A server-socket channel is created by invoking the {@link #open() open} * method of this class. It is not possible to create a channel for an arbitrary, * pre-existing {@link ServerSocket}. 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 #bind(java.net.SocketAddress,int) bind} methods defined by this class. * *
Socket options are configured using the {@link #setOption(SocketOption,Object) * setOption} method. Server-socket channels support the following options: *
** Additional (implementation specific) options may also be supported. * **
** *Option Name *Description ** *{@link java.net.StandardSocketOptions#SO_RCVBUF SO_RCVBUF} *The size of the socket receive buffer ** *{@link java.net.StandardSocketOptions#SO_REUSEADDR SO_REUSEADDR} *Re-use address *
Server-socket channels are safe for use by multiple concurrent threads. *
* * @author Mark Reinhold * @author JSR-51 Expert Group * @since 1.4 */ public abstract class ServerSocketChannel extends AbstractSelectableChannel implements NetworkChannel { /** * Initializes a new instance of this class. * * @param provider * The provider that created this channel */ protected ServerSocketChannel(SelectorProvider provider) { super(provider); } /** * Opens a server-socket channel. * *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. * *
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.
* * @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. * *Server-socket channels only support the accepting of new * connections, so this method returns {@link SelectionKey#OP_ACCEPT}. *
* * @return The valid-operation set */ public final int validOps() { return SelectionKey.OP_ACCEPT; } // -- ServerSocket-specific operations -- /** * Binds the channel's socket to a local address and configures the socket * to listen for connections. * *An invocation of this method is equivalent to the following: *
* bind(local, 0);
* This method is used to establish an association between the socket and * a local address. Once an association is established then the socket remains * bound until the channel is closed. * *
The {@code backlog} parameter is the maximum number of pending
* connections on the socket. Its exact semantics are implementation specific.
* In particular, an implementation may impose a maximum length or may choose
* to ignore the parameter altogther. If the {@code backlog} parameter has
* the value {@code 0}, or a negative value, then an implementation specific
* default is used.
*
* @param local
* The address to bind the socket, or {@code null} to bind to an
* automatically assigned socket address
* @param backlog
* The maximum number of pending connections
*
* @return This channel
*
* @throws AlreadyBoundException
* If the socket is already bound
* @throws UnsupportedAddressTypeException
* If the type of the given address is not supported
* @throws ClosedChannelException
* If this channel is closed
* @throws IOException
* If some other I/O error occurs
* @throws SecurityException
* If a security manager has been installed and its {@link
* SecurityManager#checkListen checkListen} method denies the
* operation
*
* @since 1.7
*/
public abstract ServerSocketChannel bind(SocketAddress local, int backlog)
throws IOException;
/**
* @throws UnsupportedOperationException {@inheritDoc}
* @throws IllegalArgumentException {@inheritDoc}
* @throws ClosedChannelException {@inheritDoc}
* @throws IOException {@inheritDoc}
*
* @since 1.7
*/
public abstract The returned object will not declare any public methods that are not
* declared in the {@link java.net.ServerSocket} class. If this channel is in non-blocking mode then this method will
* immediately return null if there are no pending connections.
* Otherwise it will block indefinitely until a new connection is available
* or an I/O error occurs.
*
* The socket channel returned by this method, if any, will be in
* blocking mode regardless of the blocking mode of this channel.
*
* 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.
* If there is a security manager set, its {@code checkConnect} method is
* called with the local address and {@code -1} as its arguments to see
* if the operation is allowed. If the operation is not allowed,
* a {@code SocketAddress} representing the
* {@link java.net.InetAddress#getLoopbackAddress loopback} address and the
* local port of the channel's socket is returned.
*
* @return The {@code SocketAddress} that the socket is bound to, or the
* {@code SocketAddress} representing the loopback address if
* denied by the security manager, or {@code null} if the
* channel's socket is not bound
*
* @throws ClosedChannelException {@inheritDoc}
* @throws IOException {@inheritDoc}
*/
@Override
public abstract SocketAddress getLocalAddress() throws IOException;
}