io.virtdata.random.RandomLineToInt Maven / Gradle / Ivy
package io.virtdata.random;
import io.virtdata.annotations.DeprecatedFunction;
import io.virtdata.util.VirtDataResources;
import org.apache.commons.math3.distribution.IntegerDistribution;
import org.apache.commons.math3.distribution.UniformIntegerDistribution;
import org.apache.commons.math3.random.MersenneTwister;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
import java.util.function.LongToIntFunction;
@DeprecatedFunction("random mappers are not deterministic. They will be replaced with hash-based functions.")
public class RandomLineToInt implements LongToIntFunction {
private final static Logger logger = LoggerFactory.getLogger(RandomLineToInt.class);
private final List lines;
private final MersenneTwister rng;
private final IntegerDistribution itemDistribution;
private final String filename;
public RandomLineToInt(String filename) {
this(filename, System.nanoTime());
}
public RandomLineToInt(String filename, long seed) {
this.filename = filename;
this.lines = VirtDataResources.readDataFileLines(filename);
this.rng = new MersenneTwister(seed);
this.itemDistribution= new UniformIntegerDistribution(rng, 0, lines.size()-2);
}
public String toString() {
return getClass().getSimpleName() + ":" + filename;
}
@Override
public int applyAsInt(long value) {
int itemIdx = itemDistribution.sample();
String item = lines.get(itemIdx);
return Integer.valueOf(item);
}
}