add javadoc to public classes

Author: psx95

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/AttributeKeys.java

@@ -15,6 +15,10 @@
  */
 package com.google.cloud.opentelemetry.detectors;
 
+/**
+ * Contains constants that act as keys for the known attributes for {@link
+ * com.google.cloud.opentelemetry.detectors.GCPPlatformDetector.SupportedPlatform}s.
+ */
 public final class AttributeKeys {
   // GCE Attributes
   public static final String GCE_PROJECT_ID = AttributeKeys.PROJECT_ID;

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/DetectedPlatform.java

@@ -17,8 +17,21 @@
 
 import java.util.Map;
 
+/** Represents a GCP specific platform on which a cloud application can run. */
 public interface DetectedPlatform {
+  /**
+   * Method to retrieve the underlying compute platform on which application is running.
+   *
+   * @return the {@link GCPPlatformDetector.SupportedPlatform} representing the Google Cloud
+   *     platform on which application is running.
+   */
   GCPPlatformDetector.SupportedPlatform getSupportedPlatform();
 
+  /**
+   * Method to retrieve the attributes associated with the compute platform on which the application
+   * is running as key-value pairs.
+   *
+   * @return a {@link Map} of attributes specific to the underlying compute platform.
+   */
   Map<String, String> getAttributes();
 }

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/GCPPlatformDetector.java

@@ -32,7 +32,11 @@ private GCPPlatformDetector() {
     this.environmentVariables = EnvironmentVariables.DEFAULT_INSTANCE;
   }
 
-  // Detects the GCP platform on which the application is running
+  /**
+   * Detects the GCP platform on which the application is running.
+   *
+   * @return the specific GCP platform on which the application is running.
+   */
   public DetectedPlatform detectPlatform() {
     return generateDetectedPlatform(detectSupportedPlatform());
   }
@@ -83,12 +87,22 @@ private DetectedPlatform generateDetectedPlatform(SupportedPlatform platform) {
     return detectedPlatform;
   }
 
+  /**
+   * SupportedPlatform represents the GCP platforms that can currently be detected by the
+   * resource-detector.
+   */
   public enum SupportedPlatform {
+    /** Represents the Google Compute Engine platform. */
     GOOGLE_COMPUTE_ENGINE,
+    /** Represents the Google Kubernetes Engine platform. */
     GOOGLE_KUBERNETES_ENGINE,
+    /** Represents the Google App Engine platform. Could either be flex or standard. */
     GOOGLE_APP_ENGINE,
+    /** Represents the Google Cloud Run platform. */
     GOOGLE_CLOUD_RUN,
+    /** Represents the Google Cloud Functions platform. */
     GOOGLE_CLOUD_FUNCTIONS,
-    UNKNOWN_PLATFORM, // Not running on GCP
+    /** Represents the case when the application is not running on GCP. */
+    UNKNOWN_PLATFORM,
   }
 }

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/GoogleKubernetesEngine.java

@@ -30,7 +30,6 @@
 import java.util.Map;
 import java.util.Optional;
 
-/** Utility class to help add GKE specific attributes to a given resource */
 final class GoogleKubernetesEngine implements DetectedPlatform {
   private final EnvironmentVariables environmentVariables;
   private final GCPMetadataConfig metadataConfig;

detectors/resources-support/src/main/java/com/google/cloud/opentelemetry/detectors/GoogleServerlessCompute.java

@@ -20,7 +20,8 @@
 import java.util.Map;
 
 /**
- * Utility class to help add attributes applicable to serverless compute in GCP to a given resource.
+ * GoogleServerlessCompute adds attributes applicable to all serverless compute platforms in GCP.
+ * Currently, this includes Google Cloud Functions & Google Cloud Run.
  */
 abstract class GoogleServerlessCompute implements DetectedPlatform {
   private final EnvironmentVariables environmentVariables;