add comments and address compiler errors

Signed-off-by: Kaituo Li <[email protected]>

src/main/java/org/opensearch/ad/cluster/ClusterManagerEventListener.java

@@ -20,7 +20,7 @@
 import org.opensearch.client.Client;
 import org.opensearch.cluster.LocalNodeClusterManagerListener;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.component.LifecycleListener;
+import org.opensearch.common.lifecycle.LifecycleListener;
 import org.opensearch.common.settings.Setting;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;

src/main/java/org/opensearch/forecast/model/ForecastTaskType.java

@@ -17,6 +17,28 @@
 
 import com.google.common.collect.ImmutableList;
 
+/**
+ * The ForecastTaskType enum defines different task types for forecasting, categorized into real-time and historical settings.
+ * In real-time forecasting, we monitor states at the forecaster level, resulting in two distinct task types: one for
+ * single-stream forecasting and another for high cardinality (HC). In the historical setting, state tracking is more nuanced,
+ * encompassing both entity and forecaster levels. This leads to three specific task types: a forecaster-level task dedicated
+ * to single-stream forecasting, and two tasks for HC, one at the forecaster level and another at the entity level.
+ *
+ * Real-time forecasting:
+ * - FORECAST_REALTIME_SINGLE_STREAM: Represents a task type for single-stream forecasting. Ideal for scenarios where a single
+ *  time series is processed in real-time.
+ * - FORECAST_REALTIME_HC_FORECASTER: Represents a task type for high cardinality (HC) forecasting. Used when dealing with a
+ *  large number of distinct entities in real-time.
+ *
+ * Historical forecasting:
+ * - FORECAST_HISTORICAL_SINGLE_STREAM: Represents a forecaster-level task for single-stream historical forecasting.
+ * Suitable for analyzing a single time series in a sequential manner.
+ * - FORECAST_HISTORICAL_HC_FORECASTER: A forecaster-level task to track overall state, initialization progress, errors, etc.,
+ * for HC forecasting. Central to managing multiple historical time series with high cardinality.
+ * - FORECAST_HISTORICAL_HC_ENTITY: An entity-level task to track the state, initialization progress, errors, etc., of a
+ * specific entity within HC historical forecasting. Allows for fine-grained information recording at the entity level.
+ *
+ */
 public enum ForecastTaskType implements TaskType {
     FORECAST_REALTIME_SINGLE_STREAM,
     FORECAST_REALTIME_HC_FORECASTER,

src/test/java/org/opensearch/ad/MemoryTrackerTests.java

@@ -24,7 +24,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.monitor.jvm.JvmInfo.Mem;
 import org.opensearch.monitor.jvm.JvmService;

src/test/java/org/opensearch/ad/caching/PriorityCacheTests.java

@@ -57,7 +57,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
-import org.opensearch.common.unit.ByteSizeValue;
+import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.monitor.jvm.JvmInfo;
 import org.opensearch.monitor.jvm.JvmInfo.Mem;
 import org.opensearch.monitor.jvm.JvmService;

src/test/java/org/opensearch/ad/cluster/ClusterManagerEventListenerTests.java

@@ -32,7 +32,7 @@
 import org.opensearch.ad.settings.AnomalyDetectorSettings;
 import org.opensearch.client.Client;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.component.LifecycleListener;
+import org.opensearch.common.lifecycle.LifecycleListener;
 import org.opensearch.common.settings.ClusterSettings;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;

src/test/java/org/opensearch/ad/transport/StopDetectorActionTests.java

@@ -21,9 +21,9 @@
 import org.opensearch.action.ActionResponse;
 import org.opensearch.common.Strings;
 import org.opensearch.common.io.stream.BytesStreamOutput;
-import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.common.io.stream.StreamOutput;
+import org.opensearch.core.xcontent.MediaTypeRegistry;
 import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.test.OpenSearchIntegTestCase;
@@ -91,7 +91,7 @@ public void writeTo(StreamOutput streamOutput) throws IOException {
     @Test
     public void toXContentTest() throws IOException {
         StopDetectorResponse stopDetectorResponse = new StopDetectorResponse(true);
-        XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);
+        XContentBuilder builder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
         stopDetectorResponse.toXContent(builder, ToXContent.EMPTY_PARAMS);
         assertNotNull(builder);
         String jsonStr = Strings.toString(builder);

src/test/java/org/opensearch/timeseries/TestHelpers.java

@@ -1420,6 +1420,19 @@ public static ADTask randomAdTask(
         return task;
     }
 
+    /**
+     * Generates a random Entity based on the provided configuration.
+     *
+     * If the configuration has multiple categories, a new Entity is created with attributes
+     * populated with random alphanumeric strings of length 5.
+     *
+     * If the configuration is marked as high cardinality and does not have multiple categories,
+     * a new Entity is created with a single attribute using the first category field and a random
+     * alphanumeric string of length 5.
+     *
+     * @param config The configuration object containing information about a time series analysis.
+     * @return A randomly generated Entity based on the configuration, or null if the config is null.
+     */
     public static Entity randomEntity(Config config) {
         Entity entity = null;
         if (config != null) {

src/test/java/org/opensearch/timeseries/feature/NoPowermockSearchFeatureDaoTests.java

@@ -67,9 +67,9 @@
 import org.opensearch.common.util.BitMixer;
 import org.opensearch.common.util.MockBigArrays;
 import org.opensearch.common.util.MockPageCacheRecycler;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.index.mapper.DateFieldMapper;
 import org.opensearch.index.query.QueryBuilders;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.search.DocValueFormat;
 import org.opensearch.search.SearchHit;
 import org.opensearch.search.SearchHits;

src/test/java/test/org/opensearch/ad/util/FakeNode.java

@@ -45,7 +45,7 @@
 import org.opensearch.common.transport.TransportAddress;
 import org.opensearch.common.util.PageCacheRecycler;
 import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
-import org.opensearch.indices.breaker.NoneCircuitBreakerService;
+import org.opensearch.core.indices.breaker.NoneCircuitBreakerService;
 import org.opensearch.tasks.TaskManager;
 import org.opensearch.tasks.TaskResourceTrackingService;
 import org.opensearch.test.OpenSearchTestCase;