/**
* 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.clustering.canopy;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.mahout.matrix.AbstractVector;
import org.apache.mahout.matrix.Vector;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
public class ClusterMapper extends MapReduceBase implements
Mapper<WritableComparable<?>, Text, Text, Text> {
private List<Canopy> canopies;
@Override
public void map(WritableComparable<?> key, Text values,
OutputCollector<Text, Text> output, Reporter reporter) throws IOException {
Vector point = AbstractVector.decodeVector(values.toString());
Canopy.emitPointToExistingCanopies(point, canopies, values, output);
}
/**
* Configure the mapper by providing its canopies. Used by unit tests.
*
* @param canopies a List<Canopy>
*/
public void config(List<Canopy> canopies) {
this.canopies = canopies;
}
@Override
public void configure(JobConf job) {
super.configure(job);
Canopy.configure(job);
String canopyPath = job.get(Canopy.CANOPY_PATH_KEY);
canopies = new ArrayList<Canopy>();
try {
FileSystem fs = FileSystem.get(job);
Path path = new Path(canopyPath + "/part-00000");
SequenceFile.Reader reader = new SequenceFile.Reader(fs, path, job);
try {
Text key = new Text();
Text value = new Text();
while (reader.next(key, value)) {
Canopy canopy = Canopy.decodeCanopy(value.toString());
canopies.add(canopy);
}
} finally {
reader.close();
}
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}