RPC Call categories

1. A synchronous invocation ： The client waits for the server to complete the call and return the result
2. Asynchronous call ： The client does not have to wait for the execution result to return , However, the return result can still be obtained through callback notification and other methods , If the client does not the relationship, the call returns the result , Becomes a one-way asynchronous call , One way calls do not return results .

RPC Structural dismantling

• RPC The service provider passes  RpcServer  To export （export） Remote interface method .
• By the client  RpcClient  To introduce （import） Remote interface method .
• The client calls the remote interface method just like the local method ,RPC Proxy implementation of interface provided by framework , The actual call is delegated to the agent  RpcProxy .
• The agent encapsulates the call information and passes the call to  RpcInvoker  To actually execute .
• On the client side  RpcInvoker  Through connector  RpcConnector  To maintain the channel with the server  RpcChannel, And use  RpcProtocol  Execute protocol code （encode） And send the encoded request message to the server through the channel .
• RPC Server receiver  RpcAcceptor  Receive call requests from clients , Also use  RpcProtocol  Perform protocol decoding （decode）.
• The decoded call information is passed to  RpcProcessor  To control the processing of the call process
• Finally, delegate the call to  RpcInvoker  To actually execute and return the call result .

RPC Component responsibilities

• RpcServer： Responsible for exporting （export） Remote interface
• RpcClient： Responsible for importing （import） Proxy implementation of remote interface
• RpcProxy： Proxy implementation of remote interface
• RpcInvoker： The client realizes （ Responsible for encoding the call information and sending the call request to the service side and waiting for the call result to return ）; The service side realizes （ Responsible for calling the specific implementation of the server interface and returning the call result ）

• RpcProtocol： Be responsible for the compilation of the agreement / decode
• RpcConnector： Responsible for maintaining the connection channel between the client and the service side and sending data to the service side
• RpcAcceptor： Responsible for receiving the client's request and returning the request result
• RpcProcessor： Responsible for controlling the calling process at the service side , Include management call thread pool 、 Timeout time, etc
• RpcChannel： Data transmission channel