import net.jpountz.lz4.LZ4Decompressor; //导入依赖的package包/类
private void handleModernVersion() throws IOException
{
    DataOutputStream out = new DataOutputStream(socket.getOutputStream());
    out.writeInt(MessagingService.current_version);
    out.flush();

    DataInputStream in = new DataInputStream(socket.getInputStream());
    int maxVersion = in.readInt();
    from = CompactEndpointSerializationHelper.deserialize(in);

    if (compressed)
    {
        logger.debug("Upgrading incoming connection to be compressed");
        if (version < MessagingService.VERSION_21)
            in = new DataInputStream(new SnappyInputStream(socket.getInputStream()));
        else
        {
            LZ4Decompressor decompressor = LZ4Factory.fastestInstance().decompressor();
            Checksum checksum = XXHashFactory.fastestInstance().newStreamingHash32(OutboundTcpConnection.LZ4_HASH_SEED).asChecksum();
            in = new DataInputStream(new LZ4BlockInputStream(socket.getInputStream(),
                                                             decompressor,
                                                             checksum));
        }
    }
    else
    {
        in = new DataInputStream(new BufferedInputStream(socket.getInputStream(), 4096));
    }

    logger.debug("Max version for {} is {}", from, maxVersion);
    if (version > MessagingService.current_version)
    {
        // save the endpoint so gossip will reconnect to it
        Gossiper.instance.addSavedEndpoint(from);
        logger.info("Received messages from newer protocol version {}. Ignoring", version);
        return;
    }
    MessagingService.instance().setVersion(from, Math.min(MessagingService.current_version, maxVersion));
    logger.debug("set version for {} to {}", from, Math.min(MessagingService.current_version, maxVersion));
    // outbound side will reconnect if necessary to upgrade version

    while (true)
    {
        MessagingService.validateMagic(in.readInt());
        receiveMessage(in, version);
    }
}