Distributed Systems – Mock Exam –

1 Protocols
(i) If you had to implement a protocol for remote method invocation, on which
transport level protocol would you base it, UDP or TCP? Explain your answer.
(5 points)
(ii) Suppose you have to implement a request-reply protocol. For each of the
three, UDP, TCP, and HTTP, discuss whether one could use it as the basis
for the new implementation. Which one would be the most suitable and
which one the least? Why?
(15 points)
2 Java RMI
Suppose a server is to be implemented for a book shop where customers can place
orders and managers can check how many copies of each book have been ordered.
There are two methods to access the server,
1. order, which takes four strings, name, cardNo, bookCode, and address
as arguments, and stores that the customer with that name and the credit
card number cardNo has ordered a copy of the book identified by bookCode
to be sent to address;
2. copiesOrdered, which takes a string bookCode as argument and returns
an integer, representing the number of copies ordered of the book with
code bookCode
(i) Write down the declarations of the interfaces and the classes (including the
method declarations) that have to be implemented on the server side.
(12 points)
(ii) Describe how you would implement a small client program that can be
started from a command shell, with the book code as argument, and returns
the number of copies that have been ordered.
(8 points)
(iii) Which compilation steps have to be made in which order before the client
can be started?
2
(4 points)