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, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.apache.hadoop.chukwa.datacollection.agent;
19
20 import java.util.Collections;
21 import java.util.Map;
22 import org.apache.hadoop.conf.Configuration;
23 import org.apache.hadoop.chukwa.datacollection.adaptor.Adaptor;
24 import org.apache.hadoop.chukwa.datacollection.adaptor.AdaptorShutdownPolicy;
25
26 /**
27 * The interface to the agent that is exposed to adaptors.
28 *
29 */
30 public interface AdaptorManager {
31
32
33 Configuration getConfiguration();
34 int adaptorCount();
35 @Deprecated
36 long stopAdaptor(String id, boolean gracefully);
37
38
39 long stopAdaptor(String id, AdaptorShutdownPolicy mode);
40 Adaptor getAdaptor(String id);
41 String processAddCommand(String cmd);
42 Map<String, String> getAdaptorList();
43
44 /**
45 * Called to update the Agent status table.
46 *
47 * Most adaptors should not call this. It is designed for adaptors that do
48 * some sort of local operation that needs checkpointing, but that doesn't
49 * emit chunks. For instance, DirTailingAdaptor uses it to track sweeps.
50 *
51 * @param src the adaptor in question
52 * @param uuid the number to record as checkpoint. Must be monotonically increasing.
53 * @return the adaptor ID of the associated adaptor, or null if not running.
54 */
55 public String reportCommit(Adaptor src, long uuid);
56
57 static AdaptorManager NULL = new AdaptorManager() {
58
59 @Override
60 public int adaptorCount() {
61 return 0;
62 }
63
64 @Override
65 public Adaptor getAdaptor(String id) {
66 return null;
67 }
68
69 @Override
70 public Map<String, String> getAdaptorList() {
71 return Collections.emptyMap();
72 }
73
74 @Override
75 public Configuration getConfiguration() {
76 return new Configuration();
77 }
78
79 @Override
80 public String processAddCommand(String cmd) {
81 return "";
82 }
83
84 public long stopAdaptor(String id, boolean gracefully) {
85 return 0;
86 }
87
88 @Override
89 public long stopAdaptor(String id, AdaptorShutdownPolicy mode) {
90 return 0;
91 }
92
93 @Override
94 public String reportCommit(Adaptor a, long l) {
95 return null;
96 }
97 };
98
99 }