Amazon DynamoDB transactions ile birden çok kayıtta koordineli değişiklikler yapma

private static void createTable(String tableName) {
 try {
     // Create a table with a primary hash key named 'Id', which holds a string
     CreateTableRequest createTableRequest = new CreateTableRequest().withTableName(tableName)
         .withKeySchema(new KeySchemaElement().withAttributeName("Id").withKeyType(KeyType.HASH))
         .withAttributeDefinitions(new AttributeDefinition().withAttributeName("Id").withAttributeType(ScalarAttributeType.S))
         .withProvisionedThroughput(new ProvisionedThroughput().withReadCapacityUnits(1L).withWriteCapacityUnits(1L));

     // Create table if it does not exist yet
     TableUtils.createTableIfNotExists(dynamoDB, createTableRequest);

     // wait for the table to move into ACTIVE state
     TableUtils.waitUntilActive(dynamoDB, tableName);
     
     // Describe our new table
     DescribeTableRequest describeTableRequest = new DescribeTableRequest().withTableName(tableName);
     TableDescription tableDescription = dynamoDB.describeTable(describeTableRequest).getTable();
     System.out.println("Table Created Successfully. Table Description: " + tableDescription);
     
 } catch (InterruptedException e) {
     System.out.println("Occupied thread is interrupted");
 }
}

    private static void createReservation() {
 
 // Create guest item
 HashMap<String, AttributeValue> guestItem = new HashMap<String, AttributeValue>();
 guestItem.put("Id", new AttributeValue("John"));
 guestItem.put("ActiveReservations", new AttributeValue("500"));
 
 // Create room item
 HashMap<String, AttributeValue> roomItem = new HashMap<String, AttributeValue>();
 roomItem.put("Id", new AttributeValue("R20014"));
 roomItem.put("RoomStatus", new AttributeValue("FREE"));
 
 // Create reservation item
 HashMap<String, AttributeValue> reservationItem = new HashMap<String, AttributeValue>();
 reservationItem.put("Id", new AttributeValue("500"));
 reservationItem.put("GuestId", new AttributeValue("John"));
 reservationItem.put("ReservationStatus", new AttributeValue("PENDING"));

 Put createGuest = new Put().withTableName(TABLE_NAME).withItem(guestItem);
 Put createRoom = new Put().withTableName(TABLE_NAME).withItem(roomItem);
 Put createReservation = new Put().withTableName(TABLE_NAME).withItem(reservationItem);

 Collection<TransactWriteItem> actions = Arrays.asList(
         new TransactWriteItem().withPut(createGuest),
         new TransactWriteItem().withPut(createRoom),
         new TransactWriteItem().withPut(createReservation));
 
 TransactWriteItemsRequest createReservationTransaction = new TransactWriteItemsRequest()
         .withTransactItems(actions)
         .withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL);

 // Execute the transaction and process the result.
 // The following code snippet illustrates how to execute the actions defined previously as a single all-or-nothing operation
 dynamoDB.transactWriteItems(createReservationTransaction);
 System.out.println("Create Reservation transaction is successful");
}

    private static void checkIn() {
 
 //Create updateGuest object
 HashMap<String, AttributeValue> guestItemKey = new HashMap<String, AttributeValue>();
 guestItemKey.put("Id", new AttributeValue("John"));
 
 HashMap<String, AttributeValue> guestExpressionAttributeValues = new HashMap<String, AttributeValue>();
 guestExpressionAttributeValues.put(":occupies_rooms", new AttributeValue("R20014"));
 
 Update updateGuest = new Update()
         .withTableName(TABLE_NAME)
         .withKey(guestItemKey)
         .withUpdateExpression("SET OccupiesRooms = :occupies_rooms")
         .withExpressionAttributeValues(guestExpressionAttributeValues);

 
 //Create updateRoom object
 HashMap<String, AttributeValue> roomItemKey = new HashMap<String, AttributeValue>();
 roomItemKey.put("Id", new AttributeValue("R20014"));
 
 HashMap<String, AttributeValue> roomExpressionAttributeValues = new HashMap<String, AttributeValue>();
 roomExpressionAttributeValues.put(":room_status", new AttributeValue("OCCUPIED"));
 roomExpressionAttributeValues.put(":rented_to_reservation", new AttributeValue("500"));
 
 Update updateRoom = new Update()
         .withTableName(TABLE_NAME)
         .withKey(roomItemKey)
         .withUpdateExpression("SET RoomStatus = :room_status, RentedToReservation = :rented_to_reservation")
         .withExpressionAttributeValues(roomExpressionAttributeValues);

 //Create updateReservation object
 HashMap<String, AttributeValue> reservationItemKey = new HashMap<String, AttributeValue>();
 reservationItemKey.put("Id", new AttributeValue("500"));
 
 HashMap<String, AttributeValue> reservationExpressionAttributeValues = new HashMap<String, AttributeValue>();
 reservationExpressionAttributeValues.put(":reservation_status", new AttributeValue("FULLFILLED"));
 reservationExpressionAttributeValues.put(":fullfilled_by_room", new AttributeValue("R20014"));
 
 Update updateReservation = new Update()
         .withTableName(TABLE_NAME)
         .withKey(reservationItemKey)
         .withUpdateExpression("SET ReservationStatus = :reservation_status, FullfilledByRoom = :fullfilled_by_room")
         .withExpressionAttributeValues(reservationExpressionAttributeValues);
 
 //Execute transaction
 Collection<TransactWriteItem> actions = Arrays.asList(
         new TransactWriteItem().withUpdate(updateGuest),
         new TransactWriteItem().withUpdate(updateRoom),
         new TransactWriteItem().withUpdate(updateReservation));
 
 TransactWriteItemsRequest createReservationTransaction = new TransactWriteItemsRequest()
         .withTransactItems(actions)
         .withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL);

 dynamoDB.transactWriteItems(createReservationTransaction);
 System.out.println("Check-in transaction is successful");
 
}

    private static void checkOut() {
 //Create updateGuest object
 HashMap<String, AttributeValue> guestItemKey = new HashMap<String, AttributeValue>();
 guestItemKey.put("Id", new AttributeValue("John"));
 
 Update updateGuest = new Update()
         .withTableName(TABLE_NAME)
         .withKey(guestItemKey)
         .withUpdateExpression("REMOVE OccupiesRooms, ActiveReservations");
 //Since there is no value in the attribute, it is removed
 
 //Create updateRoom object
 HashMap<String, AttributeValue> roomItemKey = new HashMap<String, AttributeValue>();
 roomItemKey.put("Id", new AttributeValue("R20014"));
 
 HashMap<String, AttributeValue> roomExpressionAttributeValues = new HashMap<String, AttributeValue>();
 roomExpressionAttributeValues.put(":room_status", new AttributeValue("FREE"));
 
 Update updateRoom = new Update()
         .withTableName(TABLE_NAME)
         .withKey(roomItemKey)
         .withUpdateExpression("SET RoomStatus = :room_status REMOVE RentedToReservation") //Since there is no value in the attribute, it is removed
         .withExpressionAttributeValues(roomExpressionAttributeValues);
 
 //Create updateReservation object
 HashMap<String, AttributeValue> reservationItemKey = new HashMap<String, AttributeValue>();
 reservationItemKey.put("Id", new AttributeValue("500"));
 
 HashMap<String, AttributeValue> reservationExpressionAttributeValues = new HashMap<String, AttributeValue>();
 reservationExpressionAttributeValues.put(":reservation_status", new AttributeValue("CLOSED"));
 
 Update updateReservation = new Update()
         .withTableName(TABLE_NAME)
         .withKey(reservationItemKey)
         .withUpdateExpression("SET ReservationStatus = :reservation_status")
         .withExpressionAttributeValues(reservationExpressionAttributeValues);
 
 //Execute transaction
 Collection<TransactWriteItem> actions = Arrays.asList(
         new TransactWriteItem().withUpdate(updateGuest),
         new TransactWriteItem().withUpdate(updateRoom),
         new TransactWriteItem().withUpdate(updateReservation));
 
 TransactWriteItemsRequest createReservationTransaction = new TransactWriteItemsRequest()
         .withTransactItems(actions)
         .withReturnConsumedCapacity(ReturnConsumedCapacity.TOTAL);

 dynamoDB.transactWriteItems(createReservationTransaction);
 System.out.println("Check-out transaction is successful");
}