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; 022import java.util.Map.Entry; 023 024import org.apache.hadoop.classification.InterfaceAudience; 025import org.apache.hadoop.classification.InterfaceStability; 026import org.apache.hadoop.conf.Configuration; 027import org.apache.hadoop.io.Text; 028import org.apache.hadoop.mapreduce.MRJobConfig; 029 030/** 031 * This class implements the common functionalities of 032 * the subclasses of ValueAggregatorDescriptor class. 033 */ 034@InterfaceAudience.Public 035@InterfaceStability.Stable 036public class ValueAggregatorBaseDescriptor 037 implements ValueAggregatorDescriptor { 038 039 static public final String UNIQ_VALUE_COUNT = "UniqValueCount"; 040 041 static public final String LONG_VALUE_SUM = "LongValueSum"; 042 043 static public final String DOUBLE_VALUE_SUM = "DoubleValueSum"; 044 045 static public final String VALUE_HISTOGRAM = "ValueHistogram"; 046 047 static public final String LONG_VALUE_MAX = "LongValueMax"; 048 049 static public final String LONG_VALUE_MIN = "LongValueMin"; 050 051 static public final String STRING_VALUE_MAX = "StringValueMax"; 052 053 static public final String STRING_VALUE_MIN = "StringValueMin"; 054 055 public String inputFile = null; 056 057 private static class MyEntry implements Entry<Text, Text> { 058 Text key; 059 060 Text val; 061 062 public Text getKey() { 063 return key; 064 } 065 066 public Text getValue() { 067 return val; 068 } 069 070 public Text setValue(Text val) { 071 this.val = val; 072 return val; 073 } 074 075 public MyEntry(Text key, Text val) { 076 this.key = key; 077 this.val = val; 078 } 079 } 080 081 /** 082 * 083 * @param type the aggregation type 084 * @param id the aggregation id 085 * @param val the val associated with the id to be aggregated 086 * @return an Entry whose key is the aggregation id prefixed with 087 * the aggregation type. 088 */ 089 public static Entry<Text, Text> generateEntry(String type, 090 String id, Text val) { 091 Text key = new Text(type + TYPE_SEPARATOR + id); 092 return new MyEntry(key, val); 093 } 094 095 /** 096 * 097 * @param type the aggregation type 098 * @param uniqCount the limit in the number of unique values to keep, 099 * if type is UNIQ_VALUE_COUNT 100 * @return a value aggregator of the given type. 101 */ 102 static public ValueAggregator generateValueAggregator(String type, long uniqCount) { 103 if (type.compareToIgnoreCase(LONG_VALUE_SUM) == 0) { 104 return new LongValueSum(); 105 } if (type.compareToIgnoreCase(LONG_VALUE_MAX) == 0) { 106 return new LongValueMax(); 107 } else if (type.compareToIgnoreCase(LONG_VALUE_MIN) == 0) { 108 return new LongValueMin(); 109 } else if (type.compareToIgnoreCase(STRING_VALUE_MAX) == 0) { 110 return new StringValueMax(); 111 } else if (type.compareToIgnoreCase(STRING_VALUE_MIN) == 0) { 112 return new StringValueMin(); 113 } else if (type.compareToIgnoreCase(DOUBLE_VALUE_SUM) == 0) { 114 return new DoubleValueSum(); 115 } else if (type.compareToIgnoreCase(UNIQ_VALUE_COUNT) == 0) { 116 return new UniqValueCount(uniqCount); 117 } else if (type.compareToIgnoreCase(VALUE_HISTOGRAM) == 0) { 118 return new ValueHistogram(); 119 } 120 return null; 121 } 122 123 /** 124 * Generate 1 or 2 aggregation-id/value pairs for the given key/value pair. 125 * The first id will be of type LONG_VALUE_SUM, with "record_count" as 126 * its aggregation id. If the input is a file split, 127 * the second id of the same type will be generated too, with the file name 128 * as its aggregation id. This achieves the behavior of counting the total 129 * number of records in the input data, and the number of records 130 * in each input file. 131 * 132 * @param key 133 * input key 134 * @param val 135 * input value 136 * @return a list of aggregation id/value pairs. An aggregation id encodes an 137 * aggregation type which is used to guide the way to aggregate the 138 * value in the reduce/combiner phrase of an Aggregate based job. 139 */ 140 public ArrayList<Entry<Text, Text>> generateKeyValPairs(Object key, 141 Object val) { 142 ArrayList<Entry<Text, Text>> retv = new ArrayList<Entry<Text, Text>>(); 143 String countType = LONG_VALUE_SUM; 144 String id = "record_count"; 145 Entry<Text, Text> e = generateEntry(countType, id, ONE); 146 if (e != null) { 147 retv.add(e); 148 } 149 if (this.inputFile != null) { 150 e = generateEntry(countType, this.inputFile, ONE); 151 if (e != null) { 152 retv.add(e); 153 } 154 } 155 return retv; 156 } 157 158 /** 159 * get the input file name. 160 * 161 * @param conf a configuration object 162 */ 163 public void configure(Configuration conf) { 164 this.inputFile = conf.get(MRJobConfig.MAP_INPUT_FILE); 165 } 166}