| /** |
| * 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.lang.annotation.Retention; |
| import java.lang.annotation.RetentionPolicy; |
| |
| |
| /** |
| * The protocol name that is used when a client and server connect. |
| * By default the class name of the protocol interface is the protocol name. |
| * |
| * Why override the default name (i.e. the class name)? |
| * One use case overriding the default name (i.e. the class name) is when |
| * there are multiple implementations of the same protocol, each with say a |
| * different version/serialization. |
| * In Hadoop this is used to allow multiple server and client adapters |
| * for different versions of the same protocol service. |
| */ |
| @Retention(RetentionPolicy.RUNTIME) |
| public @interface ProtocolInfo { |
| String protocolName(); // the name of the protocol (i.e. rpc service) |
| long protocolVersion() default -1; // default means not defined use old way |
| } |
