Airline Reservation System Dr.Paul Schragger Distributed Systems

1. Airline Reservation SystemDr.Paul SchraggerDistributed Systems Presented By Archana Annamaneni

2. INTRODUCTION • The software used to drive real-world airline reservations is complex. It needs to respond to thousands of simultaneous users and interact with constantly changing flight data. • The airline reservation software developed in this project, only models a small number of transactions • Technology:JAVA RMI

3. PURPOSE • The primary purpose of doing this project is to learn the concepts of distributed systems and to learn JAVA RMI technology. • Transferring data is basic computational operation. Java’s message-method paradigm transfers data from a calling object to a called object within a single Java virtual machine. • We can cross virtual machine boundaries using sockets, to transfer data from one host to another .If we consider both paradigms- method calls and sockets – achieves the same goal: the transfer of data.  • If we consider the two methods, it’s easier to invoke a method than to send a message over a socket. And RMI achieves to send data to a remote host as easily as we invoke a method.

4. Architecture Database

5. USE-CASES • Actor searches for a flight • Actor makes reservation • Actor searches for an active reservation

6. Activity Diagram desired flight exists Actor leaves Actor selects a flight Actor makes reservation Actor searches for a flight Actor looks for active reservation

7. Implementation The following are the three transactions implemented in the project • Search Flights: returns each flight details stored in the database • Book Seat: It does a reservation for a specified passenger and a flight. The transaction makes several simplifying assumptions like the passenger and flight must already exist as entities; the transaction does not create new passengers or flights. It informs if the flight does not exist, and if it does not reserve a seat. • Show Reservation: returns the reservation information for a specific passenger identified by passenger number. It informs if the passenger does not exist

8. Class Diagram

9. Actor Searches For A Flight

10. Actor makes reservation

11. Actor looks for an active reservation

12. Issues Covered Related To DS • Scalability • Concurrency • Openness

13. int theReservationNo = si.lockSeat(theConnection,flight_no ,passenger_no); String query = "Delete From LockedSeat Where ReservationNo ="+theReservationNo; int n = st.executeUpdate(query); int seats = flight.getSeats(); int reservations = flight.getReservations(); if(reservations >=seats)throw new FlightBookedException(); flight.setReservations(reservations+1); flight.dbWrite(db); query ="Insert Into LockedSeat"+"(ReservationN,FlightNo ,PassengerNo,TimeStamp) Values ('"+theReservationNo+"','"+theFlightNo+"','"+thePassengerNo+"','" +new Timestamp(new date())+"')"; int up = st.executeUpdate(query); db.commit(); Reservation res = new Reservation(theReservationNo , flight_no ,passenger_no); int reser = res.dbWrite(theConnection); Flight flight =Flight.getInstance(db,flight_no); Int reservations=flight.getReservations(); Flight.serReservations(reservations-1); Flight.dbWrite(db); db.commit();

14. Key Technology:RMI • RMI Registry A naming service is an application that runs on a central server and functions like a phone book In RMI , the default naming service that ships with JDK is called the RMI Registry Server: serverInterface s = new serverImpl(); Naming.rebind(“rmi://localhost:1099/ARServer”,s); Client: serverInterface theServer =(serverInterface)Naming.lookup(“rmi://localhost/ARServer”)

15. Key Technology Continued…… • theServer.searchFlights() marshal parameters send request unmarshal parameters invoke implementation return Flight[] impl receive return(or exception) marshal return(or exception) skel send reply unmarshal reply stub return value(throw exception)

16. Conclusion • How Important Design and Analysis is? • Real time problems while developing a distributed application • Ways to implement Synchronization