DUBBO-组件 protocol export

@SPI("dubbo")
public interface Protocol {
    int getDefaultPort();
     Exporter export(Invoker invoker) throws RpcException;
     Invoker refer(Class type, URL url) throws RpcException;
    void destroy();
}


public abstract class AbstractProtocol implements Protocol {
    protected final Logger logger = LoggerFactory.getLogger(getClass());
    protected final Map> exporterMap = new ConcurrentHashMap>();
    //TODO SOFEREFENCE
    protected final Set> invokers = new ConcurrentHashSet>();
    protected static String serviceKey(URL url) {
        int port = url.getParameter(Constants.BIND_PORT_KEY, url.getPort());
        return serviceKey(port, url.getPath(), url.getParameter(Constants.VERSION_KEY),
                url.getParameter(Constants.GROUP_KEY));
    }
    protected static String serviceKey(int port, String serviceName, String serviceVersion, String serviceGroup) {
        return ProtocolUtils.serviceKey(port, serviceName, serviceVersion, serviceGroup);
    }

    @Override
    public void destroy()  
}




/***
*抽象代理协议 会调用子类的doexport()方法  子类i有 http  rest webservice 
* RMI  hessian
 */
public abstract class AbstractProxyProtocol extends AbstractProtocol {

}




/**
 * dubbo protocol support.
 */
public class DubboProtocol extends AbstractProtocol {
    public static final String NAME = "dubbo";
    public static final int DEFAULT_PORT = 20880;
    private static final String IS_CALLBACK_SERVICE_INVOKE = "_isCallBackServiceInvoke";
    private static DubboProtocol INSTANCE;
    private final Map serverMap = new ConcurrentHashMap(); // 
    private final Map referenceClientMap = new ConcurrentHashMap(); // 
    private final ConcurrentMap ghostClientMap = new ConcurrentHashMap();
    private final ConcurrentMap locks = new ConcurrentHashMap();
    private final Set optimizers = new ConcurrentHashSet();
    //consumer side export a stub service for dispatching event
    //servicekey-stubmethods
    private final ConcurrentMap stubServiceMethodsMap = new ConcurrentHashMap();
    private ExchangeHandler requestHandler = new ExchangeHandlerAdapter() {

        @Override
        public CompletableFuture