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	/*
	* Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.net;

	import java.io.IOException;
	import java.net.InetAddress;
	import java.net.ServerSocket;
	import java.net.SocketException;

	/**
	* This class creates server sockets. It may be subclassed by other
	* factories, which create particular types of server sockets. This
	* provides a general framework for the addition of public socket-level
	* functionality. It is the server side analogue of a socket factory,
	* and similarly provides a way to capture a variety of policies related
	* to the sockets being constructed.
	*
	* <P> Like socket factories, server Socket factory instances have
	* methods used to create sockets. There is also an environment
	* specific default server socket factory; frameworks will often use
	* their own customized factory.
	*
	* @since 1.4
	* @see SocketFactory
	*
	* @author David Brownell
	*/
	public abstract class ServerSocketFactory
	{
	//
	// NOTE: JDK 1.1 bug in class GC, this can get collected
	// even though it's always accessible via getDefault().
	//
	private static ServerSocketFactory theFactory;


	/**
	* Creates a server socket factory.
	*/
	protected ServerSocketFactory() { /* NOTHING */ }

	/**
	* Returns a copy of the environment's default socket factory.
	*
	* @return the <code>ServerSocketFactory</code>
	*/
	public static ServerSocketFactory getDefault()
	{
	synchronized (ServerSocketFactory.class) {
	if (theFactory == null) {
	//
	// Different implementations of this method could
	// work rather differently. For example, driving
	// this from a system property, or using a different
	// implementation than JavaSoft's.
	//
	theFactory = new DefaultServerSocketFactory();
	}
	}

	return theFactory;
	}


	/**
	* Returns an unbound server socket. The socket is configured with
	* the socket options (such as accept timeout) given to this factory.
	*
	* @return the unbound socket
	* @throws IOException if the socket cannot be created
	* @see java.net.ServerSocket#bind(java.net.SocketAddress)
	* @see java.net.ServerSocket#bind(java.net.SocketAddress, int)
	* @see java.net.ServerSocket#ServerSocket()
	*/
	public ServerSocket createServerSocket() throws IOException {
	throw new SocketException("Unbound server sockets not implemented");
	}

	/**
	* Returns a server socket bound to the specified port.
	* The socket is configured with the socket options
	* (such as accept timeout) given to this factory.
	* <P>
	* If there is a security manager, its <code>checkListen</code>
	* method is called with the <code>port</code> argument as its
	* argument to ensure the operation is allowed. This could result
	* in a SecurityException.
	*
	* @param port the port to listen to
	* @return the <code>ServerSocket</code>
	* @throws IOException for networking errors
	* @throws SecurityException if a security manager exists and its
	* <code>checkListen</code> method doesn't allow the operation.
	* @throws IllegalArgumentException if the port parameter is outside the
	* specified range of valid port values, which is between 0 and
	* 65535, inclusive.
	* @see SecurityManager#checkListen
	* @see java.net.ServerSocket#ServerSocket(int)
	*/
	public abstract ServerSocket createServerSocket(int port)
	throws IOException;


	/**
	* Returns a server socket bound to the specified port, and uses the
	* specified connection backlog. The socket is configured with
	* the socket options (such as accept timeout) given to this factory.
	* <P>
	* The <code>backlog</code> argument must be a positive
	* value greater than 0. If the value passed if equal or less
	* than 0, then the default value will be assumed.
	* <P>
	* If there is a security manager, its <code>checkListen</code>
	* method is called with the <code>port</code> argument as its
	* argument to ensure the operation is allowed. This could result
	* in a SecurityException.
	*
	* @param port the port to listen to
	* @param backlog how many connections are queued
	* @return the <code>ServerSocket</code>
	* @throws IOException for networking errors
	* @throws SecurityException if a security manager exists and its
	* <code>checkListen</code> method doesn't allow the operation.
	* @throws IllegalArgumentException if the port parameter is outside the
	* specified range of valid port values, which is between 0 and
	* 65535, inclusive.
	* @see SecurityManager#checkListen
	* @see java.net.ServerSocket#ServerSocket(int, int)
	*/
	public abstract ServerSocket
	createServerSocket(int port, int backlog)
	throws IOException;


	/**
	* Returns a server socket bound to the specified port,
	* with a specified listen backlog and local IP.
	* <P>
	* The <code>ifAddress</code> argument can be used on a multi-homed
	* host for a <code>ServerSocket</code> that will only accept connect
	* requests to one of its addresses. If <code>ifAddress</code> is null,
	* it will accept connections on all local addresses. The socket is
	* configured with the socket options (such as accept timeout) given
	* to this factory.
	* <P>
	* The <code>backlog</code> argument must be a positive
	* value greater than 0. If the value passed if equal or less
	* than 0, then the default value will be assumed.
	* <P>
	* If there is a security manager, its <code>checkListen</code>
	* method is called with the <code>port</code> argument as its
	* argument to ensure the operation is allowed. This could result
	* in a SecurityException.
	*
	* @param port the port to listen to
	* @param backlog how many connections are queued
	* @param ifAddress the network interface address to use
	* @return the <code>ServerSocket</code>
	* @throws IOException for networking errors
	* @throws SecurityException if a security manager exists and its
	* <code>checkListen</code> method doesn't allow the operation.
	* @throws IllegalArgumentException if the port parameter is outside the
	* specified range of valid port values, which is between 0 and
	* 65535, inclusive.
	* @see SecurityManager#checkListen
	* @see java.net.ServerSocket#ServerSocket(int, int, java.net.InetAddress)
	*/
	public abstract ServerSocket
	createServerSocket(int port, int backlog, InetAddress ifAddress)
	throws IOException;
	}


	//
	// The default factory has NO intelligence. In fact it's not clear
	// what sort of intelligence servers need; the onus is on clients,
	// who have to know how to tunnel etc.
	//
	class DefaultServerSocketFactory extends ServerSocketFactory {

	DefaultServerSocketFactory()
	{
	/* NOTHING */
	}

	public ServerSocket createServerSocket()
	throws IOException
	{
	return new ServerSocket();
	}

	public ServerSocket createServerSocket(int port)
	throws IOException
	{
	return new ServerSocket(port);
	}

	public ServerSocket createServerSocket(int port, int backlog)
	throws IOException
	{
	return new ServerSocket(port, backlog);
	}

	public ServerSocket
	createServerSocket(int port, int backlog, InetAddress ifAddress)
	throws IOException
	{
	return new ServerSocket(port, backlog, ifAddress);
	}
	}

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