1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19
20 package org.apache.hadoop.hbase.coprocessor;
21
22 import java.io.IOException;
23
24 import org.apache.hadoop.hbase.classification.InterfaceAudience;
25 import org.apache.hadoop.hbase.classification.InterfaceStability;
26 import org.apache.hadoop.hbase.Coprocessor;
27 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
28
29 import com.google.protobuf.Message;
30 import com.google.protobuf.Service;
31
32 /**
33 * Coprocessors implement this interface to observe and mediate endpoint invocations
34 * on a region.
35 */
36 @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC)
37 @InterfaceStability.Evolving
38 public interface EndpointObserver extends Coprocessor {
39
40 /**
41 * Called before an Endpoint service method is invoked.
42 * The request message can be altered by returning a new instance. Throwing an
43 * exception will abort the invocation.
44 * Calling {@link org.apache.hadoop.hbase.coprocessor.ObserverContext#bypass()} has no
45 * effect in this hook.
46 * @param ctx the environment provided by the region server
47 * @param service the endpoint service
48 * @param methodName the invoked service method
49 * @param request the request message
50 * @return the possibly modified message
51 * @throws IOException
52 */
53 Message preEndpointInvocation(ObserverContext<RegionCoprocessorEnvironment> ctx, Service service,
54 String methodName, Message request) throws IOException;
55
56 /**
57 * Called after an Endpoint service method is invoked. The response message can be
58 * altered using the builder.
59 * @param ctx the environment provided by the region server
60 * @param service the endpoint service
61 * @param methodName the invoked service method
62 * @param request the request message
63 * @param responseBuilder the response message builder
64 * @throws IOException
65 */
66 void postEndpointInvocation(ObserverContext<RegionCoprocessorEnvironment> ctx, Service service,
67 String methodName, Message request, Message.Builder responseBuilder) throws IOException;
68
69 }