org.dhcp4java

Class DHCPCoreServer

java.lang.Object

org.dhcp4java.DHCPCoreServer

All Implemented Interfaces:

Runnable

public class DHCPCoreServer
extends Object
implements Runnable

A simple generic DHCP Server. The DHCP Server provided is based on a multi-thread model. The main thread listens at the socket, then dispatches work to a pool of threads running the servlet.

Configuration: the Server reads the following properties in "/DHCPd.properties" at the root of the class path. You can however provide a properties set when contructing the server. Default values are:

serverAddress=127.0.0.1:67 [address:port]
serverThreads=2 [number of concurrent threads for servlets]

Note: this class implements Runnable allowing it to be run in a dedicated thread.

Example:

 public static void main (String [] args)
 {
   try
   {
     DHCPCoreServer server = DHCPCoreServer.initServer (new DHCPStaticServlet (), null);
     new Thread (server).start ();
   }
   catch (DHCPServerInitException e)
   {
     // die gracefully
   }
 }
 

Version:

1.00

Author:

Stephan Hadinger

Field Summary

Fields

Modifier and Type	Field and Description
protected Properties	m_aProperties Consolidated parameters of the server.
protected DHCPServlet	m_aServlet the servlet it must run
protected ThreadPoolExecutor	m_aThreadPool working threads pool.
protected Properties	m_aUserProps Reference of user-provided parameters
protected static int	PACKET_SIZE default MTU for ethernet
static String	SERVER_ADDRESS
static String	SERVER_THREADS
static String	SERVER_THREADS_KEEPALIVE
static String	SERVER_THREADS_MAX

Method Summary

Modifier and Type	Method and Description
protected void	dispatch()
protected InetSocketAddress	getInetSocketAddress(Properties props) Returns the InetSocketAddress for the server (client-side).
InetSocketAddress	getSockAddress()
protected void	init() Initialize the server context from the Properties, and open socket.
static DHCPCoreServer	initServer(DHCPServlet servlet, Properties userProps) Creates and initializes a new DHCP Server.
static InetSocketAddress	parseSocketAddress(String address) Parse a string of the form 'server:port' or '192.168.1.10:67'.
void	run() This is the main loop for accepting new request and delegating work to servlets in different threads.
protected void	sendResponse(DatagramPacket responseDatagram) Send back response packet to client.
void	stopServer() This method stops the server and closes the socket.

Methods inherited from class java.lang.Object

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

Field Detail

PACKET_SIZE

protected static final int PACKET_SIZE

default MTU for ethernet

See Also:

Constant Field Values

m_aServlet

protected DHCPServlet m_aServlet

the servlet it must run

m_aThreadPool

protected ThreadPoolExecutor m_aThreadPool

working threads pool.

m_aProperties

protected Properties m_aProperties

Consolidated parameters of the server.

m_aUserProps

protected Properties m_aUserProps

Reference of user-provided parameters

SERVER_ADDRESS

public static final String SERVER_ADDRESS

See Also:

Constant Field Values

SERVER_THREADS

public static final String SERVER_THREADS

See Also:

Constant Field Values

SERVER_THREADS_MAX

public static final String SERVER_THREADS_MAX

See Also:

Constant Field Values

SERVER_THREADS_KEEPALIVE

public static final String SERVER_THREADS_KEEPALIVE

See Also:

Constant Field Values

Method Detail

initServer

public static DHCPCoreServer initServer(DHCPServlet servlet,
                                        Properties userProps)
                                 throws DHCPServerInitException

Creates and initializes a new DHCP Server.

It instanciates the object, then calls init() method.

Parameters:

servlet - the DHCPServlet instance processing incoming requests, must not be null.

userProps - specific properties, overriding file and default properties, may be null.

Returns:

the new DHCPCoreServer instance (never null).

Throws:

DHCPServerInitException - unable to start the server.

init

protected void init()
             throws DHCPServerInitException

Initialize the server context from the Properties, and open socket.

Throws:

DHCPServerInitException - on error

dispatch

protected void dispatch()

sendResponse

protected void sendResponse(DatagramPacket responseDatagram)

Send back response packet to client.

This is a callback method used by servlet dispatchers to send back responses.

Parameters:

responseDatagram - suff to send back

getInetSocketAddress

protected InetSocketAddress getInetSocketAddress(Properties props)

Returns the InetSocketAddress for the server (client-side).

  serverAddress (default 127.0.0.1)
  serverPort (default 67)
 

This method can be overridden to specify an non default socket behaviour

Parameters:

props - Properties loaded from /DHCPd.properties

Returns:

the socket address, null if there was a problem

parseSocketAddress

public static InetSocketAddress parseSocketAddress(String address)

Parse a string of the form 'server:port' or '192.168.1.10:67'.

Parameters:

address - string to parse

Returns:

InetSocketAddress newly created

Throws:

IllegalArgumentException - if unable to parse string

run

public void run()

This is the main loop for accepting new request and delegating work to servlets in different threads.

Specified by:

run in interface Runnable

stopServer

public void stopServer()

This method stops the server and closes the socket.

getSockAddress

public InetSocketAddress getSockAddress()

Returns:

Returns the socket address.