298 lines
11 KiB
Java
298 lines
11 KiB
Java
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/*
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* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.nio.channels;
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import java.io.IOException;
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import java.net.ServerSocket;
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import java.net.SocketOption;
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import java.net.SocketAddress;
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import java.nio.channels.spi.AbstractSelectableChannel;
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import java.nio.channels.spi.SelectorProvider;
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/**
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* A selectable channel for stream-oriented listening sockets.
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*
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* <p> A server-socket channel is created by invoking the {@link #open() open}
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* method of this class. It is not possible to create a channel for an arbitrary,
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* pre-existing {@link ServerSocket}. A newly-created server-socket channel is
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* open but not yet bound. An attempt to invoke the {@link #accept() accept}
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* method of an unbound server-socket channel will cause a {@link NotYetBoundException}
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* to be thrown. A server-socket channel can be bound by invoking one of the
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* {@link #bind(java.net.SocketAddress,int) bind} methods defined by this class.
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*
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* <p> Socket options are configured using the {@link #setOption(SocketOption,Object)
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* setOption} method. Server-socket channels support the following options:
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* <blockquote>
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* <table class="striped">
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* <caption style="display:none">Socket options</caption>
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* <thead>
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* <tr>
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* <th scope="col">Option Name</th>
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* <th scope="col">Description</th>
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* </tr>
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* </thead>
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* <tbody>
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* <tr>
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* <th scope="row"> {@link java.net.StandardSocketOptions#SO_RCVBUF SO_RCVBUF} </th>
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* <td> The size of the socket receive buffer </td>
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* </tr>
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* <tr>
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* <th scope="row"> {@link java.net.StandardSocketOptions#SO_REUSEADDR SO_REUSEADDR} </th>
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* <td> Re-use address </td>
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* </tr>
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* </tbody>
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* </table>
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* </blockquote>
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* Additional (implementation specific) options may also be supported.
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*
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* <p> Server-socket channels are safe for use by multiple concurrent threads.
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* </p>
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*
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* @author Mark Reinhold
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* @author JSR-51 Expert Group
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* @since 1.4
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*/
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public abstract class ServerSocketChannel
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extends AbstractSelectableChannel
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implements NetworkChannel
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{
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/**
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* Initializes a new instance of this class.
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*
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* @param provider
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* The provider that created this channel
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*/
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protected ServerSocketChannel(SelectorProvider provider) {
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super(provider);
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}
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/**
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* Opens a server-socket channel.
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*
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* <p> The new channel is created by invoking the {@link
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* java.nio.channels.spi.SelectorProvider#openServerSocketChannel
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* openServerSocketChannel} method of the system-wide default {@link
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* java.nio.channels.spi.SelectorProvider} object.
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*
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* <p> The new channel's socket is initially unbound; it must be bound to a
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* specific address via one of its socket's {@link
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* java.net.ServerSocket#bind(SocketAddress) bind} methods before
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* connections can be accepted. </p>
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*
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* @return A new socket channel
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*
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* @throws IOException
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* If an I/O error occurs
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*/
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public static ServerSocketChannel open() throws IOException {
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return SelectorProvider.provider().openServerSocketChannel();
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}
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/**
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* Returns an operation set identifying this channel's supported
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* operations.
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*
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* <p> Server-socket channels only support the accepting of new
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* connections, so this method returns {@link SelectionKey#OP_ACCEPT}.
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* </p>
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*
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* @return The valid-operation set
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*/
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public final int validOps() {
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return SelectionKey.OP_ACCEPT;
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}
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// -- ServerSocket-specific operations --
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/**
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* Binds the channel's socket to a local address and configures the socket
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* to listen for connections.
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*
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* <p> An invocation of this method is equivalent to the following:
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* <blockquote><pre>
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* bind(local, 0);
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* </pre></blockquote>
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*
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* @param local
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* The local address to bind the socket, or {@code null} to bind
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* to an automatically assigned socket address
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*
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* @return This channel
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*
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* @throws AlreadyBoundException {@inheritDoc}
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* @throws UnsupportedAddressTypeException {@inheritDoc}
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* @throws ClosedChannelException {@inheritDoc}
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* @throws IOException {@inheritDoc}
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* @throws SecurityException
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* If a security manager has been installed and its {@link
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* SecurityManager#checkListen checkListen} method denies the
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* operation
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*
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* @since 1.7
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*/
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public final ServerSocketChannel bind(SocketAddress local)
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throws IOException
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{
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return bind(local, 0);
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}
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/**
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* Binds the channel's socket to a local address and configures the socket to
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* listen for connections.
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*
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* <p> This method is used to establish an association between the socket and
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* a local address. Once an association is established then the socket remains
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* bound until the channel is closed.
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*
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* <p> The {@code backlog} parameter is the maximum number of pending
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* connections on the socket. Its exact semantics are implementation specific.
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* In particular, an implementation may impose a maximum length or may choose
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* to ignore the parameter altogther. If the {@code backlog} parameter has
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* the value {@code 0}, or a negative value, then an implementation specific
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* default is used.
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*
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* @param local
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* The address to bind the socket, or {@code null} to bind to an
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* automatically assigned socket address
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* @param backlog
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* The maximum number of pending connections
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*
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* @return This channel
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*
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* @throws AlreadyBoundException
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* If the socket is already bound
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* @throws UnsupportedAddressTypeException
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* If the type of the given address is not supported
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* @throws ClosedChannelException
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* If this channel is closed
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* @throws IOException
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* If some other I/O error occurs
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* @throws SecurityException
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* If a security manager has been installed and its {@link
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* SecurityManager#checkListen checkListen} method denies the
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* operation
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*
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* @since 1.7
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*/
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public abstract ServerSocketChannel bind(SocketAddress local, int backlog)
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throws IOException;
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/**
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* @throws UnsupportedOperationException {@inheritDoc}
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* @throws IllegalArgumentException {@inheritDoc}
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* @throws ClosedChannelException {@inheritDoc}
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* @throws IOException {@inheritDoc}
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*
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* @since 1.7
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*/
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public abstract <T> ServerSocketChannel setOption(SocketOption<T> name, T value)
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throws IOException;
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/**
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* Retrieves a server socket associated with this channel.
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*
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* <p> The returned object will not declare any public methods that are not
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* declared in the {@link java.net.ServerSocket} class. </p>
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*
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* @return A server socket associated with this channel
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*/
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public abstract ServerSocket socket();
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/**
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* Accepts a connection made to this channel's socket.
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*
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* <p> If this channel is in non-blocking mode then this method will
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* immediately return {@code null} if there are no pending connections.
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* Otherwise it will block indefinitely until a new connection is available
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* or an I/O error occurs.
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*
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* <p> The socket channel returned by this method, if any, will be in
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* blocking mode regardless of the blocking mode of this channel.
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*
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* <p> This method performs exactly the same security checks as the {@link
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* java.net.ServerSocket#accept accept} method of the {@link
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* java.net.ServerSocket} class. That is, if a security manager has been
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* installed then for each new connection this method verifies that the
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* address and port number of the connection's remote endpoint are
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* permitted by the security manager's {@link
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* java.lang.SecurityManager#checkAccept checkAccept} method. </p>
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*
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* @return The socket channel for the new connection,
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* or {@code null} if this channel is in non-blocking mode
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* and no connection is available to be accepted
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*
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* @throws ClosedChannelException
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* If this channel is closed
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*
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* @throws AsynchronousCloseException
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* If another thread closes this channel
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* while the accept operation is in progress
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*
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* @throws ClosedByInterruptException
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* If another thread interrupts the current thread
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* while the accept operation is in progress, thereby
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* closing the channel and setting the current thread's
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* interrupt status
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*
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* @throws NotYetBoundException
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* If this channel's socket has not yet been bound
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*
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* @throws SecurityException
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* If a security manager has been installed
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* and it does not permit access to the remote endpoint
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* of the new connection
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*
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* @throws IOException
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* If some other I/O error occurs
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*/
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public abstract SocketChannel accept() throws IOException;
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/**
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* {@inheritDoc}
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* <p>
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* If there is a security manager set, its {@code checkConnect} method is
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* called with the local address and {@code -1} as its arguments to see
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* if the operation is allowed. If the operation is not allowed,
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* a {@code SocketAddress} representing the
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* {@link java.net.InetAddress#getLoopbackAddress loopback} address and the
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* local port of the channel's socket is returned.
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*
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* @return The {@code SocketAddress} that the socket is bound to, or the
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* {@code SocketAddress} representing the loopback address if
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* denied by the security manager, or {@code null} if the
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* channel's socket is not bound
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*
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* @throws ClosedChannelException {@inheritDoc}
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* @throws IOException {@inheritDoc}
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*/
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@Override
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public abstract SocketAddress getLocalAddress() throws IOException;
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}
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