Merge remote-tracking branch 'origin/master'

transaction-script/README.md

@@ -1,30 +1,26 @@
 ---
 layout: pattern
-title: Transaction script
+title: Transaction Script
 folder: transaction-script
 permalink: /patterns/transaction-script/
-categories: Domain logic
+categories: Behavioral
 tags:
  - Data access
 ---
 
 ## Intent
-Transaction script(TS) is mainly used in small applications where nothing complex is done and bigger architecture's are not needed.
+Transaction Script organizes business logic by procedures where each procedure handles a single request from the presentation.
 
 ## Explanation
 Real world example
-> Your need is to be able to book a hotel room and also be able to cancel that booking.
-> 
+> You need to create a hotel room booking system. Since the requirements are quite simple we intend to use the Transaction Script pattern here.
 
 In plain words
-> All logic related to booking a hotel room like checking room availability,
-> calculate rates and update the database is done inside a single transaction script.
-> Similar procedure is also needed for cancelling a room booking and all 
-> that logic will be in another transaction script.
+> Transaction Script organizes business logic into transactions that the system needs to carry out.
 
 Programmatic example
 
-The Hotel class takes care of booking and cancelling a room in a hotel.
+The `Hotel` class takes care of booking and cancelling room reservations.
 
 ```java
 public class Hotel {
@@ -76,7 +72,7 @@ public class Hotel {
 }
 ```
 
-This class has two methods, one for booking and cancelling a room respectively.
+The `Hotel` class has two methods, one for booking and cancelling a room respectively. Each one of them handles a single transaction in the system, making `Hotel` implement the Transaction Script pattern.
 
 ```
 public void bookRoom(int roomNumber);
@@ -94,8 +90,7 @@ if booked then calculates the refund amount and updates the database using the D
 ![alt text](./etc/transaction-script.png "Transaction script model")
 
 ## Applicability
-Use the transaction script model when the application has only a small amount of logic and that
-logic won't be extended in the future.
+Use the Transaction Script pattern when the application has only a small amount of logic and that logic won't be extended in the future.
 
 ## Consequences
 * As the business logic gets more complicated, 

transaction-script/src/main/java/com/ashishtrivedi16/transactionscript/App.java

@@ -23,7 +23,6 @@
 
 package com.ashishtrivedi16.transactionscript;
 
-import java.sql.SQLException;
 import java.util.List;
 import javax.sql.DataSource;
 import org.h2.jdbcx.JdbcDataSource;
@@ -51,8 +50,8 @@ public class TransactionScriptApp {
     addRooms(dao);
 
     getRoomStatus(dao);
-
-    Hotel hotel = new Hotel(dao);
+  
+    var hotel = new Hotel(dao);
 
     hotel.bookRoom(1);
     hotel.bookRoom(2);
@@ -77,7 +76,7 @@ public class TransactionScriptApp {
     }
   }
 
-  private static void deleteSchema(DataSource dataSource) throws SQLException {
+  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);
@@ -89,7 +88,7 @@ public class TransactionScriptApp {
          var statement = connection.createStatement()) {
       statement.execute(RoomSchemaSql.CREATE_SCHEMA_SQL);
     } catch (Exception e) {
-      throw new CustomException(e.getMessage(), e);
+      throw new SqlException(e.getMessage(), e);
     }
   }
 
@@ -99,7 +98,7 @@ public class TransactionScriptApp {
    * @return h2 datasource
    */
   private static DataSource createDataSource() {
-    JdbcDataSource dataSource = new JdbcDataSource();
+    var dataSource = new JdbcDataSource();
     dataSource.setUrl(H2_DB_URL);
     return dataSource;
   }

transaction-script/src/main/java/com/ashishtrivedi16/transactionscript/Hotel.java

@@ -30,7 +30,7 @@ import org.slf4j.LoggerFactory;
 public class Hotel {
   private static final Logger LOGGER = LoggerFactory.getLogger(TransactionScriptApp.class);
 
-  private HotelDaoImpl hotelDao;
+  private final HotelDaoImpl hotelDao;
 
   public Hotel(HotelDaoImpl hotelDao) {
     this.hotelDao = hotelDao;
@@ -44,7 +44,7 @@ public class Hotel {
    */
   public void bookRoom(int roomNumber) throws Exception {
 
-    Optional<Room> room = hotelDao.getById(roomNumber);
+    var room = hotelDao.getById(roomNumber);
 
     if (room.isEmpty()) {
       throw new Exception("Room number: " + roomNumber + " does not exist");
@@ -52,7 +52,7 @@ public class Hotel {
       if (room.get().isBooked()) {
         throw new Exception("Room already booked!");
       } else {
-        Room updateRoomBooking = room.get();
+        var updateRoomBooking = room.get();
         updateRoomBooking.setBooked(true);
         hotelDao.update(updateRoomBooking);
       }
@@ -66,14 +66,14 @@ public class Hotel {
    * @throws Exception if any error
    */
   public void cancelRoomBooking(int roomNumber) throws Exception {
-
-    Optional<Room> room = hotelDao.getById(roomNumber);
+  
+    var room = hotelDao.getById(roomNumber);
 
     if (room.isEmpty()) {
       throw new Exception("Room number: " + roomNumber + " does not exist");
     } else {
       if (room.get().isBooked()) {
-        Room updateRoomBooking = room.get();
+        var updateRoomBooking = room.get();
         updateRoomBooking.setBooked(false);
         int refundAmount = updateRoomBooking.getPrice();
         hotelDao.update(updateRoomBooking);

transaction-script/src/main/java/com/ashishtrivedi16/transactionscript/HotelDaoImpl.java

@@ -26,7 +26,6 @@ package com.ashishtrivedi16.transactionscript;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.sql.SQLException;
 import java.util.Optional;
 import java.util.Spliterator;
 import java.util.Spliterators;
@@ -48,7 +47,7 @@ public class HotelDaoImpl implements HotelDao {
     try {
       var connection = getConnection();
       var statement = connection.prepareStatement("SELECT * FROM ROOMS");
-      ResultSet resultSet = statement.executeQuery(); // NOSONAR
+      var resultSet = statement.executeQuery(); // NOSONAR
       return StreamSupport.stream(new Spliterators.AbstractSpliterator<Room>(Long.MAX_VALUE,
           Spliterator.ORDERED) {
 
@@ -60,7 +59,7 @@ public class HotelDaoImpl implements HotelDao {
             }
             action.accept(createRoom(resultSet));
             return true;
-          } catch (SQLException e) {
+          } catch (Exception e) {
             throw new RuntimeException(e); // NOSONAR
           }
         }
@@ -71,8 +70,8 @@ public class HotelDaoImpl implements HotelDao {
           e.printStackTrace();
         }
       });
-    } catch (SQLException e) {
-      throw new CustomException(e.getMessage(), e);
+    } catch (Exception e) {
+      throw new SqlException(e.getMessage(), e);
     }
   }
 
@@ -90,8 +89,8 @@ public class HotelDaoImpl implements HotelDao {
       } else {
         return Optional.empty();
       }
-    } catch (SQLException ex) {
-      throw new CustomException(ex.getMessage(), ex);
+    } catch (Exception ex) {
+      throw new SqlException(ex.getMessage(), ex);
     } finally {
       if (resultSet != null) {
         resultSet.close();
@@ -113,8 +112,8 @@ public class HotelDaoImpl implements HotelDao {
       statement.setBoolean(4, room.isBooked());
       statement.execute();
       return true;
-    } catch (SQLException ex) {
-      throw new CustomException(ex.getMessage(), ex);
+    } catch (Exception ex) {
+      throw new SqlException(ex.getMessage(), ex);
     }
   }
 
@@ -130,8 +129,8 @@ public class HotelDaoImpl implements HotelDao {
       statement.setBoolean(3, room.isBooked());
       statement.setInt(4, room.getId());
       return statement.executeUpdate() > 0;
-    } catch (SQLException ex) {
-      throw new CustomException(ex.getMessage(), ex);
+    } catch (Exception ex) {
+      throw new SqlException(ex.getMessage(), ex);
     }
   }
 
@@ -141,12 +140,12 @@ public class HotelDaoImpl implements HotelDao {
          var statement = connection.prepareStatement("DELETE FROM ROOMS WHERE ID = ?")) {
       statement.setInt(1, room.getId());
       return statement.executeUpdate() > 0;
-    } catch (SQLException ex) {
-      throw new CustomException(ex.getMessage(), ex);
+    } catch (Exception ex) {
+      throw new SqlException(ex.getMessage(), ex);
     }
   }
 
-  private Connection getConnection() throws SQLException {
+  private Connection getConnection() throws Exception {
     return dataSource.getConnection();
   }
 
@@ -156,12 +155,12 @@ public class HotelDaoImpl implements HotelDao {
       resultSet.close();
       statement.close();
       connection.close();
-    } catch (SQLException e) {
-      throw new CustomException(e.getMessage(), e);
+    } catch (Exception e) {
+      throw new SqlException(e.getMessage(), e);
     }
   }
 
-  private Room createRoom(ResultSet resultSet) throws SQLException {
+  private Room createRoom(ResultSet resultSet) throws Exception {
     return new Room(resultSet.getInt("ID"),
         resultSet.getString("ROOM_TYPE"),
         resultSet.getInt("PRICE"),

transaction-script/src/main/java/com/ashishtrivedi16/transactionscript/SqlException.java

@@ -26,18 +26,18 @@ package com.ashishtrivedi16.transactionscript;
 /**
  * Custom exception.
  */
-public class CustomException extends Exception {
+public class SqlException extends Exception {
 
   private static final long serialVersionUID = 1L;
 
-  public CustomException() {
+  public SqlException() {
   }
 
-  public CustomException(String message) {
+  public SqlException(String message) {
     super(message);
   }
 
-  public CustomException(String message, Throwable cause) {
+  public SqlException(String message, Throwable cause) {
     super(message, cause);
   }
 }

transaction-script/src/test/java/com/ashishtrivedi16/transactionscript/HotelTest.java

@@ -28,7 +28,6 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import javax.sql.DataSource;
-import java.sql.SQLException;
 import java.util.List;
 
 import static org.junit.jupiter.api.Assertions.*;
@@ -103,7 +102,7 @@ public class HotelTest {
   }
 
 
-  private static void deleteSchema(DataSource dataSource) throws SQLException {
+  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);
@@ -115,7 +114,7 @@ public class HotelTest {
          var statement = connection.createStatement()) {
       statement.execute(RoomSchemaSql.CREATE_SCHEMA_SQL);
     } catch (Exception e) {
-      throw new CustomException(e.getMessage(), e);
+      throw new SqlException(e.getMessage(), e);
     }
   }