ApplesToVectors.java

package mia.clustering.ch08;

import java.util.ArrayList;
import java.util.List;

import org.apache.hadoop.conf.Configuration;
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.mahout.math.DenseVector;
import org.apache.mahout.math.NamedVector;
import org.apache.mahout.math.VectorWritable;

public class ApplesToVectors {
  public static void main(String args[]) throws Exception {
    List<NamedVector> apples = new ArrayList<NamedVector>();
    
    NamedVector apple;
    apple = new NamedVector(                    
        new DenseVector(new double[] {0.11, 510, 1}),
        "Small round green apple");
    apples.add(apple);
    apple = new NamedVector(
      new DenseVector(new double[] {0.23, 650, 3}),
        "Large oval red apple");
    apples.add(apple);
    apple = new NamedVector(
      new DenseVector(new double[] {0.09, 630, 1}),
        "Small elongated red apple");
    apples.add(apple);
    apple = new NamedVector(
      new DenseVector(new double[] {0.25, 590, 3}),
        "Large round yellow apple");
    apples.add(apple);
    apple = new NamedVector(
      new DenseVector(new double[] {0.18, 520, 2}),
        "Medium oval green apple");

    
    Configuration conf = new Configuration();
    FileSystem fs = FileSystem.get(conf);
    
    Path path = new Path("appledata/apples");
    SequenceFile.Writer writer = new SequenceFile.Writer(fs, conf,
        path, Text.class, VectorWritable.class);
    VectorWritable vec = new VectorWritable();
    for (NamedVector vector : apples) {
      vec.set(vector);
      writer.append(new Text(vector.getName()), vec);
    }
    writer.close();
    
    SequenceFile.Reader reader = new SequenceFile.Reader(fs,
        new Path("appledata/apples"), conf);
    
    Text key = new Text();
    VectorWritable value = new VectorWritable();
    while (reader.next(key, value)) {
      System.out.println(key.toString() + " " + value.get().asFormatString());
    }
    reader.close();
  }
}