com.ccg.net.tcp
Class Server

java.lang.Object
  com.ccg.net.tcp.Server

public abstract class Server
extends Object

Fundamental building block for TCP servers.

This class implements the fundamental building blocks for creating a TCP service. It does most of the setup work required for creating a TCP server. You use this class in the following manner:

• You extend the class and implement the newConnection(java.net.Socket) method to handle incoming client connections. Your implementation should not block (you will most likely need to spawn off threads).
• You set the port number to listen for incoming connection and any other properties for the object (the setProperties(com.ccg.util.TagLookup) method is handy for this).
• You then start the server - it will call your implementation of newConnection(java.net.Socket) each time a client connects to your server.

The best way to see how to use this class is to look at the example program TimeServer.java which implements a simple server that sends the client information about the server's time and the client's connection.

Since:

1.0

Version:

$Revision: 1.3 $

Author:

$Author: pkb $

See Also:

TimeServer.java

Field Summary

(package private) int

_AcceptCount Holds how many connections have been accepted.

Constructor Summary

Server()
Initializes object to its default state.

Method Summary

int	getAcceptCount() Get how many connections have been accepted.
int	getPort() Get the TCP port number to listen for connections
SocketOptions	getSocketOptions() Get the socket options to apply to all incoming connections
boolean	isShutdown() Is server shutdown set?
protected abstract void	newConnection(Socket s) What to do with each incoming connection.
void	setPort(int val) Set the TCP port number to listen for connections
Exception	setProperties(TagLookup tl) Set the value of the object from values specified in a TagLookup table.
void	setSocketOptions(SocketOptions val) Set the socket options to apply to all incoming connections This method allows one to specify a specific set of socket options (receive buffer size, send buffer size, etc), which should be applied to all incoming connections.
void	start() Starts the Server.
void	stop() Attempt to gracefully shutdown the server.
String	toString() Get the name/tag of the server.

Methods inherited from class java.lang.Object

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

Field Detail

_AcceptCount

int _AcceptCount

Holds how many connections have been accepted.

Since:

1.0

Constructor Detail

Server

public Server()

Initializes object to its default state.

After initializing a object using this method, one will want to set the TCP port number to listen for incoming connections and then start the server up as a background thread. Once this is done, the start() method will take care of accepting incoming TCP connections and dispatch them to the newConnection(java.net.Socket) method which derived classes will use to provide their clients with a service.

Since:

1.0

See Also:

setPort(int), start()

Method Detail

newConnection

protected abstract void newConnection(Socket s)

What to do with each incoming connection. This method is invoked every time the server accepts an incoming connection. This method must be implemented by derived classes. It's up to the derived class as to what to do with the client's which connect (you should close the socket when you are done with it).

The server will not accept anymore connections (clients) until this method returns. In almost all cases, implementations of this method will spawn off at least one separate thread to interact with the clients connection.

Parameters:

s - The Socket to use to communicate with the client.

Since:

1.0

See Also:

start()

setSocketOptions

public void setSocketOptions(SocketOptions val)

Set the socket options to apply to all incoming connections This method allows one to specify a specific set of socket options (receive buffer size, send buffer size, etc), which should be applied to all incoming connections. By default, this will be null indicating that no special options should be applied.

Parameters:

val - New SocketOptions value to assign (pass null to leave connections in the system default state).

See Also:

getSocketOptions()

getSocketOptions

public SocketOptions getSocketOptions()

Get the socket options to apply to all incoming connections

Returns:

Current SocketOptions value assigned.

See Also:

setSocketOptions(com.ccg.net.tcp.SocketOptions)

setPort

public void setPort(int val)

Set the TCP port number to listen for connections

Parameters:

val - New int value to assign.

See Also:

getPort()

getPort

public int getPort()

Get the TCP port number to listen for connections

Returns:

Current int value assigned.

See Also:

setPort(int)

stop

public void stop()

Attempt to gracefully shutdown the server. This method will attempt to gracefully shutdown the server. This means that the server should stop accepting connections. see #isShutdown

start

public void start()

Starts the Server. This method is used to start the Server. This will create a background thread which will start listening for connections on the specified port (the thread will "idle" if you haven't specified a port yet). Every incoming connection accepted will then trigger the invocation of newConnection(java.net.Socket). Use stop() when you are ready to shutdown the server.

Since:

1.0

See Also:

stop()

isShutdown

public boolean isShutdown()

Is server shutdown set?

Returns:

Current boolean value assigned. see #setShutdown

getAcceptCount

public int getAcceptCount()

Get how many connections have been accepted.

Returns:

Total number of connections this object has accepted.

See Also:

start()

toString

public String toString()

Get the name/tag of the server.

Overrides:

toString in class Object

Returns:

Name/tag to associate with the server, "tcp" by default - used for logging messages and setting the name of the background thread.

Since:

1.0

See Also:

start()

setProperties

public Exception setProperties(TagLookup tl)

Set the value of the object from values specified in a TagLookup table. This is a very flexible method to set the values contained in this object based upon the values retrieved from the passed TagLookup table (which can originate from about any source - command line, applet parameters, property files, etc). All values are optional - if not specified in the lookup table, this object won't update its current settings for the omitted fields. The following properties are recognized:

port=PORT

The TCP port to listen for incoming connections on.

SocketOptions

All of the options recognized by SocketOptions.setProperties(com.ccg.util.TagLookup) are also recognized (receive buffer size, transmit buffer size, etc.).

Parameters:

tl - The TagLookup table to fetch properties for.

Since:

1.0

See Also:

setPort(int), SocketOptions.setProperties(com.ccg.util.TagLookup)