Address PR comments

(cherry picked from commit 1748681)

Author: bradskuse

kafka/src/main/java/org/axonframework/extensions/kafka/eventhandling/consumer/AsyncFetcher.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010-2022. Axon Framework
+ * Copyright (c) 2010-2025. Axon Framework
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -94,26 +94,26 @@ protected AsyncFetcher(Builder<K, V, E> builder) {
      */
     @Override
     public Registration poll(Consumer<K, V> consumer,
-                             RecordConverter<K, V, E> recordConverter,
-                             EventConsumer<E> eventConsumer) {
+            RecordConverter<K, V, E> recordConverter,
+            EventConsumer<E> eventConsumer) {
         return poll(consumer, recordConverter, eventConsumer,
-                    e -> logger.warn("Error from fetching thread, should be handled properly", e));
+                e -> logger.warn("Error from fetching thread, should be handled properly", e));
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Registration poll(Consumer<K, V> consumer, RecordConverter<K, V, E> recordConverter,
-                             EventConsumer<E> eventConsumer, RuntimeErrorHandler runtimeErrorHandler) {
+            EventConsumer<E> eventConsumer, RuntimeErrorHandler runtimeErrorHandler) {
         FetchEventsTask<K, V, E> fetcherTask =
                 new FetchEventsTask<>(consumer,
-                                      pollTimeout,
-                                      recordConverter,
-                                      eventConsumer,
-                                      activeFetchers::remove,
-                                      runtimeErrorHandler,
-                                      offsetCommitType);
+                        pollTimeout,
+                        recordConverter,
+                        eventConsumer,
+                        activeFetchers::remove,
+                        runtimeErrorHandler,
+                        offsetCommitType);
 
         activeFetchers.add(fetcherTask);
         executorService.execute(fetcherTask);
@@ -162,22 +162,32 @@ public static final class Builder<K, V, E> {
          */
         public Builder<K, V, E> pollTimeout(long timeoutMillis) {
             assertThat(timeoutMillis, timeout -> timeout > 0,
-                       "The poll timeout may not be negative [" + timeoutMillis + "]");
+                    "The poll timeout may not be negative [" + timeoutMillis + "]");
             this.pollTimeout = Duration.ofMillis(timeoutMillis);
             return this;
         }
 
         /**
-         * Set the {@code offsetCommitType}, options are:
-         * {@link OffsetCommitType#AUTO} let the Kafka consumer commit offsets automatically in background
-         * {@link OffsetCommitType#COMMIT_SYNC} let the Kafka consumer commit offsets synchronously after processing
-         * {@link OffsetCommitType#COMMIT_ASYNC} let the Kafka consumer commit offsets asynchronously after processing
-         * Defaults to {@code OffsetCommitType#AUTO}
+         * Sets the {@code offsetCommitType} defining how the {@link FetchEventsTask} will commit offsets during
+         * processing of events.
+         * <p>
+         * Options are:
+         * <ul>
+         *     <li>{@link OffsetCommitType#AUTO} - let the Kafka consumer commit offsets automatically in background.
+         *     </li>
+         *     <li>{@link OffsetCommitType#COMMIT_SYNC} - let the Kafka consumer commit offsets synchronously after
+         *     processing.</li>
+         *     <li>{@link OffsetCommitType#COMMIT_ASYNC} - let the Kafka consumer commit offsets asynchronously after
+         *     processing.</li>
+         * </ul>
+         * <p>
+         * Defaults to {@code OffsetCommitType#AUTO}, meaning the offset commit task happens in the background.
          *
          * @param offsetCommitType {@link OffsetCommitType} enum to specify the offset commit type
          * @return the current Builder instance, for fluent interfacing
          */
         public AsyncFetcher.Builder<K, V, E> offsetCommitType(OffsetCommitType offsetCommitType) {
+            assertNonNull(offsetCommitType, "OffsetCommitType may not be null");
             this.offsetCommitType = offsetCommitType;
             return this;
         }

kafka/src/main/java/org/axonframework/extensions/kafka/eventhandling/consumer/FetchEventsTask.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010-2022. Axon Framework
+ * Copyright (c) 2010-2025. Axon Framework
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

kafka/src/main/java/org/axonframework/extensions/kafka/eventhandling/consumer/OffsetCommitType.java

@@ -1,10 +1,47 @@
+/*
+ * Copyright (c) 2010-2025. Axon Framework
+ *
+ * Licensed 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.axonframework.extensions.kafka.eventhandling.consumer;
 
+import org.apache.kafka.clients.consumer.KafkaConsumer;
+
 /**
  * Enum to define how the consumer will handle committing offsets.
+ *
+ * @author Bradley Skuse
+ * @since 4.11.1
  */
 public enum OffsetCommitType {
+
+    /**
+     * Kafka consumer will commit offsets automatically in the background.
+     */
     AUTO,
+
+    /**
+     * Kafka consumer will commit offsets asynchronously after processing
+     *
+     * @see KafkaConsumer#commitAsync()
+     */
     COMMIT_ASYNC,
+
+    /**
+     * Kafka consumer will commit offsets synchronously after processing
+     *
+     * @see KafkaConsumer#commitSync()
+     */
     COMMIT_SYNC
 }

kafka/src/test/java/org/axonframework/extensions/kafka/eventhandling/consumer/FetchEventsTaskTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010-2022. Axon Framework
+ * Copyright (c) 2010-2025. Axon Framework
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.