Add Base2 prefix to internal exponential histogram classes (#5179)

Author: jack-berg

sdk-extensions/incubator/src/test/java/io/opentelemetry/sdk/extension/incubator/metric/viewconfig/ViewConfigTest.java

@@ -21,8 +21,8 @@
 import io.opentelemetry.sdk.metrics.SdkMeterProviderBuilder;
 import io.opentelemetry.sdk.metrics.View;
 import io.opentelemetry.sdk.metrics.internal.view.AttributesProcessor;
+import io.opentelemetry.sdk.metrics.internal.view.Base2ExponentialHistogramAggregation;
 import io.opentelemetry.sdk.metrics.internal.view.ExplicitBucketHistogramAggregation;
-import io.opentelemetry.sdk.metrics.internal.view.ExponentialHistogramAggregation;
 import io.opentelemetry.sdk.metrics.internal.view.RegisteredView;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
@@ -230,7 +230,7 @@ void toAggregation_GoodConfig() {
     assertThat(
             ViewConfig.toAggregation(
                 "base2_exponential_bucket_histogram", ImmutableMap.of("max_buckets", 20)))
-        .isInstanceOf(ExponentialHistogramAggregation.class)
+        .isInstanceOf(Base2ExponentialHistogramAggregation.class)
         .extracting("maxBuckets", as(InstanceOfAssertFactories.INTEGER))
         .isEqualTo(20);
   }

sdk/metrics/src/jmh/java/io/opentelemetry/sdk/metrics/internal/aggregator/ExponentialHistogramIndexerBenchmark.java

@@ -36,7 +36,7 @@ public static class ThreadState {
 
     private double[] values;
     private final AtomicLong valueIndex = new AtomicLong();
-    private ExponentialHistogramIndexer indexer;
+    private Base2ExponentialHistogramIndexer indexer;
 
     @Setup(Level.Trial)
     public final void setup() {
@@ -46,7 +46,7 @@ public final void setup() {
       for (int i = 0; i < numValues; i++) {
         values[i] = random.nextDouble() * 1000;
       }
-      indexer = ExponentialHistogramIndexer.get(scale);
+      indexer = Base2ExponentialHistogramIndexer.get(scale);
     }
 
     public void compute() {

sdk/metrics/src/jmh/java/io/opentelemetry/sdk/metrics/internal/aggregator/HistogramAggregationParam.java

@@ -21,9 +21,9 @@ public enum HistogramAggregationParam {
           ExplicitBucketHistogramUtils.createBoundaryArray(Collections.emptyList()),
           ExemplarReservoir::doubleNoSamples)),
   EXPONENTIAL_SMALL_CIRCULAR_BUFFER(
-      new DoubleExponentialHistogramAggregator(ExemplarReservoir::doubleNoSamples, 20, 0)),
+      new DoubleBase2ExponentialHistogramAggregator(ExemplarReservoir::doubleNoSamples, 20, 0)),
   EXPONENTIAL_CIRCULAR_BUFFER(
-      new DoubleExponentialHistogramAggregator(ExemplarReservoir::doubleNoSamples, 160, 0));
+      new DoubleBase2ExponentialHistogramAggregator(ExemplarReservoir::doubleNoSamples, 160, 0));
 
   private final Aggregator<?, ?> aggregator;
 

sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/Aggregation.java

@@ -6,10 +6,10 @@
 package io.opentelemetry.sdk.metrics;
 
 import io.opentelemetry.sdk.metrics.data.MetricDataType;
+import io.opentelemetry.sdk.metrics.internal.view.Base2ExponentialHistogramAggregation;
 import io.opentelemetry.sdk.metrics.internal.view.DefaultAggregation;
 import io.opentelemetry.sdk.metrics.internal.view.DropAggregation;
 import io.opentelemetry.sdk.metrics.internal.view.ExplicitBucketHistogramAggregation;
-import io.opentelemetry.sdk.metrics.internal.view.ExponentialHistogramAggregation;
 import io.opentelemetry.sdk.metrics.internal.view.LastValueAggregation;
 import io.opentelemetry.sdk.metrics.internal.view.SumAggregation;
 import java.util.List;
@@ -74,7 +74,7 @@ static Aggregation explicitBucketHistogram(List<Double> bucketBoundaries) {
    * default {@code maxBuckets} and {@code maxScale}.
    */
   static Aggregation base2ExponentialBucketHistogram() {
-    return ExponentialHistogramAggregation.getDefault();
+    return Base2ExponentialHistogramAggregation.getDefault();
   }
 
   /**
@@ -88,6 +88,6 @@ static Aggregation base2ExponentialBucketHistogram() {
    *     performance of computing bucket index is improved when scale is {@code <= 0}.
    */
   static Aggregation base2ExponentialBucketHistogram(int maxBuckets, int maxScale) {
-    return ExponentialHistogramAggregation.create(maxBuckets, maxScale);
+    return Base2ExponentialHistogramAggregation.create(maxBuckets, maxScale);
   }
 }

sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/aggregator/ExponentialHistogramIndexer.java renamed to sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/aggregator/Base2ExponentialHistogramIndexer.java

@@ -8,9 +8,10 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
-final class ExponentialHistogramIndexer {
+final class Base2ExponentialHistogramIndexer {
 
-  private static final Map<Integer, ExponentialHistogramIndexer> cache = new ConcurrentHashMap<>();
+  private static final Map<Integer, Base2ExponentialHistogramIndexer> cache =
+      new ConcurrentHashMap<>();
 
   /** Bit mask used to isolate exponent of IEEE 754 double precision number. */
   private static final long EXPONENT_BIT_MASK = 0x7FF0000000000000L;
@@ -35,14 +36,14 @@ final class ExponentialHistogramIndexer {
   private final int scale;
   private final double scaleFactor;
 
-  private ExponentialHistogramIndexer(int scale) {
+  private Base2ExponentialHistogramIndexer(int scale) {
     this.scale = scale;
     this.scaleFactor = computeScaleFactor(scale);
   }
 
   /** Get an indexer for the given scale. Indexers are cached and reused for performance. */
-  static ExponentialHistogramIndexer get(int scale) {
-    return cache.computeIfAbsent(scale, unused -> new ExponentialHistogramIndexer(scale));
+  static Base2ExponentialHistogramIndexer get(int scale) {
+    return cache.computeIfAbsent(scale, unused -> new Base2ExponentialHistogramIndexer(scale));
   }
 
   /**

sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/aggregator/DoubleExponentialHistogramAggregator.java renamed to sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/aggregator/DoubleBase2ExponentialHistogramAggregator.java

@@ -28,12 +28,12 @@
 import javax.annotation.Nullable;
 
 /**
- * Aggregator that generates exponential histograms.
+ * Aggregator that generates base2 exponential histograms.
  *
  * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
  * at any time.
  */
-public final class DoubleExponentialHistogramAggregator
+public final class DoubleBase2ExponentialHistogramAggregator
     implements Aggregator<ExponentialHistogramPointData, DoubleExemplarData> {
 
   private final Supplier<ExemplarReservoir<DoubleExemplarData>> reservoirSupplier;
@@ -45,7 +45,7 @@ public final class DoubleExponentialHistogramAggregator
    *
    * @param reservoirSupplier Supplier of exemplar reservoirs per-stream.
    */
-  public DoubleExponentialHistogramAggregator(
+  public DoubleBase2ExponentialHistogramAggregator(
       Supplier<ExemplarReservoir<DoubleExemplarData>> reservoirSupplier,
       int maxBuckets,
       int maxScale) {
@@ -78,8 +78,8 @@ public MetricData toMetricData(
   static final class Handle
       extends AggregatorHandle<ExponentialHistogramPointData, DoubleExemplarData> {
     private final int maxBuckets;
-    @Nullable private DoubleExponentialHistogramBuckets positiveBuckets;
-    @Nullable private DoubleExponentialHistogramBuckets negativeBuckets;
+    @Nullable private DoubleBase2ExponentialHistogramBuckets positiveBuckets;
+    @Nullable private DoubleBase2ExponentialHistogramBuckets negativeBuckets;
     private long zeroCount;
     private double sum;
     private double min;
@@ -129,7 +129,7 @@ protected synchronized ExponentialHistogramPointData doAggregateThenMaybeReset(
     }
 
     private static ExponentialHistogramBuckets resolveBuckets(
-        @Nullable DoubleExponentialHistogramBuckets buckets, int scale, boolean reset) {
+        @Nullable DoubleBase2ExponentialHistogramBuckets buckets, int scale, boolean reset) {
       if (buckets == null) {
         return EmptyExponentialHistogramBuckets.get(scale);
       }
@@ -154,20 +154,20 @@ protected synchronized void doRecordDouble(double value) {
       count++;
 
       int c = Double.compare(value, 0);
-      DoubleExponentialHistogramBuckets buckets;
+      DoubleBase2ExponentialHistogramBuckets buckets;
       if (c == 0) {
         zeroCount++;
         return;
       } else if (c > 0) {
         // Initialize positive buckets at current scale, if needed
         if (positiveBuckets == null) {
-          positiveBuckets = new DoubleExponentialHistogramBuckets(scale, maxBuckets);
+          positiveBuckets = new DoubleBase2ExponentialHistogramBuckets(scale, maxBuckets);
         }
         buckets = positiveBuckets;
       } else {
         // Initialize negative buckets at current scale, if needed
         if (negativeBuckets == null) {
-          negativeBuckets = new DoubleExponentialHistogramBuckets(scale, maxBuckets);
+          negativeBuckets = new DoubleBase2ExponentialHistogramBuckets(scale, maxBuckets);
         }
         buckets = negativeBuckets;
       }
@@ -214,7 +214,7 @@ static ExponentialHistogramBuckets get(int scale) {
       return ZERO_BUCKETS.computeIfAbsent(
           scale,
           scale1 ->
-              new AutoValue_DoubleExponentialHistogramAggregator_EmptyExponentialHistogramBuckets(
+              new AutoValue_DoubleBase2ExponentialHistogramAggregator_EmptyExponentialHistogramBuckets(
                   scale1, 0, Collections.emptyList(), 0));
     }
   }

sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/aggregator/DoubleExponentialHistogramBuckets.java renamed to sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/aggregator/DoubleBase2ExponentialHistogramBuckets.java

@@ -12,37 +12,37 @@
 import javax.annotation.Nullable;
 
 /**
- * This class handles the operations for recording, scaling, and exposing data related to the
+ * This class handles the operations for recording, scaling, and exposing data related to the base2
  * exponential histogram.
  *
  * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
  * at any time.
  */
-final class DoubleExponentialHistogramBuckets implements ExponentialHistogramBuckets {
+final class DoubleBase2ExponentialHistogramBuckets implements ExponentialHistogramBuckets {
 
   private AdaptingCircularBufferCounter counts;
   private int scale;
-  private ExponentialHistogramIndexer exponentialHistogramIndexer;
+  private Base2ExponentialHistogramIndexer base2ExponentialHistogramIndexer;
   private long totalCount;
 
-  DoubleExponentialHistogramBuckets(int scale, int maxBuckets) {
+  DoubleBase2ExponentialHistogramBuckets(int scale, int maxBuckets) {
     this.counts = new AdaptingCircularBufferCounter(maxBuckets);
     this.scale = scale;
-    this.exponentialHistogramIndexer = ExponentialHistogramIndexer.get(this.scale);
+    this.base2ExponentialHistogramIndexer = Base2ExponentialHistogramIndexer.get(this.scale);
     this.totalCount = 0;
   }
 
   // For copying
-  DoubleExponentialHistogramBuckets(DoubleExponentialHistogramBuckets buckets) {
+  DoubleBase2ExponentialHistogramBuckets(DoubleBase2ExponentialHistogramBuckets buckets) {
     this.counts = new AdaptingCircularBufferCounter(buckets.counts);
     this.scale = buckets.scale;
-    this.exponentialHistogramIndexer = buckets.exponentialHistogramIndexer;
+    this.base2ExponentialHistogramIndexer = buckets.base2ExponentialHistogramIndexer;
     this.totalCount = buckets.totalCount;
   }
 
   /** Returns a copy of this bucket. */
-  DoubleExponentialHistogramBuckets copy() {
-    return new DoubleExponentialHistogramBuckets(this);
+  DoubleBase2ExponentialHistogramBuckets copy() {
+    return new DoubleBase2ExponentialHistogramBuckets(this);
   }
 
   /** Resets all counters in this bucket set to zero, but preserves scale. */
@@ -56,7 +56,7 @@ boolean record(double value) {
       // Guarded by caller. If passed 0 it would be a bug in the SDK.
       throw new IllegalStateException("Illegal attempted recording of zero at bucket level.");
     }
-    int index = exponentialHistogramIndexer.computeIndex(value);
+    int index = base2ExponentialHistogramIndexer.computeIndex(value);
     boolean recordingSuccessful = this.counts.increment(index, 1);
     if (recordingSuccessful) {
       totalCount++;
@@ -121,7 +121,7 @@ void downscale(int by) {
     }
 
     this.scale = this.scale - by;
-    this.exponentialHistogramIndexer = ExponentialHistogramIndexer.get(this.scale);
+    this.base2ExponentialHistogramIndexer = Base2ExponentialHistogramIndexer.get(this.scale);
   }
 
   /**
@@ -135,7 +135,7 @@ void downscale(int by) {
    *
    * @param other the histogram that will be merged into this one
    */
-  void mergeInto(DoubleExponentialHistogramBuckets other) {
+  void mergeInto(DoubleBase2ExponentialHistogramBuckets other) {
     if (other.counts.isEmpty()) {
       return;
     }
@@ -190,7 +190,7 @@ public int getScale() {
    * @return The required scale reduction in order to fit the value in these buckets.
    */
   int getScaleReduction(double value) {
-    long index = exponentialHistogramIndexer.computeIndex(value);
+    long index = base2ExponentialHistogramIndexer.computeIndex(value);
     long newStart = Math.min(index, counts.getIndexStart());
     long newEnd = Math.max(index, counts.getIndexEnd());
     return getScaleReduction(newStart, newEnd);
@@ -209,10 +209,10 @@ int getScaleReduction(long newStart, long newEnd) {
 
   @Override
   public boolean equals(@Nullable Object obj) {
-    if (!(obj instanceof DoubleExponentialHistogramBuckets)) {
+    if (!(obj instanceof DoubleBase2ExponentialHistogramBuckets)) {
       return false;
     }
-    DoubleExponentialHistogramBuckets other = (DoubleExponentialHistogramBuckets) obj;
+    DoubleBase2ExponentialHistogramBuckets other = (DoubleBase2ExponentialHistogramBuckets) obj;
     // Don't need to compare getTotalCount() because equivalent bucket counts
     // imply equivalent overall count.
     // Additionally, we compare the "semantics" of bucket counts, that is
@@ -232,7 +232,7 @@ public boolean equals(@Nullable Object obj) {
    *   <li>Offset does NOT need to be the same
    * </ul>
    */
-  private boolean sameBucketCounts(DoubleExponentialHistogramBuckets other) {
+  private boolean sameBucketCounts(DoubleBase2ExponentialHistogramBuckets other) {
     if (this.totalCount != other.totalCount) {
       return false;
     }

sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/view/ExponentialHistogramAggregation.java renamed to sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/view/Base2ExponentialHistogramAggregation.java

@@ -15,7 +15,7 @@
 import io.opentelemetry.sdk.metrics.data.PointData;
 import io.opentelemetry.sdk.metrics.internal.aggregator.Aggregator;
 import io.opentelemetry.sdk.metrics.internal.aggregator.AggregatorFactory;
-import io.opentelemetry.sdk.metrics.internal.aggregator.DoubleExponentialHistogramAggregator;
+import io.opentelemetry.sdk.metrics.internal.aggregator.DoubleBase2ExponentialHistogramAggregator;
 import io.opentelemetry.sdk.metrics.internal.descriptor.InstrumentDescriptor;
 import io.opentelemetry.sdk.metrics.internal.exemplar.ExemplarFilter;
 import io.opentelemetry.sdk.metrics.internal.exemplar.ExemplarReservoir;
@@ -26,18 +26,18 @@
  * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
  * at any time.
  */
-public final class ExponentialHistogramAggregation implements Aggregation, AggregatorFactory {
+public final class Base2ExponentialHistogramAggregation implements Aggregation, AggregatorFactory {
 
   private static final int DEFAULT_MAX_BUCKETS = 160;
   private static final int DEFAULT_MAX_SCALE = 20;
 
   private static final Aggregation DEFAULT =
-      new ExponentialHistogramAggregation(DEFAULT_MAX_BUCKETS, DEFAULT_MAX_SCALE);
+      new Base2ExponentialHistogramAggregation(DEFAULT_MAX_BUCKETS, DEFAULT_MAX_SCALE);
 
   private final int maxBuckets;
   private final int maxScale;
 
-  private ExponentialHistogramAggregation(int maxBuckets, int maxScale) {
+  private Base2ExponentialHistogramAggregation(int maxBuckets, int maxScale) {
     this.maxBuckets = maxBuckets;
     this.maxScale = maxScale;
   }
@@ -60,15 +60,15 @@ public static Aggregation getDefault() {
   public static Aggregation create(int maxBuckets, int maxScale) {
     checkArgument(maxBuckets >= 1, "maxBuckets must be > 0");
     checkArgument(maxScale <= 20 && maxScale >= -10, "maxScale must be -10 <= x <= 20");
-    return new ExponentialHistogramAggregation(maxBuckets, maxScale);
+    return new Base2ExponentialHistogramAggregation(maxBuckets, maxScale);
   }
 
   @Override
   @SuppressWarnings("unchecked")
   public <T extends PointData, U extends ExemplarData> Aggregator<T, U> createAggregator(
       InstrumentDescriptor instrumentDescriptor, ExemplarFilter exemplarFilter) {
     return (Aggregator<T, U>)
-        new DoubleExponentialHistogramAggregator(
+        new DoubleBase2ExponentialHistogramAggregator(
             () ->
                 ExemplarReservoir.filtered(
                     exemplarFilter,
@@ -93,7 +93,7 @@ public boolean isCompatibleWithInstrument(InstrumentDescriptor instrumentDescrip
 
   @Override
   public String toString() {
-    return "ExponentialHistogramAggregation{maxBuckets="
+    return "Base2ExponentialHistogramAggregation{maxBuckets="
         + maxBuckets
         + ",maxScale="
         + maxScale

sdk/metrics/src/test/java/io/opentelemetry/sdk/metrics/AggregationTest.java

@@ -29,15 +29,14 @@ void haveToString() {
         .contains("ExplicitBucketHistogramAggregation");
     assertThat(Aggregation.base2ExponentialBucketHistogram())
         .asString()
-        .isEqualTo("ExponentialHistogramAggregation{maxBuckets=160,maxScale=20}");
+        .isEqualTo("Base2ExponentialHistogramAggregation{maxBuckets=160,maxScale=20}");
     assertThat(Aggregation.base2ExponentialBucketHistogram(1, 0))
         .asString()
-        .isEqualTo("ExponentialHistogramAggregation{maxBuckets=1,maxScale=0}");
+        .isEqualTo("Base2ExponentialHistogramAggregation{maxBuckets=1,maxScale=0}");
   }
 
   @Test
   void histogramUsesExplicitBucket() {
-    // Note: This will change when exponential histograms are launched.
     assertThat(Aggregation.explicitBucketHistogram())
         .asString()
         .contains("ExplicitBucketHistogram");