package com.mapr.synth.samplers;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.TextNode;
import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.io.Resources;
import org.apache.mahout.math.random.Multinomial;
import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;
/**
* Sample from a multinomial of strings.
*
* Tip of the hat to http://www.jimwegryn.com/Names/StreetNameGenerator.htm
*
* Thread safe for sampling
*/
public class StringSampler extends FieldSampler {
private AtomicReference<Multinomial<String>> distribution = new AtomicReference<>();
public StringSampler() {
}
protected void readDistribution(String resourceName) {
try {
if (distribution.compareAndSet(null, new Multinomial<String>())) {
Splitter onTab = Splitter.on("\t").trimResults();
for (String line : Resources.readLines(Resources.getResource(resourceName), Charsets.UTF_8)) {
if (!line.startsWith("#")) {
Iterator<String> parts = onTab.split(line).iterator();
String name = translate(parts.next());
double weight = Double.parseDouble(parts.next());
distribution.get().add(name, weight);
}
}
}
} catch (IOException e) {
throw new RuntimeException("Couldn't read built-in resource file", e);
}
}
public void setDist(Map<String, ?> dist) {
Preconditions.checkArgument(dist.size() > 0);
distribution.compareAndSet(null, new Multinomial<String>());
for (String key : dist.keySet()) {
distribution.get().add(key, Double.parseDouble(dist.get(key).toString()));
}
}
protected String translate(String s) {
return s;
}
@Override
public JsonNode sample() {
synchronized (this) {
return new TextNode(distribution.get().sample());
}
}
}