Samrat002 commented on code in PR #6: URL: https://github.com/apache/flink-connector-redis-streams/pull/6#discussion_r3178578675
########## flink-connector-redis-streams/src/main/java/org/apache/flink/connector/redis/streams/source/reader/RedisStreamsRecordEmitter.java: ########## @@ -0,0 +1,68 @@ +/* + * 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.flink.connector.redis.streams.source.reader; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.connector.source.SourceOutput; +import org.apache.flink.connector.base.source.reader.RecordEmitter; +import org.apache.flink.connector.redis.streams.source.RedisStreamsDeserializationSchema; +import org.apache.flink.connector.redis.streams.source.split.RedisStreamsSourceSplitState; + +import io.lettuce.core.StreamMessage; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** Record emitter that deserializes Redis StreamMessages. */ +@Internal +public class RedisStreamsRecordEmitter<T> + implements RecordEmitter<StreamMessage<String, String>, T, RedisStreamsSourceSplitState> { + + private static final Logger LOG = LoggerFactory.getLogger(RedisStreamsRecordEmitter.class); + + private final RedisStreamsDeserializationSchema<T> deserializationSchema; + + public RedisStreamsRecordEmitter(RedisStreamsDeserializationSchema<T> deserializationSchema) { + this.deserializationSchema = deserializationSchema; + } + + @Override + public void emitRecord( + StreamMessage<String, String> element, + SourceOutput<T> output, + RedisStreamsSourceSplitState splitState) + throws Exception { + try { + T record = + deserializationSchema.deserialize( + element.getStream(), element.getId(), element.getBody()); + // Null records are filter results, not failures, and must still be + // ACKed so they don't grow the PEL forever. + splitState.setCurrentEntryId(element.getId()); + if (record != null) { Review Comment: The Collector<T> pattern (as Kafka uses) is cleaner. It eliminates the need for null checks and lets users emit zero, one, or many records naturally. However, switching to Collector<T> is a breaking API change and significantly increases the complexity of the interface and the emitter. The null = drop contract is simple to understand, well-documented on the interface, and sufficient for all common filter patterns. I'd like to consider the Collector<T> approach for a future API revision, which would also allow us to revisit the broader schema design. -- 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]
