org.apache.hadoop.ipc.AlignmentContext Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.ipc;
import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.ipc.protobuf.RpcHeaderProtos.RpcRequestHeaderProto;
import org.apache.hadoop.ipc.protobuf.RpcHeaderProtos.RpcResponseHeaderProto;
/**
* This interface intends to align the state between client and server
* via RPC communication.
*
* This should be implemented separately on the client side and server side
* and can be used to pass state information on RPC responses from server
* to client.
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public interface AlignmentContext {
/**
* This is the intended server method call to implement to pass state info
* during RPC response header construction.
*
* @param header The RPC response header builder.
*/
void updateResponseState(RpcResponseHeaderProto.Builder header);
/**
* This is the intended client method call to implement to recieve state info
* during RPC response processing.
*
* @param header The RPC response header.
*/
void receiveResponseState(RpcResponseHeaderProto header);
/**
* This is the intended client method call to pull last seen state info
* into RPC request processing.
*
* @param header The RPC request header builder.
*/
void updateRequestState(RpcRequestHeaderProto.Builder header);
/**
* This is the intended server method call to implement to receive
* client state info during RPC response header processing.
*
* @param header The RPC request header.
* @param threshold a parameter to verify a condition when server
* should reject client request due to its state being too far
* misaligned with the client state.
* See implementation for more details.
* @return state id required for the server to execute the call.
* @throws IOException
*/
long receiveRequestState(RpcRequestHeaderProto header, long threshold)
throws IOException;
/**
* Returns the last seen state id of the alignment context instance.
*
* @return the value of the last seen state id.
*/
long getLastSeenStateId();
/**
* Return true if this method call does need to be synced, false
* otherwise. sync meaning server state needs to have caught up with
* client state.
*
* @param protocolName the name of the protocol
* @param method the method call to check
* @return true if this method is async, false otherwise.
*/
boolean isCoordinatedCall(String protocolName, String method);
}