HW#5 --- last modified January 16 2019 00:35:19..

Solution set.

Due date:  June 6
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Files to be submitted: p20bhw5file1.zip
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HW5 Purpose:  To gain familiarity with network sockets and UDP and TCP
============  transmission.

Specification:
==============
For this homework you will make client and server programs to play
Pong over the internet. Note: to play the game on one computer
you might have to keep clicking back and forth between two windows
then hitting the direction key you want. In the PIC lab you can always
log into two machines and play between them.
Recall Pong is the 1972 video ping-pong game from Atari (although see
http://www.emuunlim.com/doteaters/play1sta1.htm for a 1958-9 version of
pong played on a modified oscillascope). You can see a screen shot
of Pong here http://www.emuunlim.com/doteaters/play1sta2.htm .
Like the Tic-tac-toe game in the book the server should have two player
threads to handle the communication with each player. Initially, while
waiting for two players the client uses stream sockets. It assigns
the first player that connects to the paddle on the left hand side of the
screen. This player uses the keys 1 and 2 for up and down. The second
player to connect gets the right hand paddle and uses keys 9 and 0 to move.
After both players have connected it sends a message to both players that a
round (for this discussion, a round will mean a competition for a point)
is to begin. The client programs should use a JTextfield and a JButton
called Connect to get the URL of the server to connect to. They should
also have a screen showing the current picture of the game.
During a round the server uses a timer to send datagrams to
each player every 100ms. This datagram consists of three pieces of information:
(1) the x,y position of the ball on the screen (4 bytes), (2) the y position
of the first player (2 bytes) and (3) the y
position of the second player (2 bytes). Meanwhile each client uses a
KeyListener to listen for the keys corresponding to its paddle. When
one of these keys is pressed it sends over its stream socket with its
corresponding server player thread one byte 0 for down 255 for up.
The server's player thread then updates the position of the player
according to the move it receives. When the ball goes out of bounds,
the server sends using its stream sockets that the round is over, followed
by the current score. If no person has scored 10 yet then after a 3 second
delay a new round signal byte is sent by the server. Otherwise, a game over
disconnect signal is sent and the connections are closed. If the
clients each click on Connect they can start a new game.


Point Breakdown for HW5
=======================
Documentation..........................1pt
Client application has a JTextfield
  and button which work as described...1pt
Client windows displays current
  paddles and and ball correctly.......1pt
Server uses timer to send datagrams....1pt
Server has two player threads
 which works as described..............1pt
Client key presses send stream socket
 data as described above to Server.....1pt
Server updates player position
 according to keypresses received......1pt
Server correctly ends round when ball
 goes out of bounds....................1pt
There is a three second minimum delay
 between rounds........................1pt
Server correctly end games when someone
 gets 10 points........................1pt

Total.................................10pts