Rebreanu",
    "Liviu Rebreanu"
  ],
  "nameBook": [
    "Eroul discret",
    "Iubirile croitoresei",
    "Ion",
    "Ion"
  ],
  "priceBook": [
    34,
    28,
    40,
    40
  ],
  "publisherBook": [
    "Humanitas",
    "Polirom",
    "Humanitas",
    "Dacia"
  ],
  "idBook": [
    1,
    2,
    3,
    4
  ]
}

Then I have the following Java code:

// read the json file
FileReader reader = new FileReader(filePath);

JSONParser jsonParser = new JSONParser();
JSONObject jsonObject = (JSONObject) jsonParser.parse(reader);

// get a String from the JSON object

JSONArray idBookJ =  (JSONArray) jsonObject.get("idBook");
JSONArray nameBookJ = (JSONArray) jsonObject.get("nameBook");
JSONArray authorJ = (JSONArray) jsonObject.get("author");
JSONArray publisherBookJ = (JSONArray) jsonObject.get("publisherBook");
JSONArray priceBookJ = (JSONArray) jsonObject.get("priceBook");

Now I need to sort the content from the publisherBook tag alphabetically, after the first letter of the word, using Bubble Sort. I know this isn't the most amazing programming challenge, but I got stuck at treating the strings from the JSONArray as... Strings.

Answer 1

This solution worked for me, but I will still post the code just in case. It is not pure Bubble Sort, but it's better than almost nothing.

The JSON array:

[
   {
      "firstName":"John",
      "lastName":"Doe"
   },
   {
      "firstName":"Anna",
      "lastName":"Smith"
   },
   {
      "firstName":"Peter",
      "lastName":"Jones"
   }
]

The JSON Simple library is available here:

package com.iglooworks.test;
    import org.json.simple.JSONArray;
    import org.json.simple.JSONObject;

    import java.util.Set;
    import java.util.SortedMap;
    import java.util.TreeMap;

    public class JsonSorter {
        public static JSONArray sortJsonByKey(JSONArray json, String key)
        {
            JSONArray sorted = new JSONArray();
            SortedMap map = new TreeMap();

            for (Object o : json) {
                JSONObject tmp = (JSONObject) o;
                map.put(tmp.get(key),tmp);
            }

            Set<String> numbers = map.keySet();

            for (String number : numbers) {
                sorted.add(map.get(number));
            }

            return sorted;
        }

}

The usage seems to be very simple:

package com.iglooworks.test;

import com.iglooworks.tools.JsonSorter;
import org.json.simple.*;

public class Test {
    public static void main(String[] args) {
                String json = "[\n" +
                "   {\n" +
                "      \"firstName\":\"John\",\n" +
                "      \"lastName\":\"Doe\"\n" +
                "   },\n" +
                "   {\n" +
                "      \"firstName\":\"Anna\",\n" +
                "      \"lastName\":\"Smith\"\n" +
                "   },\n" +
                "   {\n" +
                "      \"firstName\":\"Peter\",\n" +
                "      \"lastName\":\"Jones\"\n" +
                "   }\n" +
                "]";

        JSONArray jsonArray;
        try {
            jsonArray = tools.sortJsonByKey((JSONArray) JSONValue.parse(json), "firstName");


            for (Object o : jsonArray) {
                JSONObject tmp = (JSONObject) o;
                System.out.println(tmp.get("firstName") + " - " + tmp.get("lastName"));
            }

        } catch (Exception e) {
            e.printStackTrace(); 
        }


    }
}

Final thought: I discovered this solution may lead to NullPointerException, so I will try to improve it when I have time.