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.mapred.lib.aggregate;
020
021import java.util.Map.Entry;
022
023import org.apache.hadoop.classification.InterfaceAudience;
024import org.apache.hadoop.classification.InterfaceStability;
025import org.apache.hadoop.io.Text;
026import org.apache.hadoop.mapred.JobConf;
027
028/** 
029 * This class implements the common functionalities of 
030 * the subclasses of ValueAggregatorDescriptor class.
031 */
032@InterfaceAudience.Public
033@InterfaceStability.Stable
034public class ValueAggregatorBaseDescriptor extends org.apache.hadoop.mapreduce.
035    lib.aggregate.ValueAggregatorBaseDescriptor 
036    implements ValueAggregatorDescriptor {
037
038  static public final String UNIQ_VALUE_COUNT = org.apache.hadoop.mapreduce.
039    lib.aggregate.ValueAggregatorBaseDescriptor.UNIQ_VALUE_COUNT;
040
041  static public final String LONG_VALUE_SUM = org.apache.hadoop.mapreduce.
042    lib.aggregate.ValueAggregatorBaseDescriptor.LONG_VALUE_SUM;
043
044  static public final String DOUBLE_VALUE_SUM = org.apache.hadoop.mapreduce.
045    lib.aggregate.ValueAggregatorBaseDescriptor.DOUBLE_VALUE_SUM;
046
047  static public final String VALUE_HISTOGRAM = org.apache.hadoop.mapreduce.
048    lib.aggregate.ValueAggregatorBaseDescriptor.VALUE_HISTOGRAM;
049  
050  static public final String LONG_VALUE_MAX = org.apache.hadoop.mapreduce.
051    lib.aggregate.ValueAggregatorBaseDescriptor.LONG_VALUE_MAX;
052  
053  static public final String LONG_VALUE_MIN = org.apache.hadoop.mapreduce.
054    lib.aggregate.ValueAggregatorBaseDescriptor.LONG_VALUE_MIN;
055  
056  static public final String STRING_VALUE_MAX = org.apache.hadoop.mapreduce.
057    lib.aggregate.ValueAggregatorBaseDescriptor.STRING_VALUE_MAX;
058  
059  static public final String STRING_VALUE_MIN = org.apache.hadoop.mapreduce.
060    lib.aggregate.ValueAggregatorBaseDescriptor.STRING_VALUE_MIN;
061
062  private static long maxNumItems = Long.MAX_VALUE; 
063  
064 /**
065   * 
066   * @param type the aggregation type
067   * @param id the aggregation id
068   * @param val the val associated with the id to be aggregated
069   * @return an Entry whose key is the aggregation id prefixed with 
070   * the aggregation type.
071   */
072  public static Entry<Text, Text> generateEntry(String type, String id, Text val) {
073    return org.apache.hadoop.mapreduce.lib.aggregate.
074      ValueAggregatorBaseDescriptor.generateEntry(type, id, val);
075  }
076
077  /**
078   * 
079   * @param type the aggregation type
080   * @return a value aggregator of the given type.
081   */
082  static public ValueAggregator generateValueAggregator(String type) {
083    ValueAggregator retv = null;
084    if (type.compareToIgnoreCase(LONG_VALUE_SUM) == 0) {
085      retv = new LongValueSum();
086    } if (type.compareToIgnoreCase(LONG_VALUE_MAX) == 0) {
087      retv = new LongValueMax();
088    } else if (type.compareToIgnoreCase(LONG_VALUE_MIN) == 0) {
089      retv = new LongValueMin();
090    } else if (type.compareToIgnoreCase(STRING_VALUE_MAX) == 0) {
091      retv = new StringValueMax();
092    } else if (type.compareToIgnoreCase(STRING_VALUE_MIN) == 0) {
093      retv = new StringValueMin();
094    } else if (type.compareToIgnoreCase(DOUBLE_VALUE_SUM) == 0) {
095      retv = new DoubleValueSum();
096    } else if (type.compareToIgnoreCase(UNIQ_VALUE_COUNT) == 0) {
097      retv = new UniqValueCount(maxNumItems);
098    } else if (type.compareToIgnoreCase(VALUE_HISTOGRAM) == 0) {
099      retv = new ValueHistogram();
100    }
101    return retv;
102  }
103
104  /**
105   * get the input file name.
106   * 
107   * @param job a job configuration object
108   */
109  public void configure(JobConf job) {
110    super.configure(job);
111    maxNumItems = job.getLong("aggregate.max.num.unique.values",
112                              Long.MAX_VALUE);
113  }
114}