dubbo學習筆記 十一 dubbo-rpc之模塊

dubbo-rpc分爲幾個模塊

protocol

在具體的實現protocol之前，有兩個包裝類ProtocolFilterWrapper 和ProtocolListenerWrapper

filter=com.alibaba.dubbo.rpc.protocol.ProtocolFilterWrapper
listener=com.alibaba.dubbo.rpc.protocol.ProtocolListenerWrapper
mock=com.alibaba.dubbo.rpc.support.MockProtocol

ProtocolFilterWrapper  核心方法是buildInvokerChain，構建Chain  

AbstractProtocol  定義其抽象類，我們看下dubboProtocol的實現

    public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
        URL url = invoker.getUrl();
        
        // export service.
        String key = serviceKey(url);
        DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
        exporterMap.put(key, exporter);
        
        //export an stub service for dispaching event
        Boolean isStubSupportEvent = url.getParameter(Constants.STUB_EVENT_KEY,Constants.DEFAULT_STUB_EVENT);
        Boolean isCallbackservice = url.getParameter(Constants.IS_CALLBACK_SERVICE, false);
        if (isStubSupportEvent && !isCallbackservice){
            String stubServiceMethods = url.getParameter(Constants.STUB_EVENT_METHODS_KEY);
            if (stubServiceMethods == null || stubServiceMethods.length() == 0 ){
                if (logger.isWarnEnabled()){
                    logger.warn(new IllegalStateException("consumer [" +url.getParameter(Constants.INTERFACE_KEY) +
                            "], has set stubproxy support event ,but no stub methods founded."));
                }
            } else {
                stubServiceMethodsMap.put(url.getServiceKey(), stubServiceMethods);
            }
        }

        openServer(url);
        
        return exporter;
    }

filter

protocol已經buildChain了，然後filter逐個執行吧

@SPI
public interface Filter {

	/**
	 * do invoke filter.
	 * 
	 * <code>
	 * // before filter
     * Result result = invoker.invoke(invocation);
     * // after filter
     * return result;
     * </code>
     * 
     * @see com.alibaba.dubbo.rpc.Invoker#invoke(Invocation)
	 * @param invoker service
	 * @param invocation invocation.
	 * @return invoke result.
	 * @throws RpcException
	 */
	Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException;

}

listener

主要是ListenerInvokerWrapper和ListenerExporterWrapper ，監聽模式爲以後做個擴展唄，目前dubbo沒有使用

proxy

基於字節碼還是基於反射，來動態創建實例

@SPI("javassist")
public interface ProxyFactory {

    /**
     * create proxy.
     * 
     * @param invoker
     * @return proxy
     */
    @Adaptive({Constants.PROXY_KEY})
    <T> T getProxy(Invoker<T> invoker) throws RpcException;

    /**
     * create invoker.
     * 
     * @param <T>
     * @param proxy
     * @param type
     * @param url
     * @return invoker
     */
    @Adaptive({Constants.PROXY_KEY})
    <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) throws RpcException;

}

service

/**
 * 通用服務接口
 * 
 * @author william.liangf
 * @export
 */
public interface GenericService {

    /**
     * 泛化調用
     * 
     * @param method 方法名，如：findPerson，如果有重載方法，需帶上參數列表，如：findPerson(java.lang.String)
     * @param parameterTypes 參數類型
     * @param args 參數列表
     * @return 返回值
     * @throws Throwable 方法拋出的異常
     */
    Object $invoke(String method, String[] parameterTypes, Object[] args) throws GenericException;

}

support

一些mock類和util類