Add javadocs in missing locations

src/main/java/org/opensearch/ubi/QueryRequest.java

@@ -40,6 +40,7 @@ public class QueryRequest {
      * @param userQuery The user-entered query.
      * @param clientId The ID of the client that initiated the query.
      * @param query The raw query.
+     * @param application The application that initiated the query.
      * @param queryAttributes An optional map of additional attributes for the query.
      * @param queryResponse The {@link QueryResponse} for this query request.
      */

src/main/java/org/opensearch/ubi/UbiPlugin.java

@@ -49,10 +49,22 @@
  */
 public class UbiPlugin extends Plugin implements ActionPlugin, SearchPlugin, TelemetryAwarePlugin {
 
+    /**
+     * The index name used for storing User Behavior Insights queries data.
+     */
     public static final String UBI_QUERIES_INDEX = "ubi_queries";
+    /**
+     * The index name used for storing User Behavior Insights events data.
+     */
     public static final String UBI_EVENTS_INDEX = "ubi_events";
 
+    /**
+     * Path to the JSON file containing the mapping configuration for the events index.
+     */
     public static final String EVENTS_MAPPING_FILE = "/events-mapping.json";
+    /**
+     * Path to the JSON file containing the mapping configuration for the queries index.
+     */
     public static final String QUERIES_MAPPING_FILE = "/queries-mapping.json";
 
     private ActionFilter ubiActionFilter;

src/main/java/org/opensearch/ubi/UbiRestHandler.java

@@ -35,6 +35,10 @@
 import static org.opensearch.ubi.UbiPlugin.UBI_EVENTS_INDEX;
 import static org.opensearch.ubi.UbiPlugin.UBI_QUERIES_INDEX;
 
+/**
+ * REST handler for User Behavior Insights Plugin operations.
+ * Provides endpoints for initializing UBI indices and mappings.
+ */
 public class UbiRestHandler extends BaseRestHandler {
 
     private static final Logger LOGGER = LogManager.getLogger(UbiRestHandler.class);
@@ -43,6 +47,13 @@ public class UbiRestHandler extends BaseRestHandler {
      * URL for initializing the plugin and the index mappings.
      */
     public static final String INITIALIZE_URL = "/_plugins/ubi/initialize";
+
+    /**
+     * Creates a new instance of {@link UbiRestHandler}.
+     */
+    public UbiRestHandler() {
+        // Default constructor
+    }
 
     @Override
     public String getName() {

src/main/java/org/opensearch/ubi/UbiSettings.java

@@ -14,10 +14,17 @@
 import java.util.List;
 
 /**
- * The UBI settings.
+ * Utility class for UBI settings.
  */
 public class UbiSettings {
 
+    /**
+     * Private constructor to prevent instantiation as this is a utility class with static methods.
+     */
+    private UbiSettings() {
+        // Private constructor to prevent instantiation
+    }
+
     /**
      * The name of the Data Prepper http_source URL for receiving queries.
      */