service.ProblemService.java Source code

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Here is the source code for service.ProblemService.java

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/*
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package service;

import hibernate.HibernateUtil;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import model.Platform;
import model.Problem;
import model.ProblemInfo;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.SQLQuery;
import org.hibernate.Session;
import org.hibernate.Transaction;

/**
 *
 * @author Dhaval
 */
public class ProblemService {

    public static List<ProblemInfo> getProblems(List<Integer> platforms, List<String> tags) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        String sql = "SELECT id, title, platform, problem_url from problem ";

        boolean emptyPlatform = true;
        boolean emptyTags = true;

        if (platforms != null && platforms.size() > 0) {
            emptyPlatform = false;
            sql += "where platform in(:platforms)";
        }

        if (tags != null && tags.size() > 0) {
            emptyTags = false;

            if (emptyPlatform) {
                sql += "where ";
            } else {
                sql += "and ";
            }

            sql += "id in(select id from tags where tag_name in (:tags))";
        }

        SQLQuery query = session.createSQLQuery(sql);

        if (!emptyPlatform) {
            query.setParameterList("platforms", platforms);
        }
        if (!emptyTags) {
            query.setParameterList("tags", tags);
        }

        List result = query.list();
        List<ProblemInfo> problems = new ArrayList<>();

        for (Iterator iterator = result.iterator(); iterator.hasNext();) {
            Object[] objects = (Object[]) iterator.next();
            int id = (Integer) objects[0];
            String title = (String) objects[1];
            Platform platform = Platform.fromOrdinal((Integer) objects[2]);
            String problemUrl = (String) objects[3];
            ProblemInfo problemInfo = new ProblemInfo(id, title, platform, problemUrl);
            problems.add(problemInfo);
        }

        session.close();
        return problems;
    }

    public static Problem getProblem(int id) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        Problem problem = (Problem) session.get(Problem.class, id);
        session.close();
        return problem;
    }

    public static Problem addProblem(Problem problem) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction transaction = session.getTransaction();
        transaction.begin();
        int id = (Integer) session.save(problem);
        transaction.commit();
        session.close();
        problem.setId(id);
        return problem;
    }

    public static Problem updateProblem(Problem problem) {
        Session session = HibernateUtil.getSessionFactory().openSession();
        Transaction transaction = session.getTransaction();
        transaction.begin();
        Problem problem1 = (Problem) session.get(Problem.class, problem.getId());
        problem1.getSampleInputOutputs().clear();
        problem1.getSampleInputOutputs().addAll(problem.getSampleInputOutputs());
        session.update(problem1);
        transaction.commit();
        transaction = session.beginTransaction();
        problem1.setConstraints(problem.getConstraints());
        problem1.setExplanation(problem.getExplanation());
        problem1.setInputFormat(problem.getInputFormat());
        problem1.setOutputFormat(problem.getOutputFormat());
        problem1.setPlatform(problem.getPlatform());
        problem1.setProblemStatement(problem.getProblemUrl());
        problem1.setProblemUrl(problem.getProblemUrl());
        problem1.setTimeLimit(problem.getTimeLimit());
        problem1.setTitle(problem.getTitle());
        problem1.setTags(problem.getTags());
        session.update(problem1);
        transaction.commit();
        session.close();
        return problem;
    }

    public static void deleteProblem(int id) {
        Session session = null;
        Transaction transaction = null;
        try {
            session = HibernateUtil.getSessionFactory().openSession();
            transaction = session.beginTransaction();
            Problem problem = (Problem) session.get(Problem.class, id);
            if (problem == null) {
                throw new IllegalArgumentException("Invalid id " + id);
            }
            String hql = "delete " + Problem.class.getName() + " where id = :id";
            Query query = session.createQuery(hql).setParameter("id", id);
            query.executeUpdate();
            transaction.commit();
        } catch (HibernateException e) {
            if (transaction != null) {
                transaction.rollback();
            }

            throw new RuntimeException(e);
        } finally {
            if (session != null) {
                session.close();
            }
        }
    }
}