org.apache.mahout.classifier.df.mapreduce.inmem.InMemBuilder.java Source code

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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.classifier.df.mapreduce.inmem;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
import org.apache.mahout.classifier.df.DFUtils;
import org.apache.mahout.classifier.df.DecisionForest;
import org.apache.mahout.classifier.df.builder.TreeBuilder;
import org.apache.mahout.classifier.df.mapreduce.Builder;
import org.apache.mahout.classifier.df.mapreduce.MapredOutput;
import org.apache.mahout.classifier.df.node.Node;
import org.apache.mahout.common.Pair;
import org.apache.mahout.common.iterator.sequencefile.SequenceFileIterable;

/**
 * MapReduce implementation where each mapper loads a full copy of the data in-memory. The forest trees are
 * splitted across all the mappers
 */
@Deprecated
public class InMemBuilder extends Builder {

    public InMemBuilder(TreeBuilder treeBuilder, Path dataPath, Path datasetPath, Long seed, Configuration conf) {
        super(treeBuilder, dataPath, datasetPath, seed, conf);
    }

    public InMemBuilder(TreeBuilder treeBuilder, Path dataPath, Path datasetPath) {
        this(treeBuilder, dataPath, datasetPath, null, new Configuration());
    }

    @Override
    protected void configureJob(Job job) throws IOException {
        Configuration conf = job.getConfiguration();

        job.setJarByClass(InMemBuilder.class);

        FileOutputFormat.setOutputPath(job, getOutputPath(conf));

        // put the data in the DistributedCache
        DistributedCache.addCacheFile(getDataPath().toUri(), conf);

        job.setOutputKeyClass(IntWritable.class);
        job.setOutputValueClass(MapredOutput.class);

        job.setMapperClass(InMemMapper.class);
        job.setNumReduceTasks(0); // no reducers

        job.setInputFormatClass(InMemInputFormat.class);
        job.setOutputFormatClass(SequenceFileOutputFormat.class);

    }

    @Override
    protected DecisionForest parseOutput(Job job) throws IOException {
        Configuration conf = job.getConfiguration();

        Map<Integer, MapredOutput> output = new HashMap<>();

        Path outputPath = getOutputPath(conf);
        FileSystem fs = outputPath.getFileSystem(conf);

        Path[] outfiles = DFUtils.listOutputFiles(fs, outputPath);

        // import the InMemOutputs
        for (Path path : outfiles) {
            for (Pair<IntWritable, MapredOutput> record : new SequenceFileIterable<IntWritable, MapredOutput>(path,
                    conf)) {
                output.put(record.getFirst().get(), record.getSecond());
            }
        }

        return processOutput(output);
    }

    /**
     * Process the output, extracting the trees
     */
    private static DecisionForest processOutput(Map<Integer, MapredOutput> output) {
        List<Node> trees = new ArrayList<>();

        for (Map.Entry<Integer, MapredOutput> entry : output.entrySet()) {
            MapredOutput value = entry.getValue();
            trees.add(value.getTree());
        }

        return new DecisionForest(trees);
    }
}