dd.net
Class NetServer

java.lang.Object
  dd.net.NetServer

All Implemented Interfaces:

java.lang.Runnable

public class NetServer

extends java.lang.Object

implements java.lang.Runnable

Base class for network server protocol. There are two classes responsible for the actual communication of messages from a game client to a game server. This is the implementation of the server part of that system. The communication is performed with TCP sockets that stay open for the duration of a game session. Unlike many request systems (like HTTP), both clients and servers can initiate requests. Therefore, both listen for commands from the other end and react accordingly.

The communication between client and server is predouminantly through a line-oriented text protocol. A command is usually a single line containing a command word and an arbitrary number of arguments. All the clients and servers do is interpret the network message and call the appropriate Handler that is registered to accept that kind of message.

The server keeps persistent references to each of the clients that are connected. Messages can be sent to specific clients or broadcast to all connected clients.

There is an implicit protocol implemented between the NetClient and NetServer. When either side sends the AYT message, the response should be the string [yes]. If an AYT response is not received, the client is assumed to be in an error state and disconnects. There is also a handshaking between client and server that goes as follows:

1. Client connects to server
2. Server sends a hello message in the form

       hello uniqueID
    

3. Client uses this unique ID to form a unique client ID name
4. Client sends a register message of the form

       register [uniqueID]
    

   (note the square brackets are part of the protocol, and are used to delemit the name of the client.

Alternatively, if the client is disconnected, register can be replaced with reconnect to inform the server that the client is replacing an existing client that terminated.

This class provides implementation of the behaviors described above as well as default debugging behaviors. To implement a custom client / server protocol, one can either subclass this class, or instantiate this class and provide it with Handler objects that perform the custom game protocol.

Author:

Eric Scharff

Field Summary

static int	DEFAULT_PORT Default TCP socket to use for client/server communication.
static java.lang.String	DISCOVERY_URL Well known URL to query for list of servers.
Logger	log Log object used for debugging messages.

Constructor Summary

NetServer()
Creates a new server listening on the default port.

NetServer(java.lang.String serverName)

NetServer(java.lang.String serverName, int port)

Method Summary

void	addClient(dd.net.NetServer.ServerClient client)
void	broadcast(java.lang.String message)
protected java.util.Iterator	getClientNames()
java.util.Set	getClients()
GameServer	getLobby()
void	handleReconnect(java.lang.String command, java.lang.String message, Client c)
void	handleRegister(java.lang.String command, java.lang.String message, Client c)
boolean	isReady()
boolean	isRunning()
static void	main(java.lang.String[] args)
boolean	registerVenue(java.lang.String venueName)
void	removeClient(Client client)
void	run()
void	sendTo(java.lang.String user, java.lang.String message)
void	setGame(GameServer g)
void	stopRunning()
void	unregisterVenue()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

log

public Logger log

Log object used for debugging messages.

DISCOVERY_URL

public static final java.lang.String DISCOVERY_URL

Well known URL to query for list of servers.

See Also:

Constant Field Values

DEFAULT_PORT

public static final int DEFAULT_PORT

Default TCP socket to use for client/server communication.

See Also:

Constant Field Values

Constructor Detail

NetServer

public NetServer()
          throws java.io.IOException

Creates a new server listening on the default port. The server will create a new server socket (if possible) and a thread to handle connections. The thread will start immediately.

NetServer

public NetServer(java.lang.String serverName)
          throws java.io.IOException

NetServer

public NetServer(java.lang.String serverName,
                 int port)
          throws java.io.IOException

Method Detail

registerVenue

public boolean registerVenue(java.lang.String venueName)
                      throws java.io.IOException

Throws:

java.io.IOException

unregisterVenue

public void unregisterVenue()

run

public void run()

Specified by:

run in interface java.lang.Runnable

addClient

public void addClient(dd.net.NetServer.ServerClient client)

setGame

public void setGame(GameServer g)

getLobby

public GameServer getLobby()

handleRegister

public void handleRegister(java.lang.String command,
                           java.lang.String message,
                           Client c)

handleReconnect

public void handleReconnect(java.lang.String command,
                            java.lang.String message,
                            Client c)

removeClient

public void removeClient(Client client)

getClientNames

protected java.util.Iterator getClientNames()

getClients

public java.util.Set getClients()

broadcast

public void broadcast(java.lang.String message)

sendTo

public void sendTo(java.lang.String user,
                   java.lang.String message)

isReady

public boolean isReady()

stopRunning

public void stopRunning()

isRunning

public boolean isRunning()

main

public static void main(java.lang.String[] args)