spark-gpu-master/core/src/main/java/org/apache/spark/api/java/function/CoGroupFunction.java
/*
 * 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.spark.api.java.function;

import java.io.Serializable;
import java.util.Iterator;

/**
 * A function that returns zero or more output records from each grouping key and its values from 2
 * Datasets.
 */
public interface CoGroupFunction<K, V1, V2, R> extends Serializable {
  Iterable<R> call(K key, Iterator<V1> left, Iterator<V2> right) throws Exception;
}
