/*
* 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.api.common.functions;
import org.apache.flink.annotation.Public;
import org.apache.flink.util.Collector;
import java.io.Serializable;
/**
* Interface for "mapPartition" functions. A "mapPartition" function is called a single time per
* data partition receives an Iterable with data elements of that partition. It may return an
* arbitrary number of data elements.
* <p>
* This function is intended to provide enhanced flexibility in the processing of elements in a partition.
* For most of the simple use cases, consider using the {@link MapFunction} or {@link FlatMapFunction}.
* <p>
* The basic syntax for a MapPartitionFunction is as follows:
* <pre>{@code
* DataSet<X> input = ...;
*
* DataSet<Y> result = input.mapPartition(new MyMapPartitionFunction());
* }</pre>
*
* @param <T> Type of the input elements.
* @param <O> Type of the returned elements.
*/
@Public
public interface MapPartitionFunction<T, O> extends Function, Serializable {
/**
* A user-implemented function that modifies or transforms an incoming object.
*
* @param values All records for the mapper
* @param out The collector to hand results to.
* @throws Exception
*/
void mapPartition(Iterable<T> values, Collector<O> out) throws Exception;
}