How to handle the transaction in J2EE 1.4 with plain JDBC

Question

I am developing a hotel booking site. It is a J2EE 1.4 web application and using JSP and JDBC.

I have one method which is responsible to book the hotel rooms.

booking()

And from this method I am calling other four methods

bookRooms()
makePayment()
confirmUserByMail()
confirmUserBySMS()

I am aware that two users can try to book the same room at the same time and in my current system it is possible that two users might end up with the same room.

How should I handle the transaction to avoid this concurrency issue?

It might be very common scenario but I never handled this kind of scenario before, so please guide me.

Answer 1

Easiest way is add locks in your code or use locks provided by database.You can use volatile or other concurrent tools in java.

If the amount of user is not too large,you can use message queue.Visit from user is encapsulated into object, put the object into the queue and wait for process by threads. It's gonna cost a lot of memory space if there are too many users.

I've heard another way called Optimistic lock,but I've never used it in practice,you can try.

ps If the amount of user is very large,perhaps you should use cache like Memcached.Manipulate datas in the memory and map these changes to database later