CS433/533 Programming Assignment 1: Socket API

This assignment gives you a chance to familiar with the basic Java socket programming interface, Java Thread, Java Asynchronous IO, and Java sleep or (java Timer).
Due: 11:59 PM, Feb. 18, Monday. Please see below for submission instruction.

Part 1. Performance Comparisons and Improvement of HTTP Servers

Please modify the programs below to implement HTTP server in three ways: sequential, multi-thread, and asynchronous i/o. The programs below are samples.

• seqHTTPServer.java

• mtHTTPServer.java

• asyncHTTPServer.java

For each approach, the command-line syntax should allow specification of at least port and www_root. You may want to add other switches to help with debugging and configuration.
% java <seqHTTPServer | mtHTTPServer | asyncHTTPServer> -port <port> -www_root <www_root>

We will use http_load (http://www.acme.com/software/http_load/) to test the performance of the servers. All related files are under /home/httpd/html/zoo/classes/cs433/assignments/prog1/

For this part of the assignment, you need to be able to do the following:

• Use /home/httpd/html/zoo/ as the www root
  
  
• Modify the three web servers so that a user can restrieve files under the www root. Although your web server may not be able to retrieve all files under the www root due to permission issues, it should be able to restrieve documents under /home/httpd/html/zoo/classes/cs433/assignments/prog1/www
  
  For example, if I am running my a web server on cicada at port 9876, and I want to restrieve  /home/httpd/html/zoo/classes/cs433/assignments/prog1/www/html-small/doc1.html
  I can type into my browser:
  http://cicada.cs.yale.edu:9876/classes/cs433/assignments/prog1/www/html-small/doc1.html
  
  If I type an URL that does not map into an invalid file name, please return Error and code 404.
  
  
• Test the performance of the servers using http_load. You may find this document helpful. We have installed http_load under /home/httpd/html/zoo/classes/cs433/assignments/prog1/http_load/
  An example url file is called urls.txt
  
  For the test, you will need to vary the parallel from 1 to 250 (or more until your server saturates) with a reasonable increment schedule (e.g., 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, ...). A reasonable test time is 60 to 120 seconds.
  
  Please conduct two test cases:
• All small html files. For this case, please use the 1000 files under /home/httpd/html/zoo/classes/cs433/assignments/prog1/www/html-small/
• A mix of small, big and jpg files: For this case, please use the first 500 files from html-small, the 100 files from html-big, and the 100 jpg files from jpg.
  
  
• Please report the measured performance for performance metrics: throughput and (mean) delay. The sample figure below may give you a sense of the testing results for throughput. Please add one optimization feature and validate the optimization. Thus, your results should contain at least four curves: one curve for each given server, and one for your optimization. You may want to conduct a test using the department server (http://zoo.cs.yale.edu) and compare the performance. Please discuss the lessons learned.

Part 2. A Concurrent Java TCP Relay Client with Timeout

• The function of this Java program is to relay between a user and a TCP server. It needs to provide the following functionalities:

  • any message from the keyboard is sent to the TCP server;

  • any message from the server is displayed to the user;

  • if the user is idle for <idle time> seconds, the program should close the socket and exit;

  • the Java program cannot block on either the keyboard input or the Socket input.
    

• You should implement both a thread version and an asynchronous i/o version.

• Command line: your program should  allow a user to specify server hostname, server port name, and the idle time before the program exits. It also can specify the implementation mode: asynchronous i/o or thread. the default should be thread.
  % java tcpRelay -h <hostname> -p <port number> -i <idle time in seconds> [-async | -thread]
   

• Submission
  • Please include a short description of your design along with your source code.

• References
  • Book
    • Java Network Programming, 3rd, 2005, by Elliotte Harold is a good reference book on Java network programming. In particular, you should read chapter 5 on Thread and chapter 12 on asynchronous i/o.
      • Yale library has electronic version of this book (you need Yale IP address to gain access). If this link does not work, please search the book title using Orbis, and follow the link.
      • The examples codes can be found here.
  • Tutorials
    • All About Sockets (Sun tutorial)
      • http://java.sun.com/docs/books/tutorial/networking/sockets/
    • Socket Programming in Java: a Tutorial
      • http://www.javaworld.com/javaworld/jw-12-1996/jw-12-sockets.html
    • Thread and timer
      • http://java.sun.com/docs/books/tutorial/essential/threads/
    • More details on Java IO (Java NIO)
      •  http://proquest.safaribooksonline.com/0596002882
      • http://www.cs.brown.edu/courses/cs161/papers/j-nio-ltr.pdf (IBM tutorial on NIO)
      • http://java.sun.com/j2se/1.4.2/docs/guide/nio/example/index.html (Sun async io examples)
        
  • General java information:
    • Development environments:
      • zoo has Java installed:
      • eclipse provides a nice java IDE.
    • Java book
      • An overall very good book on Java is is Thinking in Java (3rd Edition) by Bruce Eckel, Dec. 2002 (expected), by Prentice Hall. This book is also available online at web sites such as: http://www.bruceeckel.com/ or http://www.janiry.com/bruce-eckel/
• Suggestions
  • The objective of this assignment is to let you familiarize with the basic library. Please keep the program simple and there is no need to handle all exceptions too nicely. For example, if there is an exception when you close a socket but a thread is blocked on reading from the socket, just catch the exception.
  • Testing: make sure that your program can work with both an SMTP server and an HTTP server. For example:
    % java tcpRelay -h mr1.its.yale.edu -p 25 -i 1
    HELO <your address>
    MAIL FROM: <your address>
    RCPT TO: <destination address>
    DATA
    .
    Subject: This is subject
    From: <from address>
    To: <to address>
    
    Body
    .
    % java tcpRelay -h www.yale.edu -p 80 -i 1
    GET / HTTP/1.0
    
    ...

Submission

• Please submit using class server. Please generate a single jar file containing all of your files. The name of the jar file should be prog1.<netid>.jar. If you want to update, please rename it prog1A.<netid>.jar, etc.
  

Last Update: February 10, 2008 02:04:08 PM -0500