org.apache.flink.streaming.api.functions.windowing

Class FoldWindowFunction<K,W extends Window,T,R>

java.lang.Object

org.apache.flink.api.common.functions.AbstractRichFunction

org.apache.flink.api.java.operators.translation.WrappingFunction<FoldFunction<T,R>>

org.apache.flink.streaming.api.functions.windowing.FoldWindowFunction<K,W,T,R>

All Implemented Interfaces:

Serializable, Function, RichFunction, WindowFunction<T,R,K,W>, OutputTypeConfigurable<R>

public class FoldWindowFunction<K,W extends Window,T,R>
extends org.apache.flink.api.java.operators.translation.WrappingFunction<FoldFunction<T,R>>
implements WindowFunction<T,R,K,W>, OutputTypeConfigurable<R>

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.flink.api.java.operators.translation.WrappingFunction

wrappedFunction

Constructor Summary

Constructors

Constructor and Description
FoldWindowFunction(R initialValue, FoldFunction<T,R> reduceFunction)

Method Summary

Methods

Modifier and Type	Method and Description
void	apply(K k, W window, Iterable<T> values, Collector<R> out) Evaluates the window and outputs none or several elements.
void	setOutputType(TypeInformation<R> outTypeInfo, ExecutionConfig executionConfig) Is called by the StreamGraph.addOperator(Integer, StreamOperator, TypeInformation, TypeInformation, String) method when the StreamGraph is generated.

Methods inherited from class org.apache.flink.api.java.operators.translation.WrappingFunction

close, getWrappedFunction, open, setRuntimeContext

Methods inherited from class org.apache.flink.api.common.functions.AbstractRichFunction

getIterationRuntimeContext, getRuntimeContext

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FoldWindowFunction

public FoldWindowFunction(R initialValue,
                  FoldFunction<T,R> reduceFunction)

Method Detail

apply

public void apply(K k,
         W window,
         Iterable<T> values,
         Collector<R> out)
           throws Exception

Description copied from interface: WindowFunction

Evaluates the window and outputs none or several elements.

Specified by:

apply in interface WindowFunction<T,R,K,W extends Window>

Parameters:

k - The key for which this window is evaluated.

window - The window that is being evaluated.

values - The elements in the window being evaluated.

out - A collector for emitting elements.

Throws:

Exception - The function may throw exceptions to fail the program and trigger recovery.

setOutputType

public void setOutputType(TypeInformation<R> outTypeInfo,
                 ExecutionConfig executionConfig)

Description copied from interface: OutputTypeConfigurable

Is called by the StreamGraph.addOperator(Integer, StreamOperator, TypeInformation, TypeInformation, String) method when the StreamGraph is generated. The method is called with the output TypeInformation which is also used for the StreamTask output serializer.

Specified by:

setOutputType in interface OutputTypeConfigurable<R>

Parameters:

outTypeInfo - Output type information of the StreamTask

executionConfig - Execution configuration