COIT132229 Applied Distributed Systems Assignment 1 – Java Client/Server Application

Objectives

This assessment item is designed to test your understanding in Java TCP networking, Java Object Serialization/Deserialization, threading, file reading and writing using a client/server application development.

Assessment task

CQU aquatic centre offers swim facility to current students and their families. Entry to the swimming centre is accessible through any of the three automatic doors by keying in a registered student number followed by a 4-digit pin code preferably set to the year of birth. Each entry is charged a flat fee and the time should be persisted to a log file with two fields (student number space separated with entry date and time). Because of the flat fee structure, the entry details can be shared among family members. The system should accommodate both existing users with authentication and provide registration for new users. Administrator role is not relevant and will be discussed in the second assignment. The application should be implemented as a client/server model using java TCP sockets. The client program handles all the data entry and menu selections (1. Current Student 2. New Student 3. Exit). Current student should only be prompted for a student number and a pin code. New student registrations should be prompted to provide relevant details (Student number and a Pin Code). Appropriate error messages (Student exists, Un- Registered Student, Invalid Pin, Welcome or Student Created) should be received from the server after processing and displayed on the client. Student number is alphanumeric but cannot be empty. The client should create an instance of relevant type before sending to the server program for processing and storage. Every 3 minutes the contents from the data structures stored on the server need to be persisted to the text files. The server program should have the capability to concurrently handle multiple client connections (Thread-per-connection). Existing records are to be read and loaded from the provided text files (“ studententry.txt ” and  logentry.txt ”). When these text files do not exist, the system should handle this event and create new files.

Coding and Design

You can use the following class descriptions as a guideline for your design.

(At minimum two java files should be used)

Student: This class should implement serializable (Refer to figure 1).

LogEntry: This class should implement serializable and comparable interface to use an inbuilt java Collections.sort() method. (Refer to figure 1).

Example) SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy-HH:mm:ss");

WriteToFile: This class persist all the contents from the data structures to the text files.

TCPClient: This class handles the data entry with suitable menus and interacts with the user. This program creates an instance of (Student /LogEntry / String) on user selection before sending it to the server. Socket,

ObjectInputStream and ObjectOutputStreamfor for TCP Connection should be used. The program should allow the client to enter the details for multiple entries.

TCPServer: This server loads existing records from the text files (“studententry.txt” and “logentries.txt”) to appropriate data structures preferably an ArrayList. A timer function should be used to regularly schedule the contents of the ArrayList to be written to the two text files every 3 minutes. The “logentries.txt” should contain entries sorted by the student number. The server program should be running indefinitely ready to communicate with all future clients.

Figure 1(Design)

Your program should check user inputs for potential error and allow user to re-enter details where appropriate. The source code should be formatted properly following good programming practice (appropriate variable names, indentation, comments, etc.…)

 studententry.txt 

 Logentry.txt 

Client 1

Client 2

Output of TCP Sever

Sample Screenshots

The following screenshots show example outputs of the above program. You should only use these as references. Your program outputs can be similar but not necessarily the same.

Structure of studententry.txt and logentry.txt(two fields space separated) with Client/Server program interaction.

Output of TCPServer:

Report

Include an end user instruction and test manual. Run the program and take screenshot of program outputs for all tests with annotations. The test should demonstrate that your TCPServer can accept connections from more than one TCPClient. Provide screenshots of your “studententry.txt” and “logentry.txt”.

Note:

1. If your program doesn’t compile or run, partial marks will be allocated by inspection of the source code.
2. Your understanding of the program will be examined using your report and the detailed java doc comments inserted in your source code files.
3. Please clarify any doubts you have by one of the means of discussing with your tutor, posting a query in the Q& A forum, or discussing with your colleagues or contacting the unit coordinator.
4. Please do not share your source code files or report with your colleagues which may lead to plagiarism.