org.apache.mahout.common.distance.WeightedDistanceMeasure.java Source code

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Here is the source code for org.apache.mahout.common.distance.WeightedDistanceMeasure.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.common.distance;

import java.io.DataInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Collection;
import java.util.List;

import com.google.common.collect.Lists;
import com.google.common.io.Closeables;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.mahout.common.ClassUtils;
import org.apache.mahout.common.parameters.ClassParameter;
import org.apache.mahout.common.parameters.Parameter;
import org.apache.mahout.common.parameters.PathParameter;
import org.apache.mahout.math.DenseVector;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.VectorWritable;

/** Abstract implementation of DistanceMeasure with support for weights. */
public abstract class WeightedDistanceMeasure implements DistanceMeasure {

    private List<Parameter<?>> parameters;
    private Parameter<Path> weightsFile;
    private ClassParameter vectorClass;
    private Vector weights;

    @Override
    public void createParameters(String prefix, Configuration jobConf) {
        parameters = Lists.newArrayList();
        weightsFile = new PathParameter(prefix, "weightsFile", jobConf, null,
                "Path on DFS to a file containing the weights.");
        parameters.add(weightsFile);
        vectorClass = new ClassParameter(prefix, "vectorClass", jobConf, DenseVector.class,
                "Class<Vector> file specified in parameter weightsFile has been serialized with.");
        parameters.add(vectorClass);
    }

    @Override
    public Collection<Parameter<?>> getParameters() {
        return parameters;
    }

    @Override
    public void configure(Configuration jobConf) {
        if (parameters == null) {
            ParameteredGeneralizations.configureParameters(this, jobConf);
        }
        try {
            if (weightsFile.get() != null) {
                FileSystem fs = FileSystem.get(weightsFile.get().toUri(), jobConf);
                VectorWritable weights = ClassUtils
                        .instantiateAs((Class<? extends VectorWritable>) vectorClass.get(), VectorWritable.class);
                if (!fs.exists(weightsFile.get())) {
                    throw new FileNotFoundException(weightsFile.get().toString());
                }
                DataInputStream in = fs.open(weightsFile.get());
                try {
                    weights.readFields(in);
                } finally {
                    Closeables.close(in, true);
                }
                this.weights = weights.get();
            }
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }

    public Vector getWeights() {
        return weights;
    }

    public void setWeights(Vector weights) {
        this.weights = weights;
    }

}