docs: update transaction script

transaction-script/README.md

@@ -94,9 +94,141 @@ The `bookRoom` method consolidates all the needed steps like checking if the roo
 
 The `cancelRoom` method consolidates steps like checking if the room is booked or not, if booked then calculates the refund amount and updates the database using the DAO.
 
-## Class diagram
+Here is the `App` class with `main` method for running the example.
 
-![Transaction Script](./etc/transaction-script.png "Transaction Script")
+```java
+public class App {
+
+  private static final String H2_DB_URL = "jdbc:h2:mem:testdb;DB_CLOSE_DELAY=-1";
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+  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);
+    }
+  }
+
+  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);
+    }
+  }
+
+  private static List<Room> generateSampleRooms() {
+    final var room1 = new Room(1, "Single", 50, false);
+    final var room2 = new Room(2, "Double", 80, false);
+    final var room3 = new Room(3, "Queen", 120, false);
+    final var room4 = new Room(4, "King", 150, false);
+    final var room5 = new Room(5, "Single", 50, false);
+    final var room6 = new Room(6, "Double", 80, false);
+    return List.of(room1, room2, room3, room4, room5, room6);
+  }
+}
+```
+
+The `App.java` file has the `main` entry point of the application. It demonstrates the use of the Transaction Script pattern in a hotel management context. Here's a step-by-step breakdown of what happens:
+
+1. A new H2 database data source is created using the `createDataSource()` method. This data source is used to interact with the in-memory H2 database.
+
+2. The existing schema (if any) in the database is deleted using the `deleteSchema(dataSource)` method. This is done to ensure a clean state before the application starts.
+
+3. A new schema is created in the database using the `createSchema(dataSource)` method. The schema includes the necessary tables and relationships for the application.
+
+4. An instance of `HotelDaoImpl` is created, which serves as the Data Access Object (DAO). This object is responsible for handling the database operations related to the hotel rooms.
+
+5. Sample rooms are added to the hotel using the `addRooms(dao)` method. This method generates a list of sample rooms and adds them to the hotel via the DAO.
+
+6. The booking status of all rooms is printed using the `getRoomStatus(dao)` method.
+
+7. An instance of `Hotel` is created with the DAO as a parameter. This object represents the hotel and provides methods to book and cancel room bookings.
+
+8. Several rooms are booked using the `hotel.bookRoom(roomNumber)` method.
+
+9. Some of the bookings are then cancelled using the `hotel.cancelRoomBooking(roomNumber)` method.
+
+10. The booking status of all rooms is printed again to reflect the changes.
+
+11. Finally, the schema in the database is deleted again using the `deleteSchema(dataSource)` method, cleaning up the state of the database.
+
+Console output:
+
+```
+14:22:20.050 [main] INFO com.iluwatar.transactionscript.App -- Room(id=1, roomType=Single, price=50, booked=false)
+14:22:20.051 [main] INFO com.iluwatar.transactionscript.App -- Room(id=2, roomType=Double, price=80, booked=false)
+14:22:20.051 [main] INFO com.iluwatar.transactionscript.App -- Room(id=3, roomType=Queen, price=120, booked=false)
+14:22:20.051 [main] INFO com.iluwatar.transactionscript.App -- Room(id=4, roomType=King, price=150, booked=false)
+14:22:20.051 [main] INFO com.iluwatar.transactionscript.App -- Room(id=5, roomType=Single, price=50, booked=false)
+14:22:20.051 [main] INFO com.iluwatar.transactionscript.App -- Room(id=6, roomType=Double, price=80, booked=false)
+14:22:20.058 [main] INFO com.iluwatar.transactionscript.Hotel -- Booking cancelled for room number: 1
+14:22:20.058 [main] INFO com.iluwatar.transactionscript.Hotel -- 50 is refunded
+14:22:20.059 [main] INFO com.iluwatar.transactionscript.Hotel -- Booking cancelled for room number: 3
+14:22:20.059 [main] INFO com.iluwatar.transactionscript.Hotel -- 120 is refunded
+14:22:20.059 [main] INFO com.iluwatar.transactionscript.Hotel -- Booking cancelled for room number: 5
+14:22:20.059 [main] INFO com.iluwatar.transactionscript.Hotel -- 50 is refunded
+14:22:20.060 [main] INFO com.iluwatar.transactionscript.App -- Room(id=1, roomType=Single, price=50, booked=false)
+14:22:20.060 [main] INFO com.iluwatar.transactionscript.App -- Room(id=2, roomType=Double, price=80, booked=true)
+14:22:20.060 [main] INFO com.iluwatar.transactionscript.App -- Room(id=3, roomType=Queen, price=120, booked=false)
+14:22:20.060 [main] INFO com.iluwatar.transactionscript.App -- Room(id=4, roomType=King, price=150, booked=true)
+14:22:20.060 [main] INFO com.iluwatar.transactionscript.App -- Room(id=5, roomType=Single, price=50, booked=false)
+14:22:20.060 [main] INFO com.iluwatar.transactionscript.App -- Room(id=6, roomType=Double, price=80, booked=true)
+```
+
+This pattern is suitable for simple business logic and can be easily understood and maintained.
 
 ## Applicability
 
@@ -105,8 +237,8 @@ The `cancelRoom` method consolidates steps like checking if the room is booked o
 
 ## Tutorials
 
-* [Transaction Script Pattern - DZone](https://dzone.com/articles/transaction-script-pattern#:~:text=Transaction%20Script%20(TS)%20is%20the,need%20big%20architecture%20behind%20them.)
-* [Transaction Script](https://www.informit.com/articles/article.aspx?p=1398617)
+* [Transaction Script Pattern (DZone)](https://dzone.com/articles/transaction-script-pattern#:~:text=Transaction%20Script%20(TS)%20is%20the,need%20big%20architecture%20behind%20them.)
+* [Transaction Script (InformIT)](https://www.informit.com/articles/article.aspx?p=1398617)
 
 ### Known Uses