Java tutorial
/* * 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.openflamingo.mapreduce.util; import org.apache.hadoop.mapreduce.*; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.Collection; import java.util.HashMap; import java.util.Iterator; import java.util.Map; /** * Hadoop MapReduce Counter Utility. * * @author Edward KIM * @author Seo Ji Hye * @since 0.1 */ public class CounterUtils { /** * SLF4J Logging */ private static Logger logger = LoggerFactory.getLogger(CounterUtils.class); /** * Mapper? Counter ?. * * @param mapper Mapper * @param name Counter Name * @param context Mapper? Context */ public static void writerMapperCounter(Mapper mapper, String name, Mapper.Context context) { context.getCounter(mapper.getClass().getName(), name).increment(1); } /** * Reducer? Counter ?. * * @param reducer Reducer * @param name Counter Name * @param context Reducer? Context */ public static void writerReducerCounter(Reducer reducer, String name, Reducer.Context context) { context.getCounter(reducer.getClass().getName(), name).increment(1); } /** * Job? ?? Counter Map ? . * Key? <tt>GROUP_COUNTER</tt> ? Group Name? * <tt>CLEAN</tt>?, Counter <tt>VALID</tt>? Key * <tt>CLEAN_VALID</tt> ?. * * @param job Hadoop Job * @return Counter ? ? Map */ public static Map<String, String> getCounters(Job job) { Map<String, String> resultMap = new HashMap<String, String>(); try { Counters counters = job.getCounters(); Collection<String> groupNames = counters.getGroupNames(); Iterator<String> groupIterator = groupNames.iterator(); while (groupIterator.hasNext()) { String groupName = groupIterator.next(); CounterGroup group = counters.getGroup(groupName); Iterator<Counter> counterIterator = group.iterator(); while (counterIterator.hasNext()) { Counter counter = counterIterator.next(); logger.info("[{}] {} = {}", new Object[] { group.getName(), counter.getName(), counter.getValue() }); String realName = HadoopMetrics.getMetricName(group.getName() + "_" + counter.getName()); if (!StringUtils.isEmpty(realName)) { resultMap.put(realName, String.valueOf(counter.getValue())); } } } } catch (Exception ex) { } return resultMap; } }