command-query-responsibility-segregation/src/main/java/com/iluwatar/cqrs/queries/QueryServiceImpl.java - master - githubmirror/java-design-patterns

command-query-responsibility-segregation/src/main/java/com/iluwatar/cqrs/queries/QueryServiceImpl.java
111 строк4 KB
Ilkka Seppälä
deps: Refactor dependencies (#3224)
29 мар 2025, 20:34
29 мар 2025, 20:340ca162a
/*
 * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
 *
 * The MIT License
 * Copyright © 2014-2022 Ilkka Seppälä
 *
 * 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 com.iluwatar.cqrs.constants.AppConstants;
import com.iluwatar.cqrs.dto.Author;
import com.iluwatar.cqrs.dto.Book;
import com.iluwatar.cqrs.util.HibernateUtil;
import java.math.BigInteger;
import java.util.List;
import org.hibernate.SessionFactory;
import org.hibernate.query.Query;

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

  private final SessionFactory sessionFactory = HibernateUtil.getSessionFactory();

  @Override
  public Author getAuthorByUsername(String username) {
    Author authorDto;
    try (var session = sessionFactory.openSession()) {
      Query<Author> sqlQuery =
          session.createQuery(
              "select new com.iluwatar.cqrs.dto.Author(a.name, a.email, a.username)"
                  + " from com.iluwatar.cqrs.domain.model.Author a where a.username=:username");
      sqlQuery.setParameter(AppConstants.USER_NAME, username);
      authorDto = sqlQuery.uniqueResult();
    }
    return authorDto;
  }

  @Override
  public Book getBook(String title) {
    Book bookDto;
    try (var session = sessionFactory.openSession()) {
      Query<Book> sqlQuery =
          session.createQuery(
              "select new com.iluwatar.cqrs.dto.Book(b.title, b.price)"
                  + " from com.iluwatar.cqrs.domain.model.Book b where b.title=:title");
      sqlQuery.setParameter("title", title);
      bookDto = sqlQuery.uniqueResult();
    }
    return bookDto;
  }

  @Override
  public List<Book> getAuthorBooks(String username) {
    List<Book> bookDtos;
    try (var session = sessionFactory.openSession()) {
      Query<Book> sqlQuery =
          session.createQuery(
              "select new com.iluwatar.cqrs.dto.Book(b.title, b.price)"
                  + " from com.iluwatar.cqrs.domain.model.Author a, com.iluwatar.cqrs.domain.model.Book b "
                  + "where b.author.id = a.id and a.username=:username");
      sqlQuery.setParameter(AppConstants.USER_NAME, username);
      bookDtos = sqlQuery.list();
    }
    return bookDtos;
  }

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

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