NetworkChannel.java

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

import java.io.IOException;
import java.net.SocketAddress;
import java.net.SocketOption;
import java.util.Set;

/**
 * A channel to a network socket.
 *
 * <p> A channel that implements this interface is a channel to a network
 * socket. The {@link #bind(SocketAddress) bind} method is used to bind the
 * socket to a local {@link SocketAddress address}, the {@link #getLocalAddress()
 * getLocalAddress} method returns the address that the socket is bound to, and
 * the {@link #setOption(SocketOption, Object) setOption} and {@link
 * #getOption(SocketOption) getOption} methods are used to set and query socket
 * options.  An implementation of this interface should specify the socket options
 * that it supports.
 *
 * <p> The {@link #bind bind} and {@link #setOption setOption} methods that do
 * not otherwise have a value to return are specified to return the network
 * channel upon which they are invoked. This allows method invocations to be
 * chained. Implementations of this interface should specialize the return type
 * so that method invocations on the implementation class can be chained.
 *
 * @since 1.7
 */
// 网络通道，用于TCP/UDP Socket通信
public interface NetworkChannel extends Channel {
    
    /**
     * Binds the channel's socket to a local address.
     *
     * <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. If the {@code local} parameter has the
     * value {@code null} then the socket will be bound to an address that is
     * assigned automatically.
     *
     * @param local The address to bind the socket, or {@code null} to bind the socket
     *              to an automatically assigned socket address
     *
     * @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 the channel is closed
     * @throws IOException                     If some other I/O error occurs
     * @throws SecurityException               If a security manager is installed and it denies an unspecified
     *                                         permission. An implementation of this interface should specify
     *                                         any required permissions.
     * @see #getLocalAddress
     */
    // 将当前Socket通道绑定到指定的本地地址
    NetworkChannel bind(SocketAddress local) throws IOException;
    
    /**
     * Returns the socket address that this channel's socket is bound to.
     *
     * <p> Where the channel is {@link #bind bound} to an Internet Protocol
     * socket address then the return value from this method is of type {@link
     * java.net.InetSocketAddress}.
     *
     * @return The socket address that the socket is bound to, or {@code null}
     * if the channel's socket is not bound
     *
     * @throws ClosedChannelException If the channel is closed
     * @throws IOException            If an I/O error occurs
     */
    // 获取当前Socket通道绑定的本地地址
    SocketAddress getLocalAddress() throws IOException;
    
    /**
     * Sets the value of a socket option.
     *
     * @param <T>   The type of the socket option value
     * @param name  The socket option
     * @param value The value of the socket option. A value of {@code null} may be
     *              a valid value for some socket options.
     *
     * @return This channel
     *
     * @throws UnsupportedOperationException If the socket option is not supported by this channel
     * @throws IllegalArgumentException      If the value is not a valid value for this socket option
     * @throws ClosedChannelException        If this channel is closed
     * @throws IOException                   If an I/O error occurs
     * @see java.net.StandardSocketOptions
     */
    // 设置指定名称的Socket配置参数
    <T> NetworkChannel setOption(SocketOption<T> name, T value) throws IOException;
    
    /**
     * Returns the value of a socket option.
     *
     * @param <T>  The type of the socket option value
     * @param name The socket option
     *
     * @return The value of the socket option. A value of {@code null} may be
     * a valid value for some socket options.
     *
     * @throws UnsupportedOperationException If the socket option is not supported by this channel
     * @throws ClosedChannelException        If this channel is closed
     * @throws IOException                   If an I/O error occurs
     * @see java.net.StandardSocketOptions
     */
    // 获取指定名称的Socket配置参数
    <T> T getOption(SocketOption<T> name) throws IOException;
    
    /**
     * Returns a set of the socket options supported by this channel.
     *
     * <p> This method will continue to return the set of options even after the
     * channel has been closed.
     *
     * @return A set of the socket options supported by this channel
     */
    // 获取当前通道支持的Socket配置参数集合
    Set<SocketOption<?>> supportedOptions();
    
}