raminqaf commented on code in PR #15601: URL: https://github.com/apache/kafka/pull/15601#discussion_r1600077088
########## streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoin.java: ########## @@ -43,7 +42,7 @@ import static org.apache.kafka.streams.StreamsConfig.InternalConfig.EMIT_INTERVAL_MS_KSTREAMS_OUTER_JOIN_SPURIOUS_RESULTS_FIX; import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor; -class KStreamKStreamJoin<K, V1, V2, VOut> implements ProcessorSupplier<K, V1, K, VOut> { +abstract class KStreamKStreamJoin<K, VL, VR, VOut, VThis, VOther> implements ProcessorSupplier<K, VThis, K, VOut> { Review Comment: We needed a way to detect the type of the side being called dynamically. So that the super class can handle them based on the caller. It also ensures the type safety. When this class is called by the _left side_ of the join `VThis` would be _left_ left type (`VLeft`) and `VOther` would be _right_ type (`VRight`). ```java class KStreamKStreamLeftJoinSide<K, VLeft, VRight, VOut> extends KStreamKStreamJoin<K, VLeft, VRight, VOut, VLeft, VRight> { --^-- --^--- VThis VOther ``` Whereas for the _right side_ of the join `VThis` would be _right_ left type (`VRight`) and `VOther` would be _left_ type (`VLeft`). ```java class KStreamKStreamRightJoinSide<K, VLeft, VRight, VOut> extends KStreamKStreamJoin<K, VLeft, VRight, VOut, VRight, VLeft> --^-- --^--- VThis VOther ``` ########## streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoin.java: ########## @@ -43,7 +42,7 @@ import static org.apache.kafka.streams.StreamsConfig.InternalConfig.EMIT_INTERVAL_MS_KSTREAMS_OUTER_JOIN_SPURIOUS_RESULTS_FIX; import static org.apache.kafka.streams.processor.internals.metrics.TaskMetrics.droppedRecordsSensor; -class KStreamKStreamJoin<K, V1, V2, VOut> implements ProcessorSupplier<K, V1, K, VOut> { +abstract class KStreamKStreamJoin<K, VL, VR, VOut, VThis, VOther> implements ProcessorSupplier<K, VThis, K, VOut> { Review Comment: We needed a way to detect the type of the side being called dynamically so that the super class can handle them based on the caller. This also ensures type safety. When this class is called by the _left side_ of the join `VThis` would be _left_ left type (`VLeft`) and `VOther` would be _right_ type (`VRight`). ```java class KStreamKStreamLeftJoinSide<K, VLeft, VRight, VOut> extends KStreamKStreamJoin<K, VLeft, VRight, VOut, VLeft, VRight> { --^-- --^--- VThis VOther ``` Whereas for the _right side_ of the join `VThis` would be _right_ left type (`VRight`) and `VOther` would be _left_ type (`VLeft`). ```java class KStreamKStreamRightJoinSide<K, VLeft, VRight, VOut> extends KStreamKStreamJoin<K, VLeft, VRight, VOut, VRight, VLeft> --^-- --^--- VThis VOther ``` -- 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: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org