1 /*
2 *
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16 package org.apache.hadoop.hbase.coprocessor;
17
18 import java.io.IOException;
19
20 import org.apache.hadoop.classification.InterfaceAudience;
21 import org.apache.hadoop.classification.InterfaceStability;
22 import org.apache.hadoop.hbase.Coprocessor;
23 import org.apache.hadoop.hbase.CoprocessorEnvironment;
24 import org.apache.hadoop.hbase.ipc.CoprocessorProtocol;
25 import org.apache.hadoop.hbase.ipc.ProtocolSignature;
26 import org.apache.hadoop.hbase.ipc.VersionedProtocol;
27
28 /**
29 * This abstract class provides default implementation of an Endpoint.
30 * It also maintains a CoprocessorEnvironment object which can be
31 * used to access region resource.
32 *
33 * It's recommended to use this abstract class to implement your Endpoint.
34 * However you still can just implement the interface CoprocessorProtocol
35 * and Coprocessor to develop an Endpoint. But you won't be able to access
36 * the region related resource, i.e., CoprocessorEnvironment.
37 */
38 @InterfaceAudience.Public
39 @InterfaceStability.Evolving
40 public abstract class BaseEndpointCoprocessor implements Coprocessor,
41 CoprocessorProtocol, VersionedProtocol {
42 /**
43 * This Interfaces' version. Version changes when the Interface changes.
44 */
45 // All HBase Interfaces used derive from HBaseRPCProtocolVersion. It
46 // maintained a single global version number on all HBase Interfaces. This
47 // meant all HBase RPC was broke though only one of the three RPC Interfaces
48 // had changed. This has since been undone.
49 public static final long VERSION = 28L;
50
51 private CoprocessorEnvironment env;
52
53 /**
54 * @return env Coprocessor environment.
55 */
56 public CoprocessorEnvironment getEnvironment() {
57 return env;
58 }
59
60 @Override
61 public void start(CoprocessorEnvironment env) {
62 this.env = env;
63 }
64
65 @Override
66 public void stop(CoprocessorEnvironment env) { }
67
68 @Override
69 public ProtocolSignature getProtocolSignature(
70 String protocol, long version, int clientMethodsHashCode)
71 throws IOException {
72 return new ProtocolSignature(VERSION, null);
73 }
74
75 @Override
76 public long getProtocolVersion(String protocol, long clientVersion)
77 throws IOException {
78 return VERSION;
79 }
80 }