org.apache.mahout.clustering.conversion.InputMapper.java Source code

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Here is the source code for org.apache.mahout.clustering.conversion.InputMapper.java

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/**
 * 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.conversion;

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.Collection;
import java.util.regex.Pattern;

import com.google.common.collect.Lists;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.VectorWritable;

public class InputMapper extends Mapper<LongWritable, Text, Text, VectorWritable> {

    private static final Pattern SPACE = Pattern.compile(" ");

    private Constructor<?> constructor;

    @Override
    protected void map(LongWritable key, Text values, Context context) throws IOException, InterruptedException {

        String[] numbers = SPACE.split(values.toString());
        // sometimes there are multiple separator spaces
        Collection<Double> doubles = Lists.newArrayList();
        for (String value : numbers) {
            if (!value.isEmpty()) {
                doubles.add(Double.valueOf(value));
            }
        }
        // ignore empty lines in data file
        if (!doubles.isEmpty()) {
            try {
                Vector result = (Vector) constructor.newInstance(doubles.size());
                int index = 0;
                for (Double d : doubles) {
                    result.set(index++, d);
                }
                VectorWritable vectorWritable = new VectorWritable(result);
                context.write(new Text(String.valueOf(index)), vectorWritable);

            } catch (InstantiationException e) {
                throw new IllegalStateException(e);
            } catch (IllegalAccessException e) {
                throw new IllegalStateException(e);
            } catch (InvocationTargetException e) {
                throw new IllegalStateException(e);
            }
        }
    }

    @Override
    protected void setup(Context context) throws IOException, InterruptedException {
        super.setup(context);
        Configuration conf = context.getConfiguration();
        String vectorImplClassName = conf.get("vector.implementation.class.name");
        try {
            Class<? extends Vector> outputClass = conf.getClassByName(vectorImplClassName).asSubclass(Vector.class);
            constructor = outputClass.getConstructor(int.class);
        } catch (NoSuchMethodException e) {
            throw new IllegalStateException(e);
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException(e);
        }
    }

}