Refactoring.

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ComposableSampler.java

@@ -5,96 +5,14 @@
 
 package io.opentelemetry.contrib.sampler.consistent56;
 
-import static io.opentelemetry.contrib.sampler.consistent56.ConsistentSamplingUtil.getInvalidRandomValue;
-import static io.opentelemetry.contrib.sampler.consistent56.ConsistentSamplingUtil.isValidThreshold;
-
 import io.opentelemetry.api.common.Attributes;
-import io.opentelemetry.api.trace.Span;
-import io.opentelemetry.api.trace.SpanContext;
 import io.opentelemetry.api.trace.SpanKind;
-import io.opentelemetry.api.trace.TraceState;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.sdk.trace.data.LinkData;
-import io.opentelemetry.sdk.trace.samplers.SamplingDecision;
-import io.opentelemetry.sdk.trace.samplers.SamplingResult;
 import java.util.List;
 
-/** Abstract base class for composable consistent samplers. */
-public abstract class ComposableSampler extends ConsistentSampler {
-
-  @Override
-  public final SamplingResult shouldSample(
-      Context parentContext,
-      String traceId,
-      String name,
-      SpanKind spanKind,
-      Attributes attributes,
-      List<LinkData> parentLinks) {
-    Span parentSpan = Span.fromContext(parentContext);
-    SpanContext parentSpanContext = parentSpan.getSpanContext();
-
-    TraceState parentTraceState = parentSpanContext.getTraceState();
-    String otelTraceStateString = parentTraceState.get(OtelTraceState.TRACE_STATE_KEY);
-    OtelTraceState otelTraceState = OtelTraceState.parse(otelTraceStateString);
-
-    SamplingIntent intent =
-        getSamplingIntent(parentContext, name, spanKind, attributes, parentLinks);
-    long threshold = intent.getThreshold();
-
-    // determine sampling decision
-    boolean isSampled;
-    if (isValidThreshold(threshold)) {
-      long randomness = getRandomness(otelTraceState, traceId);
-      isSampled = threshold <= randomness;
-    } else { // DROP
-      isSampled = false;
-    }
-
-    SamplingDecision samplingDecision;
-    if (isSampled) {
-      samplingDecision = SamplingDecision.RECORD_AND_SAMPLE;
-      otelTraceState.setThreshold(threshold);
-    } else {
-      samplingDecision = SamplingDecision.DROP;
-      otelTraceState.invalidateThreshold();
-    }
-
-    String newOtTraceState = otelTraceState.serialize();
-
-    return new SamplingResult() {
-
-      @Override
-      public SamplingDecision getDecision() {
-        return samplingDecision;
-      }
-
-      @Override
-      public Attributes getAttributes() {
-        return intent.getAttributes();
-      }
-
-      @Override
-      public TraceState getUpdatedTraceState(TraceState parentTraceState) {
-        return intent.updateTraceState(parentTraceState).toBuilder()
-            .put(OtelTraceState.TRACE_STATE_KEY, newOtTraceState)
-            .build();
-      }
-    };
-  }
-
-  private static long getRandomness(OtelTraceState otelTraceState, String traceId) {
-    if (otelTraceState.hasValidRandomValue()) {
-      return otelTraceState.getRandomValue();
-    } else {
-      return OtelTraceState.parseHex(traceId, 18, 14, getInvalidRandomValue());
-    }
-  }
-
-  @Override
-  protected final long getThreshold(long parentThreshold, boolean isRoot) {
-    // not used by Composable Samplers
-    throw new UnsupportedOperationException();
-  }
+/** An interface for components to be used by composite consistent probability samplers. */
+public interface ComposableSampler {
 
   /**
    * Returns the SamplingIntent that is used for the sampling decision. The SamplingIntent includes
@@ -105,10 +23,13 @@ protected final long getThreshold(long parentThreshold, boolean isRoot) {
    * not be used for the calculation of the threshold as the sampled flag depends itself on the
    * random value.
    */
-  protected abstract SamplingIntent getSamplingIntent(
+  SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,
       Attributes attributes,
       List<LinkData> parentLinks);
+
+  /** Return the string providing a description of the implementation */
+  String getDescription();
 }

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ConsistentAlwaysOffSampler.java

@@ -15,7 +15,7 @@
 import javax.annotation.concurrent.Immutable;
 
 @Immutable
-final class ConsistentAlwaysOffSampler extends ComposableSampler {
+final class ConsistentAlwaysOffSampler extends ConsistentSampler {
 
   private static final ConsistentAlwaysOffSampler INSTANCE = new ConsistentAlwaysOffSampler();
 
@@ -26,7 +26,7 @@ static ConsistentAlwaysOffSampler getInstance() {
   }
 
   @Override
-  protected SamplingIntent getSamplingIntent(
+  public SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ConsistentAlwaysOnSampler.java

@@ -15,7 +15,7 @@
 import javax.annotation.concurrent.Immutable;
 
 @Immutable
-final class ConsistentAlwaysOnSampler extends ComposableSampler {
+final class ConsistentAlwaysOnSampler extends ConsistentSampler {
 
   private static final ConsistentAlwaysOnSampler INSTANCE = new ConsistentAlwaysOnSampler();
 
@@ -26,7 +26,7 @@ static ConsistentAlwaysOnSampler getInstance() {
   }
 
   @Override
-  protected SamplingIntent getSamplingIntent(
+  public SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ConsistentAnyOf.java

@@ -22,7 +22,7 @@
  * uses the minimum threshold value received.
  */
 @Immutable
-final class ConsistentAnyOf extends ComposableSampler {
+final class ConsistentAnyOf extends ConsistentSampler {
 
   private final ComposableSampler[] delegates;
 
@@ -53,7 +53,7 @@ final class ConsistentAnyOf extends ComposableSampler {
   }
 
   @Override
-  protected SamplingIntent getSamplingIntent(
+  public SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ConsistentFixedThresholdSampler.java

@@ -16,7 +16,7 @@
 import io.opentelemetry.sdk.trace.data.LinkData;
 import java.util.List;
 
-public class ConsistentFixedThresholdSampler extends ComposableSampler {
+public class ConsistentFixedThresholdSampler extends ConsistentSampler {
 
   private final long threshold;
   private final String description;
@@ -49,7 +49,7 @@ public String getDescription() {
   }
 
   @Override
-  protected SamplingIntent getSamplingIntent(
+  public SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ConsistentParentBasedSampler.java

@@ -23,7 +23,7 @@
  * sampling decision is delegated to the root sampler.
  */
 @Immutable
-final class ConsistentParentBasedSampler extends ComposableSampler {
+final class ConsistentParentBasedSampler extends ConsistentSampler {
 
   private final ComposableSampler rootSampler;
 
@@ -42,7 +42,7 @@ final class ConsistentParentBasedSampler extends ComposableSampler {
   }
 
   @Override
-  protected SamplingIntent getSamplingIntent(
+  public SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ConsistentRateLimitingSampler.java

@@ -93,7 +93,7 @@
  *
  * <p>{@code 1 / (adaptationTimeSeconds * targetSpansPerSecondLimit)}
  */
-final class ConsistentRateLimitingSampler extends ComposableSampler {
+final class ConsistentRateLimitingSampler extends ConsistentSampler {
 
   private static final double NANOS_IN_SECONDS = 1e-9;
 
@@ -189,7 +189,7 @@ private State updateState(State oldState, long currentNanoTime, double delegateP
   }
 
   @Override
-  protected SamplingIntent getSamplingIntent(
+  public SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,

consistent-sampling/src/main/java/io/opentelemetry/contrib/sampler/consistent56/ConsistentRuleBasedSampler.java

@@ -21,7 +21,7 @@
  * ComposableSamplers into PredicatedSamplers.
  */
 @Immutable
-final class ConsistentRuleBasedSampler extends ComposableSampler {
+final class ConsistentRuleBasedSampler extends ConsistentSampler {
 
   @Nullable private final SpanKind spanKindToMatch;
   private final PredicatedSampler[] samplers;
@@ -57,7 +57,7 @@ private ConsistentRuleBasedSampler(
   }
 
   @Override
-  protected SamplingIntent getSamplingIntent(
+  public SamplingIntent getSamplingIntent(
       Context parentContext,
       String name,
       SpanKind spanKind,