Objective

This project has several objectives.  Those objectives are:

• Learn to implement client-server networking applications.
• Learning how to use Java networking classes.
• Stream manipulation for both file & network I/O.
• Learn to use Java threads & synchronization.
• Practice using the Java API.

This project is considered a closed project.  Make sure you read the open/closed policy before continuing working on this project.

Project Clarifications

Any clarifications or corrections associated with this project will be available at:

http://www.cs.umd.edu/class/fall2007/cmsc132/projects/p8/clarifications.html

Overview

For this project you will complete the following tasks:

• Implement classes to support online voting for a Terp Idol contest using a client-server programming model. 
• Implement stream & string processing methods to read and process text files and web pages.
• Implement multithreading to support running multiple contest clients and the contest server concurrently.

Javadoc documentation for this project can be found at CMSC 132 Terp Idol.

Your project will be graded as follows:

Public JUnit tests                                      45 %

Release JUnit tests                                  50 %

Style                                                            5 %

For this project:

• No secret testing is associated with this project. 

• The project's code distribution is available by checking out the project named p8. The code distribution provides you with the following:
  • A folder named src - In this folder you will find the packages genClientServer, terpIdol, terpIdolGUIs and tests.
  • A package named genClientServer - In this package you will implement generic client/server classes.
  • A package named terpIdol - In this package you will implement the terpIdol client & server.
  • A package named tests - You will find the JUnit public tests we provided in this package.
  • A folder named web -   Provides some documents used by your public tests.
  • A file named information.txt - This file is used by the terpIdol server.

Specifications

Terp Idol Rules

The Terp Idol contest is run in a similar manner as American Idol.

• The contest consists of a number of rounds.
• Each round begins with a number of contestants.
• Voters vote for individual contestants (as many times as they wish).
• At the end of a round, the contestant with the fewest votes is eliminated.
• In case of ties, the contestant whose name is alphabetically first is eliminated.
• Votes for remaining contestants are reset to 0 at the beginning of a new round.
• Last remaining contestant is the winner.

Client-Server Programming Model

Your code must use a client-server programming model, where clients initiate contact with the server to request some service.  The server waits for incoming client requests and sends back the appropriate response. Your task is to implement client and server classes that we can use to run online voting & information gathering for a Terp Idol contest. To do so you must implement code in the classes Client, Server, ContestServer, IdolCommandProcessor, and IdolClient classes. The strings representing the messages between clients and the server are defined as static final in the Const class, and may be used in other classes using "import static terpIdol.Consts.*;".

You will first implement two classes (Client, Server) that provide the basic client/server functionality.  For the server, this functionality will be:

• Server - After accepting a client connection request the server must create a thread that handles any future client requests so that the server can keep accepting new clients even if previous clients have not disconnected. If a client request is different from a disconnect or ping request then the request will be handled by the command processor. The server will not run as a deamon thread (classes extending the server will decide that).  Client requests and server responses are strings of data.
• Client - This class represents a generic client for a client/server application.  It provides the following functionality: connecting/disconnecting  to/from the server, sending/receiving strings of data, and executing a ping command.

You will use the Server and Client classes to implement a particular client and server terpIdol application.  The classes you must implement are:

• IdolCommandProcessor - This class implements the server processing associated with terpIdol client requests.
• ContestServer - This class extends the Server class and starts the server in a separate (daemon) thread. In addition it utilizes the IdolCommandProcessor class to provide the expected terpIdol server functionality.
• IdolClient - This class extends the Client class and defines the requests the server will receive.

Client-Server Requests

The list of requests the terpIdol contest server must process are shown in the following table:

• LOOKUP - The server keeps track of information about individuals in a file called information.txt (one name per line). When a client submits a LOOKUP request, the server will look up the specified individual and return LOOKUP plus the line in the file.  If no line begins with the name, then REQUEST_FAILED is returned.

• IMAGE - An image search request is specified by the client by sending a URL for the target. The server must return the URLs of all images found on the target.

To recognize images, the server will search through the html code of the specified web page, looking for entries starting with "<img src="  where any number of spaces and options (e.g. border) may exist in between img and src.   An image is represented by the string following "src=", ending in a quotation mark. For instance, the following text are examples of possible image URLs for which you will be searching.

Additional Information

• You can use the java.util.Date class to generate the date (e.g., System.out.println(new Date());).
• You can invite contestants that are not present in the information.txt file.
• The server will return REQUEST FAILED if a person is not found during a look up operation.
• The server will return REQUEST FAILED if a new round is started without any contestants.
• If there is vote for a contestant that is not part of the current round, then the server will return REQUEST FAILED followed by the contestant's name.
• If there is an invite request for a contestant already invited, then the server will return REQUEST FAILED followed by the name of the contestant.
• Your multithreaded code must use synchronization to avoid data races.

Java Language Requirements

• You must use Java socket classes for the networking functionality.
• Client/Server communication should use the DataOutputStream writeUTF method (sending data) and DataInputStream readUTF method (receiving data).

Style Requirements

• You must avoid code duplication.  For example, if several methods in your class share the same code fragment place that fragment in a private method.
• You must follow Java conventions for identifiers.  For example, class/interface names must start with capitals.
• You must use meaningful variable names.
• You must indent your code using three or four spaces or by using the Eclipse "Correct Indentation" option.
• You must use the same style for blocks of curly brackets ({ }) throughout your code. 

Video

The video TerpIdolVideo.avi illustrate some of the functionality associated with the system you are expected to implement.

Submission

Submit your project using the submit project option associated with Eclipse. 

Academic Integrity

Please make sure you read the academic integrity section of the syllabus so you understand what is permissible in our programming projects.  We want to remind you that we check your project against other students' projects and any case of academic dishonesty will be referred to the University's Office of Judicial Program