Connect Four

A simple version of the popular game "connect four" written in Java.

API docs

SOCKET API

Basic structure

The structure of the API is really simple. Commands consist of words separated by spaces. The first word is always the command, the following ones are the parameters. The commands are delivered via plain tcp sockets.

Data Types:

• boolean:
  • 'true'
  • 'false'
• int: Number
• PlateType:
  • 'X' (red)
  • 'O' (black)
• GameOverReason:
  • 'Winner' -> somebody won
  • 'Draw' -> the board is full
  • 'OpponentDisconnected' -> the opponent disconnected
  • 'Error' -> some error with the scket connection

Commands

• setUsingPlateType
  • direction:
    • Server -> Client
  • usage:
    • This is the first command the server sends to the client after a connection is established.
    • The client shall use this plate type for his player.
  • parameters: 1: (PlateType) for the client to use
• setIsMyTurn
  • direction:
    • Server -> Client
  • usage:
    • Sent to indicate which player's turn it currently is.
    • It is sent for every player after every move.
  • parameters:
    • 1: (PlateType) of the targeted player
    • 2: (boolean) If it is this player's turn
• doMove:
  • direction:
    • Client -> Server
  • usage:
    • Sent in order to perform a move.
    • The server will respond with the command movePerformed or invalidMove
  • parameters:
    • 1: (int) Number of the column to insert the plate into
• movePerformed
  • direction:
    • Server -> Client
  • usage:
    • Sent when a player (client- or serverside) has performed a move.
    • If the move was performed by the client, the command will be sent nevertheless.
  • parameters:
    • 1: (PlateType) of the player who performed the move.
    • 2: (int) Number of the column the plate was inserted into.
• invalidMove
  • direction:
    • Server -> Client
  • usage:
    • Sent the client has tried to perform an invalid move (eg. when it was not his turn)
  • parameters:
    • 1: (int) the column the client tried to insert into
• gameOver
  • direcion:
    • Server -> Client
  • usage:
    • Sent when the game is over
  • parameters:
    • 1: (GameOverReason) Reason for the end of the game.
    • 2: (PlateType) if parameter 1 is 'Winner' otherwise nothing
• gameReset
  • direction:
    • Server <-> Client
  • usage:
    • Sent to indicate that the socket connection will be closed.
    • Just closing shall have the same effect.
    • If the game is not over yet, it shall be ended with the reason 'OpponentDisconnected'
  • parameters:
    • none

Example

The communiction between a server and a client could look like this:

Direction	Command	Meaning
Server -> Client	setUsingPlateType X	The client has to use the PlateTye X
Server -> Client	setIsMyTurn O true	It is the server's turn
Server -> Client	setIsMyTurn X false
Server -> Client	movePerformed O 6	The server inserted a Plate into column 6
Server -> Client	setIsMyTurn O false
Server -> Client	setIsMyTurn X true	It is the client's turn
Client -> Server	doMove 0	The client wants to insert a Plate into colum 0
Server -> Client	movePerformed X 0	The move of the client was accepted and the move was performed
Server -> Client	setIsMyTurn X false
Server -> Client	setIsMyTurn O true	It is the server's turn
Server -> Client	movePerformed O 6	The server inserted a Plate into column 6
Server -> Client	setIsMyTurn O false
Server -> Client	setIsMyTurn X true
Client -> Server	doMove 0
Server -> Client	movePerformed X 0
Server -> Client	setIsMyTurn X false
Server -> Client	setIsMyTurn O true
Server -> Client	movePerformed O 6
Server -> Client	setIsMyTurn O false
Server -> Client	setIsMyTurn X true
Client -> Server	doMove 0
Server -> Client	movePerformed X 0
Server -> Client	setIsMyTurn X false
Server -> Client	setIsMyTurn O true
Server -> Client	movePerformed O 6
Server -> Client	gameOver Winner O	The game is over, the server won
Server -> Client	gameReset	The server performed a reset

This example ends with a board that looks like this:

---------
|       |
|       |
|      O|
|X     O|
|X     O|
|X     O|
---------