File Sharing System Part 2

You are asked to add the following capabilities to the file sharing system developed in the previous programming assignment:

• Ability to discover files stored in other filer servers.
• Ability to download files stored in other file servers.

Your current implementation should allow a client to connect to a given file server and download/upload files. You need to extend that functionality to allow the file server to search other file servers when it does not have the file requested for download locally. The following example describes how your system should behave:

• Client A connects to file server B and requests to download file X
• If file server B has the file X locally, it services the request
• Otherwise, server B initiates a file discovery process as follows
• B broadcasts a discovery request for file X to all of the other file servers in the system
• Other file servers receive the request, search their local repository, and respond as to whether they have that file or not
• File server B receives the responses and sends them back to the client
• The client displays the possibilities to the user, who initiates the download from one of the remote servers that has the file

You may only use Java RMI for developing the additional new capabilities. However, the functionality to upload/download files from the server developed using Java sockets in programming assignment #1 could be reused. No other use of third party software is allowed, unless explicitly permitted by the instructor.

Your implementation should allow for creation of arbitrary number of servers and clients.

The implementation should allow for the TA to specify the address of the RMI registry servers. One effective approach is to allow the user to pass the RMI registry server address as a parameter when running the Jar file. Hardcoding it would not work, because the TA is likely to use a different IP/Port number for testing your system.