org.apache.flink.api.common.functions

Interface MapFunction<T,O>

Type Parameters:

T - Type of the input elements.

O - Type of the returned elements.

All Superinterfaces:

Function, Serializable

All Known Implementing Classes:

ArtificalOperatorStateMapper, ArtificialKeyedStateMapper, BlockingIncrementingMapFunction, ConnectedComponents.DuplicateValue, CsvTableSink.CsvFormatter, EnumTriangles.TupleEdgeConverter, FailureMapper, FormattingMapper, IterateExample.InputMap, IterateExample.OutputMap, KeyExtractingMapper, KeyRemovingMapper, KMeans.CentroidAverager, KMeans.CountAppender, KMeans.SelectNearestCenter, PaddingLeftMapFunction, PaddingRightMapFunction, PageRank.Dampener, PageRank.RankAssigner, PiEstimation.Sampler, RemoveRangeIndex, RemoveTimestampMapFunction, RichMapFunction, RollingAdditionMapper, StatefulStreamingJob.MyStatefulFunction, StreamSQLTestProgram.KillMapper, TwoKeyExtractingMapper

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@Public
 @FunctionalInterface
public interface MapFunction<T,O>
extends Function, Serializable

Base interface for Map functions. Map functions take elements and transform them, element wise. A Map function always produces a single result element for each input element. Typical applications are parsing elements, converting data types, or projecting out fields. Operations that produce multiple result elements from a single input element can be implemented using the FlatMapFunction.

The basic syntax for using a MapFunction is as follows:

 DataSet<X> input = ...;

 DataSet<Y> result = input.map(new MyMapFunction());
 

Method Summary

Modifier and Type	Method and Description
O	map(T value) The mapping method.

Method Detail

map

O map(T value)
throws Exception

The mapping method. Takes an element from the input data set and transforms it into exactly one element.

Parameters:

value - The input value.

Returns:

The transformed value

Throws:

Exception - This method may throw exceptions. Throwing an exception will cause the operation to fail and may trigger recovery.