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/* * @(#)ServerSocketChannel.java 1.25 05/11/17 * * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ 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 * @version 1.25, 05/11/17 * @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; }