Update baggage-processor module to follow style guide conventions

Co-authored-by: trask <[email protected]>

Author: Copilot

baggage-processor/build.gradle.kts

@@ -8,10 +8,14 @@ description = "OpenTelemetry Baggage Span Processor"
 otelJava.moduleName.set("io.opentelemetry.contrib.baggage.processor")
 
 dependencies {
+  annotationProcessor("com.google.auto.service:auto-service")
+
   api("io.opentelemetry:opentelemetry-api")
   api("io.opentelemetry:opentelemetry-sdk")
+  compileOnly("com.google.auto.service:auto-service")
   implementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure-spi")
 
+  testImplementation("com.google.auto.service:auto-service")
   testImplementation("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure")
   testImplementation("io.opentelemetry:opentelemetry-sdk-testing")
   testImplementation("org.mockito:mockito-inline")

baggage-processor/src/main/java/io/opentelemetry/contrib/baggage/processor/BaggageLogRecordProcessor.java

@@ -16,15 +16,7 @@
  * This log record processor copies attributes stored in {@link Baggage} into each newly created log
  * record.
  */
-public class BaggageLogRecordProcessor implements LogRecordProcessor {
-
-  /**
-   * Creates a new {@link BaggageLogRecordProcessor} that copies all baggage entries into the newly
-   * created log record.
-   */
-  public static BaggageLogRecordProcessor allowAllBaggageKeys() {
-    return new BaggageLogRecordProcessor(baggageKey -> true);
-  }
+public final class BaggageLogRecordProcessor implements LogRecordProcessor {
 
   private final Predicate<String> baggageKeyPredicate;
 
@@ -36,6 +28,14 @@ public BaggageLogRecordProcessor(Predicate<String> baggageKeyPredicate) {
     this.baggageKeyPredicate = baggageKeyPredicate;
   }
 
+  /**
+   * Creates a new {@link BaggageLogRecordProcessor} that copies all baggage entries into the newly
+   * created log record.
+   */
+  public static BaggageLogRecordProcessor allowAllBaggageKeys() {
+    return new BaggageLogRecordProcessor(baggageKey -> true);
+  }
+
   @Override
   public void onEmit(Context context, ReadWriteLogRecord logRecord) {
     Baggage.fromContext(context)

baggage-processor/src/main/java/io/opentelemetry/contrib/baggage/processor/BaggageProcessorCustomizer.java

@@ -5,14 +5,16 @@
 
 package io.opentelemetry.contrib.baggage.processor;
 
+import com.google.auto.service.AutoService;
 import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizer;
 import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizerProvider;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
 import io.opentelemetry.sdk.logs.SdkLoggerProviderBuilder;
 import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
 import java.util.List;
 
-public class BaggageProcessorCustomizer implements AutoConfigurationCustomizerProvider {
+@AutoService(AutoConfigurationCustomizerProvider.class)
+public final class BaggageProcessorCustomizer implements AutoConfigurationCustomizerProvider {
   @Override
   public void customize(AutoConfigurationCustomizer autoConfigurationCustomizer) {
     autoConfigurationCustomizer

baggage-processor/src/main/java/io/opentelemetry/contrib/baggage/processor/BaggageSpanProcessor.java

@@ -16,7 +16,7 @@
  * This span processor copies attributes stored in {@link Baggage} into each newly created {@link
  * io.opentelemetry.api.trace.Span}.
  */
-public class BaggageSpanProcessor implements SpanProcessor {
+public final class BaggageSpanProcessor implements SpanProcessor {
   private final Predicate<String> baggageKeyPredicate;
 
   /**