pnowojski commented on a change in pull request #11467: [FLINK-16317][operators] Provide support for watermarks, key selector and latency marker in MultipleInputStreamOperator URL: https://github.com/apache/flink/pull/11467#discussion_r397441916
########## File path: flink-streaming-java/src/main/java/org/apache/flink/streaming/api/transformations/KeyedMultipleInputTransformation.java ########## @@ -0,0 +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.flink.streaming.api.transformations; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.dag.Transformation; +import org.apache.flink.api.java.functions.KeySelector; +import org.apache.flink.streaming.api.operators.StreamOperatorFactory; + +import java.util.ArrayList; +import java.util.List; + +/** + * {@link AbstractMultipleInputTransformation} implementation for keyed streams. + */ +@Internal +public class KeyedMultipleInputTransformation<OUT> extends AbstractMultipleInputTransformation<OUT> { Review comment: Ok, I remember the real reason why I introduced `Abstract` - keyed and non-keyed have different `addInput` methods, with different signature. If we make `KeyedMultipleInputTransformation extends MultipleInputTransformation`, we would drop compile time checks for correct `addInput` method calls, which is the main reason why there are two classes in the first place. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services