Description
In this assignment, you are going to implement a Distributed Library Management System
(DLMS) from Assignment 1 in CORBA using Java IDL. In addition to the 3 student
operations (namely- borrowItem, findItem, and returnItem) introduced in Assignment 1,
the following operation needs to be implemented.
● exchangeItem (studentID, newItemID, oldItemID)
A student might invoke this operation to change an item she/he has already borrowed
with another item in any library. In this case, the current_library_server (which
receives the request from the user) first checks whether the user has borrowed the old
item, then checks with the new_library_server (from which the new item has to be
borrowed) whether this new item is available, and if both checks are successful then
atomically lends the new item to the user and returns the old item.
That is, borrow and
return operations should both be successful or none of them should be done. Note that
all these checks, borrow and return operations should be done using UDP/IP messages
as they are server-to-server communications.
In this assignment you are going to develop this modified application in CORBA using
Java IDL. Specifically, do the following:
● Write the Java IDL interface definition for the modified DLMS with all the 7 specified
operations.
● Implement the modified DLMS. You should design a server that maximizes
concurrency. In other words, use proper synchronization that allows multiple users to
correctly perform operations on the same or different records at the same time.
● Test your application by running multiple clients with the 3 servers. Your test cases
should check correct concurrent access of shared data, and the atomicity of
exchangeItem operation.
Your submission will be graded for correct and efficient implementation of all the
operations in addition to correct use and implementation of mutual exclusion in accessing
shared data and proper exploitation of concurrency to achieve high performance.
MARKING SCHEME
[30%] Design Documentation: Describe the techniques you use and your architecture,
including the data structures. Design proper and sufficient test scenarios and
explain what you want to test. Describe the most important/difficult part in this
assignment. You can use UML and text description, but limit the document to 10
pages. Submit the documentation and code electronically by the due date; print the
documentation and bring it to your DEMO.
[70%] DEMO in the Lab: You have to register for a 5–10 minutes demo. Please come to the
lab session and choose your preferred demo time in advance. You cannot demo
without registering, so if you did not register before the demo week, you will lose
40% of the marks. Your demo should focus on the following.
[50%] The correctness of code: Demo your designed test scenarios to illustrate the
correctness of your design. If your test scenarios do not cover all possible
issues, you will lose part of marks up to 40%.
[20%] Questions: You need to answer some simple questions (like what we have
discussed during lab tutorials) during the demo. They can be theoretical
related directly to your implementation of the assignment.
