001/** 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 019package org.apache.hadoop.mapreduce.lib.aggregate; 020 021import java.util.ArrayList; 022 023import org.apache.hadoop.classification.InterfaceAudience; 024import org.apache.hadoop.classification.InterfaceStability; 025import org.apache.hadoop.conf.Configuration; 026import org.apache.hadoop.io.Writable; 027import org.apache.hadoop.io.WritableComparable; 028 029/** 030 * This abstract class implements some common functionalities of the 031 * the generic mapper, reducer and combiner classes of Aggregate. 032 */ 033@InterfaceAudience.Public 034@InterfaceStability.Stable 035public class ValueAggregatorJobBase<K1 extends WritableComparable<?>, 036 V1 extends Writable> 037{ 038 public static final String DESCRIPTOR = "mapreduce.aggregate.descriptor"; 039 public static final String DESCRIPTOR_NUM = 040 "mapreduce.aggregate.descriptor.num"; 041 public static final String USER_JAR = "mapreduce.aggregate.user.jar.file"; 042 043 protected static ArrayList<ValueAggregatorDescriptor> aggregatorDescriptorList = null; 044 045 public static void setup(Configuration job) { 046 initializeMySpec(job); 047 logSpec(); 048 } 049 050 protected static ValueAggregatorDescriptor getValueAggregatorDescriptor( 051 String spec, Configuration conf) { 052 if (spec == null) 053 return null; 054 String[] segments = spec.split(",", -1); 055 String type = segments[0]; 056 if (type.compareToIgnoreCase("UserDefined") == 0) { 057 String className = segments[1]; 058 return new UserDefinedValueAggregatorDescriptor(className, conf); 059 } 060 return null; 061 } 062 063 protected static ArrayList<ValueAggregatorDescriptor> getAggregatorDescriptors( 064 Configuration conf) { 065 int num = conf.getInt(DESCRIPTOR_NUM, 0); 066 ArrayList<ValueAggregatorDescriptor> retv = 067 new ArrayList<ValueAggregatorDescriptor>(num); 068 for (int i = 0; i < num; i++) { 069 String spec = conf.get(DESCRIPTOR + "." + i); 070 ValueAggregatorDescriptor ad = getValueAggregatorDescriptor(spec, conf); 071 if (ad != null) { 072 retv.add(ad); 073 } 074 } 075 return retv; 076 } 077 078 private static void initializeMySpec(Configuration conf) { 079 aggregatorDescriptorList = getAggregatorDescriptors(conf); 080 if (aggregatorDescriptorList.size() == 0) { 081 aggregatorDescriptorList 082 .add(new UserDefinedValueAggregatorDescriptor( 083 ValueAggregatorBaseDescriptor.class.getCanonicalName(), conf)); 084 } 085 } 086 087 protected static void logSpec() { 088 } 089}