Java tutorial
/* * 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; import org.apache.spark.annotation.Evolving; import org.apache.spark.annotation.Experimental; import org.apache.spark.sql.streaming.GroupState; /** * ::Experimental:: * Base interface for a map function used in * {@link org.apache.spark.sql.KeyValueGroupedDataset#mapGroupsWithState( * MapGroupsWithStateFunction, org.apache.spark.sql.Encoder, org.apache.spark.sql.Encoder)} * @since 2.1.1 */ @Experimental @Evolving public interface MapGroupsWithStateFunction<K, V, S, R> extends Serializable { R call(K key, Iterator<V> values, GroupState<S> state) throws Exception; }