JSON Objects/Arrays - Java Class

Question

I am currently working on a java class in android studio for a constructor with getters and setters trying to work with JSON arrays and objects. The top code example is my JSON data format and the code underneath is my .JAVA class with the methods but am unsure where I'm going wrong with arrays. How would I make methods to add an ingredient (object), add all ingredients (Array), get one ingredient (object) and get all ingredients? (array)

{"cocktails":[


{
    "cocktail_name": "Apple Martini",
    "cocktail_glass": "Martini",
    "cocktail_ingredients": [
      {
        "amount": 37.5,
        "measurement": "ml",
        "ingredient": "Ketel One Vodka"
      },
      {
        "amount": 12.5,
        "measurement": "ml",
        "ingredient": "Berentzen Apfel Korn"
      },
      {
        "amount": 25,
        "measurement": "ml",
        "ingredient": "Apple Juice"
      }
    ],
    "cocktail_recipe": [
      "first step",
      "second step",
      "third step"
    ],
    "cocktail_description": "Nam ultrices, libero non mattis pulvinar, nulla pede ullamcorper augue, a suscipit nulla elit ac nulla. Sed vel enim sit amet nunc viverra dapibus. Nulla suscipit ligula in lacus.",
    "cocktail_garnish": [
      {
        "amount": 1,
        "measurement": "wedge",
        "ingredient": "Apple"
      }
    ],
    "cocktail_alcoholic": true,
    "cocktail_barware": ["bostin tin","bar spoon","strainer","match/lighter"],
    "cocktail_tags": ["Green","Vodka","Martini","Medium","Ketel One", "Berentzen Apfel Korn", "Liquer", "Apple"],
    "cocktail_img_id": "pic.jpeg",
    "cocktail_video_id": "https://youtu.be/z4yL2xrI0RY"
  }]}




public final class cocktail {
       private String name;
       private String glass;
       private JSONArray ingredients; //this is now a json array
       private String[] recipe;
       private String description;
       private JSONArray garnish; //this is a json array aswell
       private Boolean alcoholic;
       //private Float Abv;
      private String[] barware;
      private String[] tags;
      private String image;
      private String video;

      // constructor
      public cocktail(String name, String glass, JSONArray ingredients,       String[] recipe, String description, JSONArray garnish, Boolean alcoholic, String[] barware, String[] tags, String image, String video) {
      this.name = name;
      this.glass = glass;
      this.ingredients = ingredients;
      this.recipe = recipe;
      this.description = description;
      this.garnish = garnish;
      this.alcoholic = alcoholic;
      //this.Abv = Abv;
      this.barware = barware;
      this.tags = tags;
      this.image = image;
      this.video = video;
      }

      //Get method for grabbing an ingredient from the ingredients list of "this" cocktail //change
     public JSONObject getIngredient(String ingred) {
     JSONArray ingred = this.ingredients;

    ingredientObj = getJSONObject()

    }

//Method for setting an ingredient of index i of "this" cocktail
public void setIngredient(Integer amount, String measurement, String ing) {
    JSONObject ingredientObject = new JSONObject();

    ingredientObject.put("amount",amount);
    ingredientObject.put("measurement",measurement);
    ingredientObject.put("ingredient",ing);

    this.ingredients.add(ingredientObject);
}}

Answer 1

Here is a test class and corresponding code for your situation. It should be fairly simple to add the other fields you're considering. It seems like most of the hangup is in conversion to/from JSON objects and regular Java types.

For something like this, you may want to consider using a library like Jackson to do automatic translation from POJOs to JSON objects.

CocktailTest.java

import org.json.JSONArray;
import org.json.JSONObject;
import org.junit.Test;

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;


public class CocktailTest {

    @Test
    public void addOneIngredient() {
        Cocktail cocktail = new Cocktail();
        cocktail.addIngredient("whiskey", 5);

        assertThat(cocktail.root.toString(), is("{\"ingredients\":[{\"amount\":5,\"name\":\"whiskey\"}]}"));

    }
    @Test
    public void addTwoIngredients() {
        Cocktail cocktail = new Cocktail();
        cocktail.addIngredient("whiskey", 5);
        cocktail.addIngredient("olive", 2);

        assertThat(cocktail.root.toString(), is("{\"ingredients\":[{\"amount\":5,\"name\":\"whiskey\"},{\"amount\":2,\"name\":\"olive\"}]}"));
    }

    @Test
    public void getOneIngredient() {
        Cocktail cocktail = new Cocktail();
        cocktail.addIngredient("whiskey", 5);
        JSONObject ingredient = cocktail.getIngredient("whiskey");

        assertThat(ingredient.get("name"), is("whiskey"));
        assertThat(ingredient.get("amount"), is(5));
    }

    @Test
    public void getAllIngredients() {
        Cocktail cocktail = new Cocktail();
        cocktail.addIngredient("whiskey", 5);
        cocktail.addIngredient("olive", 2);
        JSONArray ingredients = cocktail.getIngredients();

        JSONObject whiskey = ingredients.getJSONObject(0);
        assertThat(whiskey.get("name"), is("whiskey"));
        assertThat(whiskey.get("amount"), is(5));

        JSONObject olive = ingredients.getJSONObject(1);
        assertThat(olive.get("name"), is("olive"));
        assertThat(olive.get("amount"), is(2));
    }
}

Cocktail.java

import org.json.JSONArray;
import org.json.JSONObject;

public class Cocktail {
    public final JSONObject root = new JSONObject();

    public Cocktail() {
       root.put("ingredients", new JSONArray()) ;
    }

    public void addIngredient(String ingredientName, int amount) {

        JSONObject ingredient = new JSONObject();
        ingredient.put("name", ingredientName);
        ingredient.put("amount", amount);
        JSONArray ingredients = (JSONArray) root.get("ingredients");
        ingredients.put(ingredient);
    }

    public JSONObject getIngredient(String ingredientName) {
        JSONArray ingredients = (JSONArray) root.get("ingredients");
        for (Object ingredientObj: ingredients ) {
            JSONObject ingredient = (JSONObject)ingredientObj;
            if (ingredient.get("name").equals(ingredientName)) {
                return ingredient;
            }
        }

        throw new IllegalArgumentException("Couldn't find " + ingredientName);
    }

    public JSONArray getIngredients() {
        return root.getJSONArray("ingredients");
    }
}