/*
* Copyright (c) 2000, 2001, 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 java.nio.channels;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.SocketAddress;
import java.nio.channels.spi.*;
/**
* A selectable channel for stream-oriented listening sockets.
*
* <p> Server-socket channels are not a complete abstraction of listening
* network sockets. Binding and the manipulation of socket options must be
* done through an associated {@link java.net.ServerSocket} object obtained by
* invoking the {@link #socket() socket} method. It is not possible to create
* a channel for an arbitrary, pre-existing server socket, nor is it possible
* to specify the {@link java.net.SocketImpl} object to be used by a server
* socket associated with a server-socket channel.
*
* <p> A server-socket channel is created by invoking the {@link #open() open}
* method of this class. A newly-created server-socket channel is open but not
* yet bound. An attempt to invoke the {@link #accept() accept} method of an
* unbound server-socket channel will cause a {@link NotYetBoundException} to
* be thrown. A server-socket channel can be bound by invoking one of the
* {@link java.net.ServerSocket#bind(java.net.SocketAddress,int) bind} methods
* of an associated server socket.
*
* <p> Server-socket channels are safe for use by multiple concurrent threads.
* </p>
*
*
* @author Mark Reinhold
* @author JSR-51 Expert Group
* @since 1.4
*/
public abstract class ServerSocketChannel
extends AbstractSelectableChannel
{
/**
* Initializes a new instance of this class.
*/
protected ServerSocketChannel(SelectorProvider provider) {
super(provider);
}
/**
* Opens a server-socket channel.
*
* <p> The new channel is created by invoking the {@link
* java.nio.channels.spi.SelectorProvider#openServerSocketChannel
* openServerSocketChannel} method of the system-wide default {@link
* java.nio.channels.spi.SelectorProvider} object.
*
* <p> The new channel's socket is initially unbound; it must be bound to a
* specific address via one of its socket's {@link
* java.net.ServerSocket#bind(SocketAddress) bind} methods before
* connections can be accepted. </p>
*
* @return A new socket channel
*
* @throws IOException
* If an I/O error occurs
*/
public static ServerSocketChannel open() throws IOException {
return SelectorProvider.provider().openServerSocketChannel();
}
/**
* Returns an operation set identifying this channel's supported
* operations.
*
* <p> Server-socket channels only support the accepting of new
* connections, so this method returns {@link SelectionKey#OP_ACCEPT}.
* </p>
*
* @return The valid-operation set
*/
public final int validOps() {
return SelectionKey.OP_ACCEPT;
}
// -- ServerSocket-specific operations --
/**
* Retrieves a server socket associated with this channel.
*
* <p> The returned object will not declare any public methods that are not
* declared in the {@link java.net.ServerSocket} class. </p>
*
* @return A server socket associated with this channel
*/
public abstract ServerSocket socket();
/**
* Accepts a connection made to this channel's socket.
*
* <p> If this channel is in non-blocking mode then this method will
* immediately return <tt>null</tt> if there are no pending connections.
* Otherwise it will block indefinitely until a new connection is available
* or an I/O error occurs.
*
* <p> The socket channel returned by this method, if any, will be in
* blocking mode regardless of the blocking mode of this channel.
*
* <p> This method performs exactly the same security checks as the {@link
* java.net.ServerSocket#accept accept} method of the {@link
* java.net.ServerSocket} class. That is, if a security manager has been
* installed then for each new connection this method verifies that the
* address and port number of the connection's remote endpoint are
* permitted by the security manager's {@link
* java.lang.SecurityManager#checkAccept checkAccept} method. </p>
*
* @return The socket channel for the new connection,
* or <tt>null</tt> if this channel is in non-blocking mode
* and no connection is available to be accepted
*
* @throws ClosedChannelException
* If this channel is closed
*
* @throws AsynchronousCloseException
* If another thread closes this channel
* while the accept operation is in progress
*
* @throws ClosedByInterruptException
* If another thread interrupts the current thread
* while the accept operation is in progress, thereby
* closing the channel and setting the current thread's
* interrupt status
*
* @throws NotYetBoundException
* If this channel's socket has not yet been bound
*
* @throws SecurityException
* If a security manager has been installed
* and it does not permit access to the remote endpoint
* of the new connection
*
* @throws IOException
* If some other I/O error occurs
*/
public abstract SocketChannel accept() throws IOException;
}