lizhimins commented on code in PR #342: URL: https://github.com/apache/rocketmq-clients/pull/342#discussion_r1124300049
########## java/client-apis/src/main/java/org/apache/rocketmq/client/apis/consumer/PullConsumer.java: ########## @@ -0,0 +1,136 @@ +/* + * 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.rocketmq.client.apis.consumer; + +import java.io.Closeable; +import java.io.IOException; +import java.time.Duration; +import java.util.Collection; +import java.util.List; +import java.util.Optional; +import org.apache.rocketmq.client.apis.ClientException; +import org.apache.rocketmq.client.apis.message.MessageQueue; +import org.apache.rocketmq.client.apis.message.MessageView; + +public interface PullConsumer extends Closeable { + /** + * Get the consumer group of the consumer. + */ + String getConsumerGroup(); + + /** + * @param topic the topic that needs to be monitored. + * @param listener the callback to detect the message queue changes. + */ + void registerMessageQueueChangeListenerByTopic(String topic, TopicMessageQueueChangeListener listener); + + /** + * Fetch message queues of the topic. + */ + Collection<MessageQueue> fetchMessageQueues(String topic) throws ClientException; + + /** + * Manually assign a list of message queues to this consumer. + * + * <p>This interface does not allow for incremental assignment and will replace the previous assignment (if + * previous assignment existed). + * + * @param messageQueues the list of message queues that are to be assigned to this consumer. + */ + void assign(Collection<MessageQueue> messageQueues); + + /** + * Fetch messages from assigned message queues specified by {@link #assign(Collection)}. + * + * <p>The messages polled from remote are across the message queue. + * + * @param timeout the maximum time to block. + * @return list of fetched messages. + */ + List<MessageView> poll(Duration timeout); + + /** + * Overrides the fetch offsets that the consumer will use on the next poll. If this method is invoked for the same + * message queue more than once, the latest offset will be used on the next {@link #poll(Duration)}. + * + * @param messageQueue the message queue to override the fetch offset. + * @param offset message offset. + */ + void seek(MessageQueue messageQueue, long offset); + + /** + * Suspending message pulling from the message queues. + * + * @param messageQueues message queues that need to be suspended. + */ + void pause(Collection<MessageQueue> messageQueues); + + /** + * Resuming message pulling from the message queues. + * + * @param messageQueues message queues that need to be resumed. + */ + void resume(Collection<MessageQueue> messageQueues); + + /** + * Look up the offsets for the given message queue by timestamp. The returned offset for each message queue is the + * earliest offset whose timestamp is greater than or equal to the given timestamp in the corresponding message + * queue. + * + * @param messageQueue message queue that needs to be looked up. + * @param timestamp the timestamp for which to search. + * @return the offset of the message queue, or {@link Optional#empty()} if there is no message. + */ + Optional<Long> offsetForTimestamp(MessageQueue messageQueue, Long timestamp); + + /** + * Get the latest committed offset for the given message queue. + * + * @return the latest committed offset, or {@link Optional#empty()} if there was no prior commit. + */ + Optional<Long> committed(MessageQueue messageQueue); + + /** + * Commit offset manually. + */ + void commit() throws ClientException; Review Comment: The semantics of commit are unclear, for example, for a single queue client, the pull progress is 200, and the poll function returns 100 at this time, we don't know the consumption progress. If we commit 200 will lose the message, commit 100 is not correct either. For users, it is not the case that the previous batch of messages needs to be consumed before taking the next batch. So the meaning here is auto commit. For stream frameworks, it is usually expected that commit and ckpt are atomic, and I think commit(mq, offset) should also be added as a manual interface. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
