Add docs and license

core/src/main/java/org/apache/gravitino/listener/api/event/ListTagFailureEvent.java

@@ -1,19 +1,59 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
 package org.apache.gravitino.listener.api.event;
 
 import org.apache.gravitino.NameIdentifier;
-
+import org.apache.gravitino.annotation.DeveloperApi;
+/**
+ * Represents an event triggered when an attempt to list tags fails due to an exception.
+ */
+@DeveloperApi
 public class ListTagFailureEvent extends TagFailureEvent {
   private final String metalake;
 
+  /**
+   * Constructs a new {@code ListTagFailureEvent} instance.
+   *
+   * @param user The user who initiated the tag listing operation.
+   * @param metalake The metalake name where the tags are being listed.
+   * @param exception The exception encountered during the tag listing operation, providing insights into the reasons behind the failure.
+   */
   public ListTagFailureEvent(String user, String metalake, Exception exception) {
     super(user, NameIdentifier.of(metalake), exception);
     this.metalake = metalake;
   }
 
+  /**
+   * Returns the metalake name where the tags are being listed.
+   *
+   * @return The metalake name.
+   */
   public String metalake() {
     return metalake;
   }
 
+  /**
+   * Returns the type of operation.
+   *
+   * @return the operation type.
+   */
   @Override
   public OperationType operationType() {
     return OperationType.LIST_TAG;

core/src/main/java/org/apache/gravitino/listener/api/event/ListTagsInfoFailureEvent.java

@@ -1,19 +1,60 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
 package org.apache.gravitino.listener.api.event;
 
 import org.apache.gravitino.NameIdentifier;
+import org.apache.gravitino.annotation.DeveloperApi;  
 
+/**
+ * Represents an event triggered when an attempt to list tag information fails due to an exception.
+ */
+@DeveloperApi
 public class ListTagsInfoFailureEvent extends FailureEvent {
   private final String metalake;
 
+  /**
+   * Constructs a new {@code ListTagsInfoFailureEvent} instance.
+   *
+   * @param user The user who initiated the tag listing operation.
+   * @param metalake The metalake name where the tags are being listed.
+   * @param exception The exception encountered during the tag listing operation, providing insights into the reasons behind the failure.
+   */
   public ListTagsInfoFailureEvent(String user, String metalake, Exception exception) {
     super(user, NameIdentifier.of(metalake), exception);
     this.metalake = metalake;
   }
 
+  /**
+   * Returns the metalake name where the tags are being listed.
+   *
+   * @return The metalake name.
+   */
   public String metalake() {
     return metalake;
   }
 
+  /**
+   * Returns the type of operation.
+   *
+   * @return the operation type.
+   */
   @Override
   public OperationType operationType() {
     return OperationType.LIST_TAGS_INFO;

core/src/main/java/org/apache/gravitino/listener/api/event/TagFailureEvent.java

@@ -1,8 +1,40 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
 package org.apache.gravitino.listener.api.event;
 
 import org.apache.gravitino.NameIdentifier;
+import org.apache.gravitino.annotation.DeveloperApi;
 
+/**
+ * Represents an event triggered when an attempt to perform a tag operation fails due to an exception.
+ */
+@DeveloperApi
 public class TagFailureEvent extends FailureEvent {
+
+  /**
+   * Constructs a new {@code TagFailureEvent} instance.
+   *
+   * @param user The user who initiated the tag operation.
+   * @param identifier The identifier of the tag involved in the operation.
+   * @param exception The exception encountered during the tag operation, providing insights into the reasons behind the failure.
+   */
   public TagFailureEvent(String user, NameIdentifier identifier, Exception exception) {
     super(user, identifier, exception);
   }

core/src/main/java/org/apache/gravitino/listener/api/info/TagInfo.java

@@ -1,10 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
 package org.apache.gravitino.listener.api.info;
 
-import com.google.common.collect.ImmutableMap;
 import java.util.Map;
+
 import javax.annotation.Nullable;
+
 import org.apache.gravitino.annotation.DeveloperApi;
 
+import com.google.common.collect.ImmutableMap;
+
 /**
  * Provides access to metadata about a Tag instance, designed for use by event listeners. This class
  * encapsulates the essential attributes of a Tag, including its name, optional description,

core/src/test/java/org/apache/gravitino/listener/api/event/TestTagEvent.java

@@ -1,10 +1,26 @@
-package org.apache.gravitino.listener.api.event;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
 
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
+package org.apache.gravitino.listener.api.event;
 
-import com.google.common.collect.ImmutableMap;
 import java.util.Arrays;
+
 import org.apache.gravitino.Entity;
 import org.apache.gravitino.MetadataObject;
 import org.apache.gravitino.exceptions.GravitinoRuntimeException;
@@ -20,6 +36,10 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestInstance;
 import org.junit.jupiter.api.TestInstance.Lifecycle;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import com.google.common.collect.ImmutableMap;
 
 @TestInstance(Lifecycle.PER_CLASS)
 public class TestTagEvent {