it.unitn.elisco.dao.AnswerDAO.java Source code

Introduction

Here is the source code for it.unitn.elisco.dao.AnswerDAO.java

Source

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package it.unitn.elisco.dao;

import it.unitn.elisco.bean.hibernate.Answer;
import it.unitn.elisco.bean.hibernate.Context;
import it.unitn.elisco.bean.hibernate.Question;
import it.unitn.elisco.bean.hibernate.Student;
import it.unitn.elisco.utils.HibernateUtil;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;

/**
 *
 * @author Andrea Marcolin
 */
public class AnswerDAO extends DAO<Answer, Long> {

    public void saveAnswer(Student student, Context context, String answer) {
        Session s = HibernateUtil.getSession();
        Transaction tx = s.beginTransaction();

        Answer a = findAnswer(s, student, context);
        if (a != null && a.getBody() == null) {
            a.setBody(answer);
            update(s, a);
        }

        tx.commit();
        s.close();
    }

    public Answer getAnswerByStudentAndContext(Student student, Context context) {
        Session s = HibernateUtil.getSession();
        Transaction tx = s.beginTransaction();

        Answer res = findAnswer(s, student, context);

        tx.commit();
        s.close();

        return res;
    }

    public Answer getAnswerById(Long id) {
        Session s = HibernateUtil.getSession();
        Transaction tx = s.beginTransaction();

        Answer res = getByPrimarykey(s, Answer.class, id);

        tx.commit();
        s.close();

        return res;
    }

    public boolean completedAnswerTask(Student student, Context context) {
        Session s = HibernateUtil.getSession();
        Transaction tx = s.beginTransaction();

        Answer answer = findAnswer(s, student, context);
        boolean res = (answer != null && answer.getBody() != null && !answer.getBody().equals(""));

        tx.commit();
        s.close();

        return res;
    }

    // Only visible to other DAOs
    void assignQuestion(Session s, Student student, Context context, Question question) {
        insertAnswer(s, student, context, question);
    }

    List<Question> getDistinctApprovedQuestionsFromAnswers(Context context) {
        Session s = HibernateUtil.getSession();
        Transaction tx = s.beginTransaction();

        List<Question> res = s.createCriteria(Answer.class).add(Restrictions.eq("context", context))
                .setProjection(Projections.distinct(Projections.property("question"))).list();

        tx.commit();
        s.close();

        return res;
    }

    List<Answer> getAnswersForQuestion(Question question) {
        Session s = HibernateUtil.getSession();
        Transaction tx = s.beginTransaction();

        List<Answer> res = s.createCriteria(Answer.class).add(Restrictions.eq("question", question)).list();

        tx.commit();
        s.close();

        return res;
    }

    // Auxiliary functions 
    private Answer findAnswer(Session s, Student student, Context context) {
        Criteria criteria = s.createCriteria(Answer.class);
        return (Answer) criteria.add(Restrictions.eq("student", student)).add(Restrictions.eq("context", context))
                .uniqueResult();
    }

    private void insertAnswer(Session s, Student student, Context context, Question question) {
        Answer a = new Answer();
        a.setStudent(student);
        a.setContext(context);
        a.setQuestion(question);
        insert(s, a);
    }
}