at.ac.tuwien.big.we14.lab2.api.impl.JSONQuestionDataProvider.java Source code

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Here is the source code for at.ac.tuwien.big.we14.lab2.api.impl.JSONQuestionDataProvider.java

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/**
 * <copyright>
 *
 * Copyright (c) 2014 http://www.big.tuwien.ac.at All rights reserved. This
 * program and the accompanying materials are made available under the terms of
 * the Eclipse Public License v1.0 which accompanies this distribution, and is
 * available at http://www.eclipse.org/legal/epl-v10.html
 *
 * </copyright>
 */
package at.ac.tuwien.big.we14.lab2.api.impl;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.Type;
import java.util.List;

import at.ac.tuwien.big.we14.lab2.api.Category;
import at.ac.tuwien.big.we14.lab2.api.Question;
import at.ac.tuwien.big.we14.lab2.api.QuestionDataProvider;
import at.ac.tuwien.big.we14.lab2.api.QuizFactory;

import com.google.common.base.Charsets;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.reflect.TypeToken;

public class JSONQuestionDataProvider implements QuestionDataProvider {

    private InputStream inputStream;
    private QuizFactory factory;

    public JSONQuestionDataProvider(InputStream inputStream, QuizFactory factory) {
        this.inputStream = inputStream;
        this.factory = factory;
    }

    @Override
    public List<Category> loadCategoryData() {
        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.registerTypeAdapter(Category.class, new CategoryDeserializer(factory));

        gsonBuilder.registerTypeAdapter(Question.class, new QuestionDeserialzier(factory));

        Gson gson = gsonBuilder.create();

        Type collectionType = new TypeToken<List<Category>>() {
        }.getType();
        List<Category> categories = gson.fromJson(new InputStreamReader(inputStream, Charsets.UTF_8),
                collectionType);

        return categories;
    }

}

class CategoryDeserializer implements JsonDeserializer<Category> {

    private QuizFactory factory;

    public CategoryDeserializer(QuizFactory factory) {
        this.factory = factory;
    }

    @Override
    public Category deserialize(JsonElement json, Type type, JsonDeserializationContext context)
            throws JsonParseException {
        Category category = factory.createCategory();
        JsonObject object = json.getAsJsonObject();

        category.setName(object.get("name").getAsString());

        for (JsonElement jsonquestion : object.get("questions").getAsJsonArray()) {
            Question question = context.deserialize(jsonquestion, new TypeToken<Question>() {
            }.getType());
            category.addQuestion(question);
        }

        return category;
    }

}

class QuestionDeserialzier implements JsonDeserializer<Question> {

    private QuizFactory factory;

    private int lastChoiceId = 0;

    public QuestionDeserialzier(QuizFactory factory) {
        this.factory = factory;
    }

    @Override
    public Question deserialize(JsonElement json, Type type, JsonDeserializationContext context)
            throws JsonParseException {

        Question question = factory.createQuestion();

        JsonObject object = json.getAsJsonObject();
        question.setId(object.get("id").getAsInt());
        question.setText(object.get("text").getAsString());

        for (JsonElement wrongChoice : object.get("wrongChoices").getAsJsonArray()) {
            SimpleChoice choice = context.deserialize(wrongChoice, new TypeToken<SimpleChoice>() {
            }.getType());
            choice.setId(lastChoiceId++);
            question.addChoice(choice, false);
        }

        question.setMaxTime(object.get("maxTime").getAsLong());

        for (JsonElement correctChoice : object.get("correctChoices").getAsJsonArray()) {
            SimpleChoice choice = context.deserialize(correctChoice, new TypeToken<SimpleChoice>() {
            }.getType());
            choice.setId(lastChoiceId++);
            question.addChoice(choice, true);
        }

        return question;
    }

}