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ECE 3332 - Project 3 Fall 2002 Overview. In this project you will convert your Project 2 solution to a client-server network solution. The details are below. NOTE: This design in no way resembles the way a real auction client and server would be designed! This is a programming exercise, not a design exercise. 1. GUI. In general, the GUI for this project can be the same as that for Project 2, unless I have indicated shortcomings in your GUI when I graded Project 2. The GUI front-end portion of Project 2 was supposed to communicate with your UHBay object. The same will be true for this project (except as described below), so the GUI need not change unless you need to make corrections and/or improvements. 2. When your Main object looks for an image file, it must look for it in two places: First, look for it in the current working directory (which will be your project directory when the program is run). If it is not found there, then look for it in \\laser\dropfolders\Ece3332pool\classes . 3. You will split up the functions of your current UHBay class between two new classes, UHBayClient and Server (both in the auction package). a. UHBayClient. This class will provide the client side of the auction. The client is the portion of the auction that runs on the user machine. s ? The API for this class can be the same as your current UHBay class, but the client ? does not actually contain the inventory of the auction; the auction server will do that. ? The client communicates with the auction server over the network. When the client ? is asked by the GUI to sell an item, provide a list of items, or perform any other operation, it will forward that request to the auction server for execution. In other words, to the GUI, the new UHBayClient looks like the old UHBay; but the UHBayClient is actually just a communications conduit to the Server using the Network Auction Protocol (NAP). ? The NAP is designed such that your current AuctionItem and Auctionable ? objects can write and read themselves the same way they do in Project 2; but this time the PrintWriter to which they write, and the BufferedReader from which they read, will be connected to a network stream. ? Your new UHBayClient class will have no use for UHBay ? s saveInventory() and loadInventory() methods, so you may remove them and also remove that capability from the GUI. However, you should retain the clear inventory capability, as we will want to use that for the purpose of testing the server. ? On the GUI, add a JComboBox that allows the user to select Remote or Local ? for the auction server. Also add a Connect but that initiates the connection to the server on port 3332. If Local is selected, connect to 127.0.0.1, the machine you are running on. If Remote is selected, connect to my office computer, 129.7.206.72. Of course, the server, listening on port 3332, must be started up before any client attempts a connection. Also add a Disconnect button that closes the connection to the server. b. Server. The auction server is that portion of the auction that runs on the remote computer. It receives commands over the network from the auction client and responds back to the client over the network.
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? The auction server maintains the inventory of auction items in much the same way ? as the UHBay did in Project 2. However, there is one main difference: the server does not actually store instances of AuctionItem, but instead simply stores the strings representing the items received from the client via the NAP. To repeat, the server does not ever actually deal with the AuctionItem class, just strings. ? For each item it is asked to sell, the server (not UHBayClient) will assign an item ? number and store the item number along with all of the other strings representing that item. ? The auction server must be designed as a multithreaded server so that it can handle ? multiple simultaneous auction clients. It listens on port 3332 and passes connections off to separate handler threads. Keep in mind that the server has inventory one shared by all clients that may connect to it. ? The server can be stopped only by entering ctl-C. The server must catch all ? exceptions and simply print error messages to the screen, but never exit. 4. Network Auction Protocol. You must use the Network Auction Protocol (NAP). Using NAP, the auction client will open a connection to the auction server to communicate the user requests: sell an item, list all items, list a particular item, clear all items. The protocol s will be session-oriented, such that the client maintains the open connection to the server until the client disconnects using the bye command. You must implement NAP faithfully so that any client can communicate with any server in our class. 5. Design Points. ? Be sure to synchronize those methods on the server that need to be synchronized in the ? multithreaded environment. Do not synchronize methods that do not need to be. Analyze the situation! ? You should set a timeout on the sockets (see API docs) on both client and server at ? appropriate times so that your client or server does not get hung when communicating with a faulty server or client. 6. Project 2 Corrections. Be certain to implement all corrections/suggestions described in the grading comments provided to you on Project 2. Suggestions not implemented will count off this time; corrections not made will count double this time. 7. Network Connection. During your development, you will probably not be able to place the auction server on a remote machine, so the server will have to be on the same machine as the client. Therefore, simply use 127.0.0.1 as the IP address of the server, and connect to port 3332. Your server, listening on port 3332, will have to be started up before any client attempts a connection. 8. Testing. You can test the multithreaded capability of your server by connecting two of your clients to it at the same time. I will certainly have fun doing that! 9. Style. Use Java Code Conventions style for your coding, with comments for every class, method, instance variable, and important sections/lines of code. See the link on the course home page. 10. Documentation. Use full Javadoc comments for the public and protected methods in ALL classes in the auction package. Create a docs subdirectory in your auction directory. In the auction directory, run Javadoc to create the corresponding html documents: javadoc d docs *.java
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