made OtelTraceState and RandomGenerator package private and moved the…

…m to samplers package

consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/ConsistentAlwaysOffSampler.java

@@ -5,7 +5,6 @@
 
 package io.opentelemetry.contrib.samplers;
 
-import io.opentelemetry.contrib.state.OtelTraceState;
 import javax.annotation.concurrent.Immutable;
 
 @Immutable

consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/ConsistentComposedAndSampler.java

@@ -7,7 +7,6 @@
 
 import static java.util.Objects.requireNonNull;
 
-import io.opentelemetry.contrib.state.OtelTraceState;
 import javax.annotation.concurrent.Immutable;
 
 /**

consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/ConsistentComposedOrSampler.java

@@ -7,7 +7,6 @@
 
 import static java.util.Objects.requireNonNull;
 
-import io.opentelemetry.contrib.state.OtelTraceState;
 import javax.annotation.concurrent.Immutable;
 
 /**

consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/ConsistentParentBasedSampler.java

@@ -7,7 +7,6 @@
 
 import static java.util.Objects.requireNonNull;
 
-import io.opentelemetry.contrib.util.RandomGenerator;
 import javax.annotation.concurrent.Immutable;
 
 /**

consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/ConsistentProbabilityBasedSampler.java

@@ -5,7 +5,6 @@
 
 package io.opentelemetry.contrib.samplers;
 
-import io.opentelemetry.contrib.util.RandomGenerator;
 import javax.annotation.concurrent.Immutable;
 
 /** A consistent sampler that samples with a fixed probability. */

consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/ConsistentRateLimitingSampler.java

@@ -7,7 +7,6 @@
 
 import static java.util.Objects.requireNonNull;
 
-import io.opentelemetry.contrib.util.RandomGenerator;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.LongSupplier;

consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/ConsistentSampler.java

@@ -13,8 +13,6 @@
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.api.trace.TraceState;
 import io.opentelemetry.context.Context;
-import io.opentelemetry.contrib.state.OtelTraceState;
-import io.opentelemetry.contrib.util.RandomGenerator;
 import io.opentelemetry.sdk.trace.data.LinkData;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 import io.opentelemetry.sdk.trace.samplers.SamplingDecision;
@@ -60,7 +58,7 @@ public static final ConsistentSampler probabilityBased(double samplingProbabilit
    * @param randomGenerator a random generator
    * @return a sampler
    */
-  public static final ConsistentSampler probabilityBased(
+  static final ConsistentSampler probabilityBased(
       double samplingProbability, RandomGenerator randomGenerator) {
     return new ConsistentProbabilityBasedSampler(samplingProbability, randomGenerator);
   }
@@ -82,7 +80,7 @@ public static final ConsistentSampler parentBased(ConsistentSampler rootSampler)
    * @param rootSampler the root sampler
    * @param randomGenerator a random generator
    */
-  public static final ConsistentSampler parentBased(
+  static final ConsistentSampler parentBased(
       ConsistentSampler rootSampler, RandomGenerator randomGenerator) {
     return new ConsistentParentBasedSampler(rootSampler, randomGenerator);
   }
@@ -110,7 +108,7 @@ public static final ConsistentSampler rateLimited(
    * @param randomGenerator a random generator
    * @param nanoTimeSupplier a supplier for the current nano time
    */
-  public static final ConsistentSampler rateLimited(
+  static final ConsistentSampler rateLimited(
       double targetSpansPerSecondLimit,
       double adaptationTimeSeconds,
       RandomGenerator randomGenerator,

consistent-sampling/src/main/java/io/opentelemetry/contrib/state/OtelTraceState.java → consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/OtelTraceState.java

@@ -3,14 +3,14 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.contrib.state;
+package io.opentelemetry.contrib.samplers;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import javax.annotation.Nullable;
 
-public final class OtelTraceState {
+final class OtelTraceState {
 
   public static final String TRACE_STATE_KEY = "ot";
 

consistent-sampling/src/main/java/io/opentelemetry/contrib/util/RandomGenerator.java → consistent-sampling/src/main/java/io/opentelemetry/contrib/samplers/RandomGenerator.java

@@ -3,14 +3,14 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.contrib.util;
+package io.opentelemetry.contrib.samplers;
 
 import static java.util.Objects.requireNonNull;
 
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.function.LongSupplier;
 
-public final class RandomGenerator {
+final class RandomGenerator {
 
   private final LongSupplier threadSafeRandomLongSupplier;
 

consistent-sampling/src/test/java/io/opentelemetry/contrib/samplers/ConsistentProbabilityBasedSamplerTest.java

@@ -5,15 +5,13 @@
 
 package io.opentelemetry.contrib.samplers;
 
-import static io.opentelemetry.contrib.util.TestUtil.verifyObservedPvaluesUsingGtest;
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.api.trace.TraceState;
 import io.opentelemetry.context.Context;
-import io.opentelemetry.contrib.state.OtelTraceState;
-import io.opentelemetry.contrib.util.RandomGenerator;
 import io.opentelemetry.sdk.trace.data.LinkData;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 import io.opentelemetry.sdk.trace.samplers.SamplingDecision;
@@ -23,6 +21,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.SplittableRandom;
+import org.hipparchus.stat.inference.GTest;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
@@ -87,4 +86,64 @@ public void test() {
     test(random, 0.13);
     test(random, 0.05);
   }
+
+  private static void verifyObservedPvaluesUsingGtest(
+      long originalNumberOfSpans, Map<Integer, Long> observedPvalues, double samplingProbability) {
+
+    Object notSampled =
+        new Object() {
+          @Override
+          public String toString() {
+            return "NOT SAMPLED";
+          }
+        };
+
+    Map<Object, Double> expectedProbabilities = new HashMap<>();
+    if (samplingProbability >= 1.) {
+      expectedProbabilities.put(0, 1.);
+    } else if (samplingProbability <= 0.) {
+      expectedProbabilities.put(notSampled, 1.);
+    } else {
+      int exponent = 0;
+      while (true) {
+        if (Math.pow(0.5, exponent + 1) < samplingProbability
+            && Math.pow(0.5, exponent) >= samplingProbability) {
+          break;
+        }
+        exponent += 1;
+      }
+      if (samplingProbability == Math.pow(0.5, exponent)) {
+        expectedProbabilities.put(notSampled, 1 - samplingProbability);
+        expectedProbabilities.put(exponent, samplingProbability);
+      } else {
+        expectedProbabilities.put(notSampled, 1 - samplingProbability);
+        expectedProbabilities.put(exponent, 2 * samplingProbability - Math.pow(0.5, exponent));
+        expectedProbabilities.put(exponent + 1, Math.pow(0.5, exponent) - samplingProbability);
+      }
+    }
+
+    Map<Object, Long> extendedObservedAdjustedCounts = new HashMap<>(observedPvalues);
+    long numberOfSpansNotSampled =
+        originalNumberOfSpans - observedPvalues.values().stream().mapToLong(i -> i).sum();
+    if (numberOfSpansNotSampled > 0) {
+      extendedObservedAdjustedCounts.put(notSampled, numberOfSpansNotSampled);
+    }
+
+    double[] expectedValues = new double[expectedProbabilities.size()];
+    long[] observedValues = new long[expectedProbabilities.size()];
+
+    int counter = 0;
+    for (Object key : expectedProbabilities.keySet()) {
+      observedValues[counter] = extendedObservedAdjustedCounts.getOrDefault(key, 0L);
+      double p = expectedProbabilities.get(key);
+      expectedValues[counter] = p * originalNumberOfSpans;
+      counter += 1;
+    }
+
+    if (expectedProbabilities.size() > 1) {
+      assertThat(new GTest().gTest(expectedValues, observedValues)).isGreaterThan(0.01);
+    } else {
+      assertThat((double) observedValues[0]).isEqualTo(expectedValues[0]);
+    }
+  }
 }

consistent-sampling/src/test/java/io/opentelemetry/contrib/samplers/ConsistentRateLimitingSamplerTest.java

@@ -10,7 +10,6 @@
 import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.context.Context;
-import io.opentelemetry.contrib.util.RandomGenerator;
 import io.opentelemetry.sdk.trace.data.LinkData;
 import io.opentelemetry.sdk.trace.samplers.SamplingDecision;
 import io.opentelemetry.sdk.trace.samplers.SamplingResult;

consistent-sampling/src/test/java/io/opentelemetry/contrib/samplers/ConsistentSamplerTest.java

@@ -9,7 +9,6 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
-import io.opentelemetry.contrib.state.OtelTraceState;
 import java.util.SplittableRandom;
 import org.junit.jupiter.api.Test;
 

consistent-sampling/src/test/java/io/opentelemetry/contrib/state/OtelTraceStateTest.java → consistent-sampling/src/test/java/io/opentelemetry/contrib/samplers/OtelTraceStateTest.java

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.contrib.state;
+package io.opentelemetry.contrib.samplers;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;