/**
* 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;
}
}