CSVEncoderFastLine.java

/*
 * Source code for Listing 16.3
 * 
 */
package mia.classifier.ch16.samples;

import java.io.File;
import java.io.IOException;
import java.nio.ByteBuffer;

import org.apache.commons.io.FileUtils;
import org.apache.mahout.math.DenseVector;
import org.apache.mahout.math.Vector;
import org.apache.mahout.vectorizer.encoders.ConstantValueEncoder;
import org.apache.mahout.vectorizer.encoders.FeatureVectorEncoder;

public class CSVEncoderFastLine {
	private static final int FIELDS = 10;

	public static void main(String[] args) throws IOException {
		FeatureVectorEncoder[] encoder = new FeatureVectorEncoder[FIELDS];
		for (int i = 0; i < FIELDS; i++) {
			encoder[i] = new ConstantValueEncoder("v" + i);
		}
		long t0 = System.currentTimeMillis();
		Vector v = new DenseVector(1000);
		ByteBuffer buf = ByteBuffer.wrap(FileUtils
				.readFileToByteArray(new File(args[1])));
		FastLine line = FastLine.read(buf);
		while (line != null) {
			v.assign(0);
			for (int i = 0; i < FIELDS; i++) {
				encoder[i].addToVector((byte[]) null, line.getDouble(i), v);
			}
			line = FastLine.read(buf);
		}
		System.out.printf("\nElapsed time = %.3f s\n",
				(System.currentTimeMillis() - t0) / 1000.0);
	}

}