1. Final Project Presentation Distributed Systems (CSC 8530)By
Srinivas Narayanabhatta
25th April 2002

2. Project Description: Title: NSV Book Ordering System.
Developing a distributed “Book Ordering System” application over CORBA platform.
Technologies used:
Server side: Java™, JDBC, MS-Access.
Client side : Java™, Swing.
Object Request Broker : Visibroker for Java™ ORB.

3. UseCases: NSV Book Ordering System
Actors: User, Administrator.
Login to the system
Create user account
View book information of given ISBN
View the entire book list.
Search for a book.
Add a book (administrator)
Process an order
Update book information (administrator).

4. UseCase Diagram

5. Architecture: NSV Book Ordering System
ACCOUNT
SERVER
OBJECT
REQUEST
BROKER
(VISIBROKER ORB)
JDBC
Database
CLIENT
INTERFACE
(SWING)
CORBA
CLIENT
BOOK INFO
SERVER
JDBC
SOAP-CORBA
BRIDGE
HTML
interface
JDBC
CORBA
CLIENT
ORDER
SERVER
CORBA
CLIENT

6. CORBA-IDLs AccountInfoServices.idl BookInfoServices.idl
AccountInfoServicePOA.java
_AccountInfoServiceStub.java
AccountInfoService.java & helpers, holders , exceptions….
BookInfoServices.idl
BookInfoServicePOA.java
_BookInfoServiceStub.java
BookInfoService.java & helpers, holders, exceptions…
OrderServices.idl
OrderServicePOA.java
_OrderServiceStub.java etc…

7. OrderServices Class Diagram

8. Class Diagram

9. CORBA Transactions Client-Controlled Transactions.
Server-Controlled Transactions.
Per-Operation Transaction Model.
Each CORBA remote invocation executes its own transaction. With SQL, each method begins a transaction, issues queries and updates, commits the transaction, and returns to the calling CORBA client.
Phased Transaction Model.
The transaction can span multiple remote invocations, exposing the transaction logic directly to the client.

10. Per-Operation Transaction model.
CORBA client
Application Server
Database
Request
BEGIN
processORder(OrderEntryStruct)
QUERY
Transaction 1
COMMIT
Reply
Request
BEGIN
getOrderInfo(bookId)
QUERY
Transaction 2
COMMIT
Reply

11. Phased Transaction model.
CORBA client
Application Server
Database
Request
BEGIN
getBalance()
QUERY
Reply
Transaction
Request
UPDATE
setBalance()
COMMIT
Reply

12. Sequence Diagram1: Create Account

13. Sequence Diagram1: Search for a book

14. Sequence Diagram1: Order a book.

15. What I learnt
Common Object Request Broker Architecture(CORBA) 3.0’s Portable Object Adapter (POA) and Naming Service.
Understanding CORBA Transaction Services (Object Transaction Service).
Struggling with different implementations of CORB Architecture. E.g. Orbacus(IONA), Oracle, java ORB.
Working with Visibroker for Java™

16. Conclusions
Although per-operation model appears to be simple and of limited usability, it is most widely used transaction models. E.g. Many thousands of HTTP/HTML based applications.
In cases where server-controlled transactions are not sufficient a client-controlled model using the CORBA object transaction service is used.