/* * The MIT License * Copyright © 2014-2021 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.transactionscript; import java.util.List; import javax.sql.DataSource; import org.h2.jdbcx.JdbcDataSource; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Transaction Script (TS) is one of the simplest domain logic pattern. * It needs less work to implement than other domain logic patterns and therefore * it’s perfect fit for smaller applications that don't need big architecture behind them. * *
In this example we will use the TS pattern to implement booking and cancellation * methods for a Hotel management App. The main method will initialise an instance of * {@link Hotel} and add rooms to it. After that it will book and cancel a couple of rooms * and that will be printed by the logger.
* *The thing we have to note here is that all the operations related to booking or cancelling * a room like checking the database if the room exists, checking the booking status or the * room, calculating refund price are all clubbed inside a single transaction script method.
*/ public class App { private static final String H2_DB_URL = "jdbc:h2:~/test"; private static final Logger LOGGER = LoggerFactory.getLogger(App.class); /** * Program entry point. * Initialises an instance of Hotel and adds rooms to it. * Carries out booking and cancel booking transactions. * @param args command line arguments * @throws Exception if any error occurs */ public static void main(String[] args) throws Exception { final var dataSource = createDataSource(); deleteSchema(dataSource); createSchema(dataSource); final var dao = new HotelDaoImpl(dataSource); // Add rooms addRooms(dao); // Print room booking status getRoomStatus(dao); var hotel = new Hotel(dao); // Book rooms hotel.bookRoom(1); hotel.bookRoom(2); hotel.bookRoom(3); hotel.bookRoom(4); hotel.bookRoom(5); hotel.bookRoom(6); // Cancel booking for a few rooms hotel.cancelRoomBooking(1); hotel.cancelRoomBooking(3); hotel.cancelRoomBooking(5); getRoomStatus(dao); deleteSchema(dataSource); } private static void getRoomStatus(HotelDaoImpl dao) throws Exception { try (var customerStream = dao.getAll()) { customerStream.forEach((customer) -> LOGGER.info(customer.toString())); } } private static void deleteSchema(DataSource dataSource) throws java.sql.SQLException { try (var connection = dataSource.getConnection(); var statement = connection.createStatement()) { statement.execute(RoomSchemaSql.DELETE_SCHEMA_SQL); } } private static void createSchema(DataSource dataSource) throws Exception { try (var connection = dataSource.getConnection(); var statement = connection.createStatement()) { statement.execute(RoomSchemaSql.CREATE_SCHEMA_SQL); } catch (Exception e) { throw new Exception(e.getMessage(), e); } } /** * Get database. * * @return h2 datasource */ private static DataSource createDataSource() { var dataSource = new JdbcDataSource(); dataSource.setUrl(H2_DB_URL); return dataSource; } private static void addRooms(HotelDaoImpl hotelDao) throws Exception { for (var room : generateSampleRooms()) { hotelDao.add(room); } } /** * Generate rooms. * * @return list of rooms */ private static List