/**
* 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.apache.mahout.fpm.pfpgrowth;
import java.io.IOException;
import java.util.List;
import com.google.common.collect.Lists;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.mahout.common.Pair;
import org.apache.mahout.fpm.pfpgrowth.convertors.string.TopKStringPatterns;
/**
*
* outputs the pattern for each item in the pattern, so that reducer can group them
* and select the top K frequent patterns
*
*/
public class AggregatorMapper extends Mapper<Text,TopKStringPatterns,Text,TopKStringPatterns> {
@Override
protected void map(Text key, TopKStringPatterns values, Context context) throws IOException,
InterruptedException {
for (Pair<List<String>,Long> pattern : values.getPatterns()) {
for (String item : pattern.getFirst()) {
List<Pair<List<String>,Long>> patternSingularList = Lists.newArrayList();
patternSingularList.add(pattern);
context.setStatus("Aggregator Mapper:Grouping Patterns for " + item);
context.write(new Text(item), new TopKStringPatterns(patternSingularList));
}
}
}
}