===== Exercises =====

** Exercise 1. **

Create a simplified FTP (file transport) client and **blocking** server where the client can send or download text files from the server:

== General use-cases ==
  -) Client connects to the server and sends a 'file listing' message
  -) Server sends back the list of the downloadable files
  -) Client lists the files and asks the user what action they want to take? Upload or download? ('u' or 'd') 
  -) In both cases users must give the full file name with extension
  -) The client sends the selected file to the server (upload) or downloads the selected file from the server to a specific directory.


== Server viewpoint ==
  -) After connecting, it reads the files from the /store subdirectory and sends the file names to the client after receiving the listing message. 
  -) We are waiting for the client's 'u' or 'd' operation 
  -) We get a filename from the client and if the action is 'd' (download), we read the file content and return its contents
  -) If the operation is 'u' (upload), we open a new file with the specified name and wait for the data to be written to the file.

== Client viewpoint ==

  -) The client connects and waits for the list of files coming back and writes it to the console 
  -) We ask for the "u" or "d" key 
  -) Then we'll ask for the file-name as well. 
  -) The client reads the files from the /files folder, or creates the downloaded file here
  -) If you press "d", it creates /files/ and writes data from the server
  -) If you press "u", /files/ is sent to the server


** Exercise 2. **
Modify the **blocking** UDP code so that you can transfer a 'wired-in' name and existing binary image file larger than 2 kbytes and verify that it was successfully sent, eg. try to open the sent image by hand, in the Paint app.

** Exercise 3. **
Try out the non-blocking starter Java code and examine/debug it.