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
19 package org.apache.giraph.utils;
20
21 import org.apache.hadoop.mapreduce.Job;
22
23 import java.io.IOException;
24
25 /** Utility methods for dealing with counters */
26 public class CounterUtils {
27 /** Milliseconds to sleep for while waiting for counter to appear */
28 private static final int SLEEP_MSECS = 100;
29
30 /** Do not instantiate */
31 private CounterUtils() {
32 }
33
34 /**
35 * Wait for a counter to appear in a group and then return the name of that
36 * counter. If job finishes before counter appears, return null.
37 *
38 * @param job Job
39 * @param group Name of the counter group
40 * @return Name of the counter inside of the group, or null if job finishes
41 * before counter appears
42 */
43 public static String waitAndGetCounterNameFromGroup(Job job, String group) {
44 try {
45 while (job.getCounters().getGroup(group).size() == 0) {
46 if (job.isComplete()) {
47 return null;
48 }
49 Thread.sleep(SLEEP_MSECS);
50 }
51 return job.getCounters().getGroup(group).iterator().next().getName();
52 } catch (IOException | InterruptedException e) {
53 throw new IllegalStateException(
54 "waitAndGetCounterNameFromGroup: Exception occurred", e);
55 }
56 }
57 }