JsonApi Gson Custom Converter

JsonApiConverter.java

package com.travelpath.android.api;

import com.desmart.Inflector;
import com.google.gson.*;
import com.travelpath.android.api.responses.AuthenticateResponse;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;

/**
 * Created by Brodaty on 02.12.2015.
 *
 * //GsonBuilder gsonBuilder = new GsonBuilder();
 * //gsonBuilder.registerTypeAdapter(AuthenticateResponse.class, new CustomDeserializer<>(AuthenticateResponse.class));
 * //Gson gson = gsonBuilder.create();
 */

class CustomDeserializer<T> implements JsonDeserializer<T> {

    private static final String INCLUDED_KEY = "included";
    private static final String RELATIONSHIPS_KEY = "relationships";
    private static final String ATTRIBUTES_KEY = "attributes";
    private static final String TYPE_KEY = "type";
    private static final String ID_KEY = "id";
    private Class<T> mClass;
    private String mKey;
    private JsonElement je;
    private JsonElement includes;

    public CustomDeserializer(Class<T> targetClass) {
        mClass = targetClass;
        mKey = "data";
    }

    @Override
    public T deserialize(JsonElement je, Type type, JsonDeserializationContext jdc)
            throws JsonParseException {
        this.je = je;
        setIncludes();
        JsonElement jsonElement = getBaseJsonElement();

        return new Gson().fromJson(jsonElement, mClass);
    }

    private void setIncludes() {
        includes = this.je.getAsJsonObject().get(INCLUDED_KEY);
        JsonElement newIncludes = new JsonArray();

        for (int i = 0; i < includes.getAsJsonArray().size(); i++) {
            JsonElement jsonElement = includes.getAsJsonArray().get(i);
            jsonElement = getElementWithAttributes(jsonElement);
            addRelations(jsonElement);
            newIncludes.getAsJsonArray().add(jsonElement);
        }

        includes = newIncludes;
    }

    private JsonElement getBaseJsonElement() {
        JsonElement jsonElement = getElementWithAttributes(this.je.getAsJsonObject().get(mKey));
        addRelations(jsonElement);

        return jsonElement;
    }

    private void addRelations(JsonElement jsonElement) {
        if (false == hasRelationshipsKey(jsonElement)) {
            return;
        }

        for (int i = 0; i < includes.getAsJsonArray().size(); i++) {
            addRelation(jsonElement, i);
        }

        jsonElement.getAsJsonObject().remove(RELATIONSHIPS_KEY);
    }

    private void addRelation(JsonElement jsonElement, int i) {
        extractSingleRelationship(jsonElement, i);
        extractManyRelationship(jsonElement, i);
    }

    private void extractManyRelationship(JsonElement jsonElement, int i) {
        Inflector inflector = new Inflector();

        JsonObject relationships = (JsonObject) jsonElement.getAsJsonObject().get(RELATIONSHIPS_KEY);
        String typeString = includes.getAsJsonArray().get(i).getAsJsonObject().get(TYPE_KEY).getAsString();
        String pluralizedTypeString = inflector.pluralize(inflector.camelCase(typeString, false));

        if(relationships.has(pluralizedTypeString)) {
            JsonArray tmpJson = (JsonArray) relationships.get(pluralizedTypeString).getAsJsonObject().get(mKey);

            for (int x = 0; x < tmpJson.getAsJsonArray().size(); x++) {

                addKeyToJsonElement(jsonElement, pluralizedTypeString);

                String tmpElementID = tmpJson.getAsJsonArray().get(x).getAsJsonObject().get(ID_KEY).getAsString();
                String includeId = includes.getAsJsonArray().get(i).getAsJsonObject().get(ID_KEY).getAsString();

                if (tmpElementID.equals(includeId) && false == jsonElement.getAsJsonObject().get(pluralizedTypeString).getAsJsonArray().contains(getElementWithAttributes(includes.getAsJsonArray().get(i)))) {
                    jsonElement.getAsJsonObject().get(pluralizedTypeString).getAsJsonArray().add(getElementWithAttributes(includes.getAsJsonArray().get(i)));
                }
            }
        }
    }

    private void extractSingleRelationship(JsonElement jsonElement, int i) {
        String typeString = includes.getAsJsonArray().get(i).getAsJsonObject().get(TYPE_KEY).getAsString();
        JsonObject relationships = (JsonObject) jsonElement.getAsJsonObject().get(RELATIONSHIPS_KEY);

        if(null != relationships && relationships.has(typeString)) {
            String tmpElementID = relationships.get(typeString).getAsJsonObject().get(mKey).getAsJsonObject().get(ID_KEY).getAsString();
            String includeId = includes.getAsJsonArray().get(i).getAsJsonObject().get(ID_KEY).getAsString();

            if (tmpElementID.equals(includeId)) {
                jsonElement.getAsJsonObject().add(
                        typeString,
                        includes.getAsJsonArray().get(i)
                );
            }
        }
    }

    private boolean hasRelationshipsKey(JsonElement jsonElement) {
        return jsonElement.getAsJsonObject().has(RELATIONSHIPS_KEY);
    }

    private void addKeyToJsonElement(JsonElement jsonElement, String pluralizedTypeString) {
        if (false == jsonElement.getAsJsonObject().has(pluralizedTypeString)) {
            jsonElement.getAsJsonObject().add(pluralizedTypeString, new JsonArray());
        }
    }

    private JsonElement getElementWithAttributes(JsonElement content) {
        JsonElement baseElement = content.getAsJsonObject().get(ATTRIBUTES_KEY);
        baseElement.getAsJsonObject().add(ID_KEY, content.getAsJsonObject().get(ID_KEY));
        baseElement.getAsJsonObject().add(TYPE_KEY, content.getAsJsonObject().get(TYPE_KEY));

        if (true == hasRelationshipsKey(content)) {
            baseElement.getAsJsonObject().add(RELATIONSHIPS_KEY, content.getAsJsonObject().get(RELATIONSHIPS_KEY));
        }

        return baseElement;
    }
}