Merge PR #412: Update samplers module to follow style guide

Author: trask

samplers/build.gradle.kts

@@ -13,6 +13,10 @@ dependencies {
   compileOnly("io.opentelemetry:opentelemetry-api-incubator")
   compileOnly("io.opentelemetry:opentelemetry-sdk-extension-incubator")
 
+  annotationProcessor("com.google.auto.service:auto-service")
+  compileOnly("com.google.auto.service:auto-service-annotations")
+
+  testImplementation("com.google.auto.service:auto-service")
   testImplementation("io.opentelemetry.semconv:opentelemetry-semconv-incubating")
   testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure")
   testImplementation("io.opentelemetry:opentelemetry-sdk-extension-incubator")

samplers/src/main/java/io/opentelemetry/contrib/sampler/LinksBasedSampler.java

@@ -37,7 +37,7 @@ public SamplingResult shouldSample(
       SpanKind spanKind,
       Attributes attributes,
       List<LinkData> parentLinks) {
-    if (parentLinks.size() > 0) {
+    if (!parentLinks.isEmpty()) {
       for (LinkData linkData : parentLinks) {
         if (linkData.getSpanContext().isSampled()) {
           return SamplingResult.recordAndSample();

samplers/src/main/java/io/opentelemetry/contrib/sampler/LinksParentAlwaysOnSamplerProvider.java

@@ -5,11 +5,13 @@
 
 package io.opentelemetry.contrib.sampler;
 
+import com.google.auto.service.AutoService;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
 import io.opentelemetry.sdk.autoconfigure.spi.traces.ConfigurableSamplerProvider;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 
-public class LinksParentAlwaysOnSamplerProvider implements ConfigurableSamplerProvider {
+@AutoService(ConfigurableSamplerProvider.class)
+public final class LinksParentAlwaysOnSamplerProvider implements ConfigurableSamplerProvider {
   @Override
   public Sampler createSampler(ConfigProperties config) {
     return LinksBasedSampler.create(Sampler.parentBased(Sampler.alwaysOn()));

samplers/src/main/java/io/opentelemetry/contrib/sampler/SamplingRule.java

@@ -5,9 +5,10 @@
 
 package io.opentelemetry.contrib.sampler;
 
+import static java.util.Objects.hash;
+
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
-import java.util.Objects;
 import java.util.regex.Pattern;
 import javax.annotation.Nullable;
 
@@ -48,6 +49,6 @@ public boolean equals(@Nullable Object o) {
 
   @Override
   public int hashCode() {
-    return Objects.hash(attributeKey, pattern);
+    return hash(attributeKey, pattern);
   }
 }

samplers/src/main/java/io/opentelemetry/contrib/sampler/internal/RuleBasedRoutingSamplerComponentProvider.java

@@ -5,6 +5,7 @@
 
 package io.opentelemetry.contrib.sampler.internal;
 
+import com.google.auto.service.AutoService;
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.incubator.config.DeclarativeConfigException;
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
@@ -22,6 +23,8 @@
  * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
  * at any time.
  */
+@SuppressWarnings("rawtypes")
+@AutoService(ComponentProvider.class)
 public class RuleBasedRoutingSamplerComponentProvider implements ComponentProvider<Sampler> {
 
   private static final String ACTION_RECORD_AND_SAMPLE = "RECORD_AND_SAMPLE";