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 */ 018 019 package org.apache.hadoop.mapred.lib.aggregate; 020 021 import java.io.IOException; 022 import java.util.ArrayList; 023 024 import org.apache.hadoop.classification.InterfaceAudience; 025 import org.apache.hadoop.classification.InterfaceStability; 026 import org.apache.hadoop.io.Text; 027 import org.apache.hadoop.io.Writable; 028 import org.apache.hadoop.io.WritableComparable; 029 import org.apache.hadoop.mapred.JobConf; 030 import org.apache.hadoop.mapred.Mapper; 031 import org.apache.hadoop.mapred.Reducer; 032 033 /** 034 * This abstract class implements some common functionalities of the 035 * the generic mapper, reducer and combiner classes of Aggregate. 036 */ 037 @InterfaceAudience.Public 038 @InterfaceStability.Stable 039 public abstract class ValueAggregatorJobBase<K1 extends WritableComparable, 040 V1 extends Writable> 041 implements Mapper<K1, V1, Text, Text>, Reducer<Text, Text, Text, Text> { 042 043 protected ArrayList<ValueAggregatorDescriptor> aggregatorDescriptorList = null; 044 045 public void configure(JobConf job) { 046 this.initializeMySpec(job); 047 this.logSpec(); 048 } 049 050 private static ValueAggregatorDescriptor getValueAggregatorDescriptor( 051 String spec, JobConf job) { 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, job); 059 } 060 return null; 061 } 062 063 private static ArrayList<ValueAggregatorDescriptor> getAggregatorDescriptors(JobConf job) { 064 String advn = "aggregator.descriptor"; 065 int num = job.getInt(advn + ".num", 0); 066 ArrayList<ValueAggregatorDescriptor> retv = new ArrayList<ValueAggregatorDescriptor>(num); 067 for (int i = 0; i < num; i++) { 068 String spec = job.get(advn + "." + i); 069 ValueAggregatorDescriptor ad = getValueAggregatorDescriptor(spec, job); 070 if (ad != null) { 071 retv.add(ad); 072 } 073 } 074 return retv; 075 } 076 077 private void initializeMySpec(JobConf job) { 078 this.aggregatorDescriptorList = getAggregatorDescriptors(job); 079 if (this.aggregatorDescriptorList.size() == 0) { 080 this.aggregatorDescriptorList 081 .add(new UserDefinedValueAggregatorDescriptor( 082 ValueAggregatorBaseDescriptor.class.getCanonicalName(), job)); 083 } 084 } 085 086 protected void logSpec() { 087 088 } 089 090 public void close() throws IOException { 091 } 092 }