davidradl commented on code in PR #26328: URL: https://github.com/apache/flink/pull/26328#discussion_r2006021841
########## flink-runtime/src/main/java/org/apache/flink/runtime/asyncprocessing/functions/DeclaringAsyncKeyedCoProcessFunction.java: ########## @@ -0,0 +1,170 @@ +/* + * 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.runtime.asyncprocessing.functions; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.runtime.asyncprocessing.declare.DeclarationContext; +import org.apache.flink.runtime.asyncprocessing.declare.DeclarationException; +import org.apache.flink.streaming.api.TimeDomain; +import org.apache.flink.streaming.api.TimerService; +import org.apache.flink.streaming.api.functions.co.CoFlatMapFunction; +import org.apache.flink.streaming.api.functions.co.KeyedCoProcessFunction; +import org.apache.flink.util.Collector; +import org.apache.flink.util.function.ThrowingConsumer; + +/** + * A function that processes elements of two keyed streams and produces a single output one. + * + * <p>The function will be called for every element in the input streams and can produce zero or + * more output elements. Contrary to the {@link CoFlatMapFunction}, this function can also query the + * time (both event and processing) and set timers, through the provided {@link Context}. When + * reacting to the firing of set timers the function can emit yet more elements. + * + * <p>An example use-case for connected streams would be the application of a set of rules that + * change over time ({@code stream A}) to the elements contained in another stream (stream {@code + * B}). The rules contained in {@code stream A} can be stored in the state and wait for new elements + * to arrive on {@code stream B}. Upon reception of a new element on {@code stream B}, the function + * can now apply the previously stored rules to the element and directly emit a result, and/or + * register a timer that will trigger an action in the future. + * + * @param <K> Type of the key. + * @param <IN1> Type of the first input. + * @param <IN2> Type of the second input. + * @param <OUT> Output type. + */ +@Internal +public abstract class DeclaringAsyncKeyedCoProcessFunction<K, IN1, IN2, OUT> + extends KeyedCoProcessFunction<K, IN1, IN2, OUT> { + + private static final long serialVersionUID = 1L; + + /** + * This method is called for each element in the first of the connected streams. + * + * <p>This function can output zero or more elements using the {@link Collector} parameter and + * also update internal state or set timers using the {@link Context} parameter. + * + * @param value The stream element + * @param ctx A {@link Context} that allows querying the timestamp of the element, querying the Review Comment: nit: maybe a list would be easier to read in the javadoc. A {@link Context} that allows querying of <ol> ... </ol> When you say `querying the time` is this event or processing? -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
