Github user justinleet commented on a diff in the pull request:
https://github.com/apache/metron/pull/958#discussion_r173936212
--- Diff:
metron-contrib/metron-performance/src/main/java/org/apache/metron/performance/sampler/BiasedSampler.java
---
@@ -0,0 +1,95 @@
+/**
+ * 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.metron.performance.sampler;
+
+import com.google.common.base.Splitter;
+import com.google.common.collect.Iterables;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.AbstractMap;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.TreeMap;
+
+public class BiasedSampler implements Sampler {
+ TreeMap<Double, Map.Entry<Integer, Integer>> discreteDistribution;
+ public BiasedSampler(List<Map.Entry<Integer, Integer>>
discreteDistribution, int max) {
+ this.discreteDistribution = createDistribution(discreteDistribution,
max);
+ }
+
+ public static List<Map.Entry<Integer, Integer>> readDistribution(File
distrFile) throws IOException {
+ List<Map.Entry<Integer, Integer>> ret = new ArrayList<>();
+ System.out.println("Using biased sampler with the following biases:");
+ try(BufferedReader br = new BufferedReader(new FileReader(distrFile)))
{
+ int sumLeft = 0;
+ int sumRight = 0;
+ for(String line = null;(line = br.readLine()) != null;) {
+ if(line.startsWith("#")) {
+ continue;
+ }
+ Iterable<String> it = Splitter.on(",").split(line.trim());
+ int left = Integer.parseInt(Iterables.getFirst(it, null));
+ int right = Integer.parseInt(Iterables.getLast(it, null));
+ System.out.println("\t" + left + "% of templates will comprise
roughly " + right + "% of sample output");
+ ret.add(new AbstractMap.SimpleEntry<>(left, right));
+ sumLeft += left;
+ sumRight += right;
+ }
+ if(sumLeft > 100 || sumRight > 100 ) {
+ throw new IllegalStateException("Neither columns must sum to
beyond 100. " +
+ "The first column is the % of templates. " +
+ "The second column is the % of the sample that % of
template occupies.");
+ }
+ else if(sumLeft < 100 && sumRight < 100) {
+ int left = 100 - sumLeft;
+ int right = 100 - sumRight;
+ System.out.println("\t" + left + "% of templates will comprise
roughly " + right + "% of sample output");
+ ret.add(new AbstractMap.SimpleEntry<>(left, right));
+ }
+ return ret;
+ }
+ }
+
+ private static TreeMap<Double, Map.Entry<Integer, Integer>>
+ createDistribution(List<Map.Entry<Integer, Integer>>
discreteDistribution, int max) {
+ TreeMap<Double, Map.Entry<Integer, Integer>> ret = new TreeMap<>();
+ int from = 0;
+ double weight = 0.0d;
+ for(Map.Entry<Integer, Integer> kv : discreteDistribution) {
+ double pctVals = kv.getKey()/100.0;
+ int to = from + (int)(max*pctVals);
+ double pctWeight = kv.getValue()/100.0;
+ ret.put(weight, new AbstractMap.SimpleEntry<>(from, to));
+ weight += pctWeight;
+ from = to;
+ }
+ return ret;
+ }
+
+ @Override
+ public int sample(Random rng, int limit) {
+ double weight = rng.nextDouble();
+ Map.Entry<Integer, Integer> range =
discreteDistribution.floorEntry(weight).getValue();
+ return rng.nextInt(range.getValue() - range.getKey()) + range.getKey();
--- End diff --
Jerks like me who provide negatives or zeroes cause ugly exceptions to
start showing up. because the nextInt doesn't get happy values.
---
