at.ac.tuwien.big.we15.lab2.api.impl.JSONQuestionDataProvider.java Source code

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Here is the source code for at.ac.tuwien.big.we15.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.we15.lab2.api.impl;

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

import at.ac.tuwien.big.we15.lab2.api.Category;
import at.ac.tuwien.big.we15.lab2.api.JeopardyFactory;
import at.ac.tuwien.big.we15.lab2.api.Question;
import at.ac.tuwien.big.we15.lab2.api.QuestionDataProvider;

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 JeopardyFactory factory;

    private Comparator<Question> questionSorter = new Comparator<Question>() {
        @Override
        public int compare(Question q1, Question q2) {
            if (q1 == null || q2 == null)
                throw new IllegalArgumentException("Questions can not be null.");
            return Integer.compare(q1.getValue(), q2.getValue());
        }
    };

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

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

        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;
    }

    protected class CategoryDeserializer implements JsonDeserializer<Category> {

        public static final String MEMBER_NAME = "name";
        public static final String MEMBER_QUESTIONS = "questions";

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

            category.setName(object.get(MEMBER_NAME).getAsString());
            List<Question> questions = new ArrayList<>();

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

            Collections.sort(questions, questionSorter);
            category.setQuestions(questions);
            return category;
        }

    }

    protected class QuestionDeserialzier implements JsonDeserializer<Question> {

        public static final String MEMBER_ID = "id";
        public static final String MEMBER_TEXT = "text";
        public static final String MEMBER_VALUE = "value";
        public static final String MEMBER_WRONG_ANSWERS = "wrongAnswers";
        public static final String MEMBER_RIGHT_ANSWERS = "rightAnswers";

        private int lastChoiceId = 0;

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

            JsonObject object = json.getAsJsonObject();

            Question question = factory.createQuestion();
            question.setId(object.get(MEMBER_ID).getAsInt());
            question.setText(object.get(MEMBER_TEXT).getAsString());

            for (JsonElement wrongAnswer : object.get(MEMBER_WRONG_ANSWERS).getAsJsonArray()) {
                SimpleAnswer answer = context.deserialize(wrongAnswer, new TypeToken<SimpleAnswer>() {
                }.getType());
                answer.setId(lastChoiceId++);
                question.addAnswer(answer, false);
            }

            question.setValue(object.get(MEMBER_VALUE).getAsInt());

            for (JsonElement correctChoice : object.get(MEMBER_RIGHT_ANSWERS).getAsJsonArray()) {
                SimpleAnswer answer = context.deserialize(correctChoice, new TypeToken<SimpleAnswer>() {
                }.getType());
                answer.setId(lastChoiceId++);
                question.addAnswer(answer, true);
            }

            return question;
        }

    }
}