COMP 2404 -- Assignment #3

Goal You will modify your movie database program from Assignment #2 and add a serialization class in preparation for
sending movie information across a network. You will also implement a doubly linked list class to hold the movie
information.
Learning Objectives
• begin the adaptation of a repository-style program to a client-server architecture
• learn to format data to send across a network
• gain additional experience with dynamically allocated memory in C++ using linked lists
Instructions:
1. List class
a. Implement a doubly linked list class
You will implement a doubly linked list class (called List) to hold the movies as a collection. You will implement
the linked list exactly as we saw in class, with nodes holding pointers to data (i.e. pointers to Movie objects).
This class should:
• hold pointers to the head and the tail of the list
• provide two add movie functions to add one or more movies to the list
ο one function will take a Movie pointer as a parameter
ο the other function will take a List reference as a parameter
• provide a delete movie function to remove movies from the list
ο one function will take a List reference as a parameter
• manage its memory to avoid memory leaks
• provide any additional utility functions that are required
Notes:
o All collections in your program must be changed to List objects, including the master collection of movies
o Reuse your member functions as much as possible
b. Add an option to the main menu
You will add a new option to the main menu. Option 5 will allow the users to print out the movie list in reverse
order. You should traverse the movie list starting at the tail and moving backwards.
2. Serialization
In a future assignment, you will be separating your program into a server process and a client process, where the
server process manages the persistent storage for multiple clients, while the client process contains the movie
database logic and interacts with the user. However, objects cannot be sent directly between processes. Data that is
transmitted and received over a network using sockets must be formatted as an array of bytes. This means that a
List object and the Movie objects that it contains must be serialized, i.e. transformed into a linear format, in order to
be sent to another process. Similarly, anything that is received from another process must be de-serialized back into a
COMP 2404 -- Assignment #3 Winter 2014 2/3
List object and its contents. There are several conventional forms of serialization, including XML, but the simplest is
string serialization, which we will use in this assignment.
a. Implement the Serializer class
You will add a Serializer class to your program that serializes all communications with the Storage object.
The Serializer class will contain two public member functions:
• void serialize(List& movieList, UpdateType& action, string& serialStr) which takes a
movie list and a type of action (add, delete, or retrieve) and produces the serialized equivalent
• void deserialize(string& serialStr, UpdateType& action, List& movieList) which takes a
serialized string and extracts the corresponding action type and movie list
Each piece of information in the serialized string will be delimited by an asterisk. The format of the serialized string
will be as follows:
• the type of action as a numeric value, followed by an asterisk
• the title, year and numeric genre of the first movie in the list, each followed by an asterisk
• the title, year and numeric genre of the second movie in the list, each followed by an asterisk
• .. and so on until the end of the movie list
For example: a request to add movies “Gravity”, an adventure movie filmed in 2013, and “The Terminator”, an
action flick from 1984, will be serialized as:
0*Gravity*2013*5*The Terminator*1984*2*
where 0 is the numeric value for an “add” action, the title and year of the first movie are followed
by 5 which is the value for the Adventure genre type, followed by the title and year of the second
movie and 2 for the Action genre.
Note: You may use the C++ standard library stringstream class to convert to/from string format, or you can
use the C library functions (sprintf and sscanf). You must not use C functions for any other reason! You can
find a small example program that uses the C functions here.
b. Modify the Storage class
You will add the void handleRequest(string& request, string& reply) function to your Storage
class. This member function does the following:
• takes a serialized request and de-serializes it into action type and movie list
• calls the existing update or retrieve member functions, depending on the action type
• in the case of a retrieve action, handleRequest serializes the master movie list which it returns as the reply
Note: The update and the retrieve member functions do not change from Assignment #2, except that they
become private to the Storage class.
c. Modify the Server façade class
You will modify the update and retrieve functions of your Server façade class to support serialization. Both
functions must do the following:
• serialize the request to be sent to the Storage object
• invoke the handleRequest function on the Storage object
• the retrieve function must also de-serialize the Storage object reply
Note: All communications with the Storage object must be serialized.
COMP 2404 -- Assignment #3 Winter 2014 3/3
Constraints
• your program must be written in C++, and not in C
• do not use any functions from the C standard library (e.g. printf, scanf, fgets, sscanf, malloc, free, string functions)
• do not use any classes or containers from the C++ standard template library (STL)
• do not use low level data types when there is a better one available (e.g. do not use character arrays, use string
objects instead)
• do not use any global variables or any global functions other than main
• do not use structs, use classes instead
• objects should always be passed by reference, not by value
Submission
You will submit in cuLearn, before the due date and time, the following:
• a UML class diagram (as a PDF file) that corresponds to your program design
• one tar file that includes:
ο all source and header files for your movie database program
ο a Makefile
ο a readme file that includes:
 a preamble (program author, purpose, list of source/header/data files)
 compilation, launching and operating instructions
Grading
• Marking breakdown:
Component Marks
UML class diagram 10
List class 30
Serializer class 20
Modifications to Server 25
Modifications to Storage 15
• Deductions:
ο Up to 50 marks for any of the following:
 the code does not compile using g++ in the VM provided for the course
 the code cannot be tested because the program consistently crashes
 the design does not generally follow correct design principles (e.g. data abstraction)
 prohibited library classes or functions are used
ο Up to 20 marks for any of the following:
 the Makefile or readme file is missing
 global variables, global functions, or structs are used
 objects are passed by value
 the code is not correctly separated into header and source files
ο Up to 10 marks for missing comments or other bad style (non-standard indentation, etc.)
• Bonus marks:
ο Up to 5 extra marks are available for fun and creative additional features
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