org.apache.dubbo.rpc

接口 Protocol

所有已知实现类:

AbstractProtocol, AbstractProxyProtocol, MockProtocol, ProtocolFilterWrapper, ProtocolListenerWrapper

@SPI(value="dubbo")
public interface Protocol

Protocol. (API/SPI, Singleton, ThreadSafe)

方法概要

限定符和类型	方法和说明
void	destroy() Destroy protocol: 1.
<T> Exporter<T>	export(Invoker<T> invoker) Export service for remote invocation: 1.
int	getDefaultPort() Get default port when user doesn't config the port.
default List<ProtocolServer>	getServers() Get all servers serving this protocol
<T> Invoker<T>	refer(Class<T> type, URL url) Refer a remote service: 1.

方法详细资料

getDefaultPort

int getDefaultPort()

Get default port when user doesn't config the port.

返回:

default port

export

@Adaptive
<T> Exporter<T> export(Invoker<T> invoker)
                          throws RpcException

Export service for remote invocation:
1. Protocol should record request source address after receive a request: RpcContext.getContext().setRemoteAddress();
2. export() must be idempotent, that is, there's no difference between invoking once and invoking twice when export the same URL
3. Invoker instance is passed in by the framework, protocol needs not to care

类型参数:

T - Service type

参数:

invoker - Service invoker

返回:

exporter reference for exported service, useful for unexport the service later

抛出:

RpcException - thrown when error occurs during export the service, for example: port is occupied

refer

@Adaptive
<T> Invoker<T> refer(Class<T> type,
                               URL url)
                        throws RpcException

Refer a remote service:
1. When user calls `invoke()` method of `Invoker` object which's returned from `refer()` call, the protocol needs to correspondingly execute `invoke()` method of `Invoker` object
2. It's protocol's responsibility to implement `Invoker` which's returned from `refer()`. Generally speaking, protocol sends remote request in the `Invoker` implementation.
3. When there's check=false set in URL, the implementation must not throw exception but try to recover when connection fails.

类型参数:

T - Service type

参数:

type - Service class

url - URL address for the remote service

返回:

invoker service's local proxy

抛出:

RpcException - when there's any error while connecting to the service provider

destroy

void destroy()

Destroy protocol:
1. Cancel all services this protocol exports and refers
2. Release all occupied resources, for example: connection, port, etc.
3. Protocol can continue to export and refer new service even after it's destroyed.

getServers

default List<ProtocolServer> getServers()

Get all servers serving this protocol

返回: