https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package java.nio.channels;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.SocketOption;
import java.net.SocketAddress;
import java.nio.channels.spi.AbstractSelectableChannel;
import java.nio.channels.spi.SelectorProvider;


A selectable channel for stream-oriented listening sockets.

 A server-socket channel is created by invoking the open method of this class. It is not possible to create a channel for an arbitrary, pre-existing ServerSocket. A newly-created server-socket channel is open but not yet bound. An attempt to invoke the accept method of an unbound server-socket channel will cause a NotYetBoundException to be thrown. A server-socket channel can be bound by invoking one of the bind methods defined by this class. 
 Socket options are configured using the 
setOption method. Server-socket channels support the following options: 



Socket options

  

    Option Name
    Description
  



  

     SO_RCVBUF 
     The size of the socket receive buffer 
  

  

     SO_REUSEADDR 
     Re-use address 
  






Additional (implementation specific) options may also be supported.

 Server-socket channels are safe for use by multiple concurrent threads.



Author:Mark Reinhold, JSR-51 Expert Group
Since:1.4
/**
 * A selectable channel for stream-oriented listening sockets.
 *
 * <p> 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.
 *
 * <p> Socket options are configured using the {@link #setOption(SocketOption,Object)
 * setOption} method. Server-socket channels support the following options:
 * <blockquote>
 * <table class="striped">
 * <caption style="display:none">Socket options</caption>
 * <thead>
 *   <tr>
 *     <th scope="col">Option Name</th>
 *     <th scope="col">Description</th>
 *   </tr>
 * </thead>
 * <tbody>
 *   <tr>
 *     <th scope="row"> {@link java.net.StandardSocketOptions#SO_RCVBUF SO_RCVBUF} </th>
 *     <td> The size of the socket receive buffer </td>
 *   </tr>
 *   <tr>
 *     <th scope="row"> {@link java.net.StandardSocketOptions#SO_REUSEADDR SO_REUSEADDR} </th>
 *     <td> Re-use address </td>
 *   </tr>
 * </tbody>
 * </table>
 * </blockquote>
 * Additional (implementation specific) options may also be supported.
 *
 * <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
    implements NetworkChannel
{

    
Initializes a new instance of this class.

Params:
  • provider – 
        The provider that created this channel
/**
     * 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 
openServerSocketChannel method of the system-wide default SelectorProvider object. 
 The new channel's socket is initially unbound; it must be bound to a specific address via one of its socket's bind methods before connections can be accepted. 


Throws:
Returns: A new socket channel
/**
     * 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.

 Server-socket channels only support the accepting of new connections, so this method returns SelectionKey.OP_ACCEPT. 


Returns: The valid-operation set
/**
     * 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 --

    
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);



Params:
  • local –  The local address to bind the socket, or null to bind to an automatically assigned socket address
Throws:
Returns: This channel
Since:1.7
/**
     * Binds the channel's socket to a local address and configures the socket
     * to listen for connections.
     *
     * <p> An invocation of this method is equivalent to the following:
     * <blockquote><pre>
     * bind(local, 0);
     * </pre></blockquote>
     *
     * @param   local
     *          The local address to bind the socket, or {@code null} to bind
     *          to an automatically assigned socket address
     *
     * @return  This channel
     *
     * @throws  AlreadyBoundException               {@inheritDoc}
     * @throws  UnsupportedAddressTypeException     {@inheritDoc}
     * @throws  ClosedChannelException              {@inheritDoc}
     * @throws  IOException                         {@inheritDoc}
     * @throws  SecurityException
     *          If a security manager has been installed and its {@link
     *          SecurityManager#checkListen checkListen} method denies the
     *          operation
     *
     * @since 1.7
     */
    public final ServerSocketChannel bind(SocketAddress local)
        throws IOException
    {
        return bind(local, 0);
    }

    
Binds the channel's socket to a local address and configures the socket to
listen for connections.

 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 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 backlog parameter has the value 0, or a negative value, then an implementation specific default is used. 
Params:
  • local –  The address to bind the socket, or null to bind to an automatically assigned socket address
  • backlog – 
         The maximum number of pending connections
Throws:
Returns: This channel
Since:1.7
/**
     * Binds the channel's socket to a local address and configures the socket to
     * listen for connections.
     *
     * <p> 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.
     *
     * <p> 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:
Since:1.7
/**
     * @throws  UnsupportedOperationException           {@inheritDoc}
     * @throws  IllegalArgumentException                {@inheritDoc}
     * @throws  ClosedChannelException                  {@inheritDoc}
     * @throws  IOException                             {@inheritDoc}
     *
     * @since 1.7
     */
    public abstract <T> ServerSocketChannel setOption(SocketOption<T> name, T value)
        throws IOException;

    
Retrieves a server socket associated with this channel.

 The returned object will not declare any public methods that are not declared in the ServerSocket class. 


Returns: A server socket associated with this channel
/**
     * 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.

 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 accept method of the 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 checkAccept method. 


Throws:
  • ClosedChannelException – 
         If this channel is closed
  • AsynchronousCloseException – 
         If another thread closes this channel
         while the accept operation is in progress
  • 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
  • NotYetBoundException – 
         If this channel's socket has not yet been bound
  • SecurityException – 
         If a security manager has been installed
         and it does not permit access to the remote endpoint
         of the new connection
  • IOException – 
         If some other I/O error occurs
Returns: The socket channel for the new connection, or null if this channel is in non-blocking mode and no connection is available to be accepted
/**
     * Accepts a connection made to this channel's socket.
     *
     * <p> If this channel is in non-blocking mode then this method will
     * immediately return {@code null} 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 {@code null} 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;

    
{@inheritDoc}

 If there is a security manager set, its checkConnect method is called with the local address and -1 as its arguments to see if the operation is allowed. If the operation is not allowed, a SocketAddress representing the loopback address and the local port of the channel's socket is returned. 
Throws:
Returns: The SocketAddress that the socket is bound to, or the SocketAddress representing the loopback address if denied by the security manager, or null if the channel's socket is not bound
/**
     * {@inheritDoc}
     * <p>
     * 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;

}