jinxing64 commented on a change in pull request #1232: URL: https://github.com/apache/flink/pull/1232#discussion_r439315618
########## File path: flink-staging/flink-streaming/flink-streaming-core/src/main/java/org/apache/flink/streaming/api/datastream/CoGroupedStreams.java ########## @@ -0,0 +1,563 @@ +/* + * 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.datastream; + +import com.google.common.collect.Lists; +import org.apache.flink.api.common.ExecutionConfig; +import org.apache.flink.api.common.functions.CoGroupFunction; +import org.apache.flink.api.common.functions.MapFunction; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.api.java.functions.KeySelector; +import org.apache.flink.api.java.operators.translation.WrappingFunction; +import org.apache.flink.api.java.typeutils.TypeExtractor; +import org.apache.flink.core.memory.DataInputView; +import org.apache.flink.core.memory.DataOutputView; +import org.apache.flink.streaming.api.functions.windowing.WindowFunction; +import org.apache.flink.streaming.api.windowing.assigners.WindowAssigner; +import org.apache.flink.streaming.api.windowing.evictors.Evictor; +import org.apache.flink.streaming.api.windowing.triggers.Trigger; +import org.apache.flink.streaming.api.windowing.windows.Window; +import org.apache.flink.util.Collector; + +import java.io.IOException; +import java.util.List; + +/** + *{@code CoGroupedStreams} represents two {@link DataStream DataStreams} that have been co-grouped. + * A streaming co-group operation is evaluated over elements in a window. + * + * <p> + * To finalize co-group operation you also need to specify a {@link KeySelector} for + * both the first and second input and a {@link WindowAssigner}. + * + * <p> + * Note: Right now, the groups are being built in memory so you need to ensure that they don't + * get too big. Otherwise the JVM might crash. + * + * <p> + * Example: + * + * <pre> {@code + * DataStream<Tuple2<String, Integer>> one = ...; + * DataStream<Tuple2<String, Integer>> two = ...; + * + * DataStream<T> result = one.coGroup(two) + * .where(new MyFirstKeySelector()) + * .equalTo(new MyFirstKeySelector()) Review comment: Should it be MySecondKeySelector ? ---------------------------------------------------------------- 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: [email protected]
