com.iluwatar.cqrs.queries.QueryServiceImpl.java Source code

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Here is the source code for com.iluwatar.cqrs.queries.QueryServiceImpl.java

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/**
 * The MIT License
 * Copyright (c) 2014 Ilkka Seppl
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.iluwatar.cqrs.queries;

import java.math.BigInteger;
import java.util.List;

import org.hibernate.SQLQuery;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.transform.Transformers;

import com.iluwatar.cqrs.dto.Author;
import com.iluwatar.cqrs.dto.Book;
import com.iluwatar.cqrs.util.HibernateUtil;

/**
 * This class is an implementation of {@link IQueryService}. It uses Hibernate native queries to return DTOs from the
 * database.
 *
 */
public class QueryServiceImpl implements IQueryService {

    private SessionFactory sessionFactory = HibernateUtil.getSessionFactory();

    @Override
    public Author getAuthorByUsername(String username) {
        Author authorDTo = null;
        try (Session session = sessionFactory.openSession()) {
            SQLQuery sqlQuery = session
                    .createSQLQuery("SELECT a.username as \"username\", a.name as \"name\", a.email as \"email\""
                            + "FROM Author a where a.username=:username");
            sqlQuery.setParameter("username", username);
            authorDTo = (Author) sqlQuery.setResultTransformer(Transformers.aliasToBean(Author.class))
                    .uniqueResult();
        }
        return authorDTo;
    }

    @Override
    public Book getBook(String title) {
        Book bookDTo = null;
        try (Session session = sessionFactory.openSession()) {
            SQLQuery sqlQuery = session.createSQLQuery(
                    "SELECT b.title as \"title\", b.price as \"price\"" + " FROM Book b where b.title=:title");
            sqlQuery.setParameter("title", title);
            bookDTo = (Book) sqlQuery.setResultTransformer(Transformers.aliasToBean(Book.class)).uniqueResult();
        }
        return bookDTo;
    }

    @Override
    public List<Book> getAuthorBooks(String username) {
        List<Book> bookDTos = null;
        try (Session session = sessionFactory.openSession()) {
            SQLQuery sqlQuery = session.createSQLQuery("SELECT b.title as \"title\", b.price as \"price\""
                    + " FROM Author a , Book b where b.author_id = a.id and a.username=:username");
            sqlQuery.setParameter("username", username);
            bookDTos = sqlQuery.setResultTransformer(Transformers.aliasToBean(Book.class)).list();
        }
        return bookDTos;
    }

    @Override
    public BigInteger getAuthorBooksCount(String username) {
        BigInteger bookcount = null;
        try (Session session = sessionFactory.openSession()) {
            SQLQuery sqlQuery = session.createSQLQuery("SELECT count(b.title)"
                    + " FROM  Book b, Author a where b.author_id = a.id and a.username=:username");
            sqlQuery.setParameter("username", username);
            bookcount = (BigInteger) sqlQuery.uniqueResult();
        }
        return bookcount;
    }

    @Override
    public BigInteger getAuthorsCount() {
        BigInteger authorcount = null;
        try (Session session = sessionFactory.openSession()) {
            SQLQuery sqlQuery = session.createSQLQuery("SELECT count(id) from Author");
            authorcount = (BigInteger) sqlQuery.uniqueResult();
        }
        return authorcount;
    }

}