dubbo-remoting分析～没完待续

Endpoint

Channel，Client，Server都会继承Endpoint：

com.alibaba.dubbo.remoting.Channel
com.alibaba.dubbo.remoting.Client
com.alibaba.dubbo.remoting.Server

public interface Endpoint {

    //get url.
    URL getUrl();
    //get channel handler.
    ChannelHandler getChannelHandler();
    //get local address.
    InetSocketAddress getLocalAddress();
    //send message.
    void send(Object message) throws RemotingException;
    //send message； sent    是否已发送完成
    void send(Object message, boolean sent) throws RemotingException;
    // close the channel.
    void close();
     //Graceful close the channel.
    void close(int timeout);
    void startClose();
    // is closed.
    boolean isClosed();
}

Channel

相关类

com.alibaba.dubbo.remoting.Client
com.alibaba.dubbo.remoting.Server#getChannels()
com.alibaba.dubbo.remoting.Server#getChannel(InetSocketAddress)

public interface Server extends Endpoint, Resetable {

    //is bound.
    boolean isBound();

    // get channels.
    Collection<Channel> getChannels();

    // get channel.
    Channel getChannel(InetSocketAddress remoteAddress);

    @Deprecated
    void reset(com.alibaba.dubbo.common.Parameters parameters);
}

ChannelHandler

相关类

com.alibaba.dubbo.remoting.Transporter#bind(com.alibaba.dubbo.common.URL, ChannelHandler)
com.alibaba.dubbo.remoting.Transporter#connect(com.alibaba.dubbo.common.URL, ChannelHandler)

public interface ChannelHandler {

    /**
     * on channel connected.
     *
     * @param channel channel.
     */
    void connected(Channel channel) throws RemotingException;

    /**
     * on channel disconnected.
     *
     * @param channel channel.
     */
    void disconnected(Channel channel) throws RemotingException;

    /**
     * on message sent.
     *
     * @param channel channel.
     * @param message message.
     */
    void sent(Channel channel, Object message) throws RemotingException;

    /**
     * on message received.
     *
     * @param channel channel.
     * @param message message.
     */
    void received(Channel channel, Object message) throws RemotingException;

    /**
     * on exception caught.
     *
     * @param channel   channel.
     * @param exception exception.
     */
    void caught(Channel channel, Throwable exception) throws RemotingException;

}

Server

相关类

com.alibaba.dubbo.remoting.Transporter#bind(com.alibaba.dubbo.common.URL, ChannelHandler)

public interface Server extends Endpoint, Resetable {

    //is bound.
    boolean isBound();
    // get channels.
    Collection<Channel> getChannels();
    // get channel.
    Channel getChannel(InetSocketAddress remoteAddress);
    @Deprecated
    void reset(com.alibaba.dubbo.common.Parameters parameters);
}

Client

com.alibaba.dubbo.remoting.Transporter#connect(com.alibaba.dubbo.common.URL, ChannelHandler)

public interface Client extends Endpoint, Channel, Resetable {

    /**
     * reconnect.
     */
    void reconnect() throws RemotingException;

    @Deprecated
    void reset(com.alibaba.dubbo.common.Parameters parameters);

}

Dispatcher

默认是：AllDispatcher

@SPI(AllDispatcher.NAME)
public interface Dispatcher {

    // dispatch the message to threadpool.
    @Adaptive({Constants.DISPATCHER_KEY, "dispather", "channel.handler"})
    // 后两个参数为兼容旧配置
    ChannelHandler dispatch(ChannelHandler handler, URL url);

}

Codec2

编码

@SPI
public interface Codec2 {

    @Adaptive({Constants.CODEC_KEY})
    void encode(Channel channel, ChannelBuffer buffer, Object message) throws IOException;

    @Adaptive({Constants.CODEC_KEY})
    Object decode(Channel channel, ChannelBuffer buffer) throws IOException;


    enum DecodeResult {
        NEED_MORE_INPUT, SKIP_SOME_INPUT
    }

}

结构图

AbstractCodec

/**
     * 通过传输数据的大小，默认是8m
     * @param channel
     * @param size
     * @throws IOException
     */
    protected static void checkPayload(Channel channel, long size) throws IOException {
        int payload = Constants.DEFAULT_PAYLOAD;
        if (channel != null && channel.getUrl() != null) {
            //从url中获取8m
            payload = channel.getUrl().getParameter(Constants.PAYLOAD_KEY, Constants.DEFAULT_PAYLOAD);
        }
        if (payload > 0 && size > payload) {
            ExceedPayloadLimitException e = new ExceedPayloadLimitException("Data length too large: " + size + ", max payload: " + payload + ", channel: " + channel);
            logger.error(e);
            throw e;
        }
    }

    /**
     * 获取Serialization，默认是hessian2(spi)
     */
    protected Serialization getSerialization(Channel channel) {
        return CodecSupport.getSerialization(channel.getUrl());
    }

    /*
     *检查是否是客户端调用
     */
    protected boolean isClientSide(Channel channel) {
        String side = (String) channel.getAttribute(Constants.SIDE_KEY);
        if ("client".equals(side)) {
            return true;
        } else if ("server".equals(side)) {
            return false;
        } else {
            InetSocketAddress address = channel.getRemoteAddress();
            URL url = channel.getUrl();
            boolean client = url.getPort() == address.getPort()
                    && NetUtils.filterLocalHost(url.getIp()).equals(
                    NetUtils.filterLocalHost(address.getAddress()
                            .getHostAddress()));
            channel.setAttribute(Constants.SIDE_KEY, client ? "client"
                    : "server");
            return client;
        }
    }

    protected boolean isServerSide(Channel channel) {
        return !isClientSide(channel);
    }

}

Decodeable

解码

public interface Decodeable {

    public void decode() throws Exception;

}

Transporter

默认是netty
相关类

com.alibaba.dubbo.remoting.Transporters

@SPI("netty")
public interface Transporter {

    /**
     * Bind a server.
     *
     * @param url     server url
     * @param handler
     * @return server
     * @throws RemotingException
     * @see com.alibaba.dubbo.remoting.Transporters#bind(URL, Receiver, ChannelHandler)
     */
    @Adaptive({Constants.SERVER_KEY, Constants.TRANSPORTER_KEY})
    Server bind(URL url, ChannelHandler handler) throws RemotingException;

    /**
     * Connect to a server.
     *
     * @param url     server url
     * @param handler
     * @return client
     * @throws RemotingException
     * @see com.alibaba.dubbo.remoting.Transporters#connect(URL, Receiver, ChannelListener)
     */
    @Adaptive({Constants.CLIENT_KEY, Constants.TRANSPORTER_KEY})
    Client connect(URL url, ChannelHandler handler) throws RemotingException;

}

需要学习的文档

http://geek.csdn.net/news/detail/185484