org.apache.flink.streaming.api.datastream

Class DiscretizedStream<OUT>

java.lang.Object

org.apache.flink.streaming.api.datastream.WindowedDataStream<OUT>

org.apache.flink.streaming.api.datastream.DiscretizedStream<OUT>

Type Parameters:

OUT - The output type of the DiscretizedStream

public class DiscretizedStream<OUT>
extends WindowedDataStream<OUT>

A DiscretizedStream represents a data stream that has been divided into windows (predefined chunks). User defined function such as reduceWindow(ReduceFunction), mapWindow(WindowMapFunction), or aggregations can be applied to the windows.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	isPartitioned

Fields inherited from class org.apache.flink.streaming.api.datastream.WindowedDataStream

dataStream, discretizerKey, evictionHelper, groupByKey, isLocal, triggerHelper, userEvicter, userTrigger

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DiscretizedStream(SingleOutputStreamOperator<StreamWindow<OUT>,?> discretizedStream, org.apache.flink.api.java.functions.KeySelector<OUT,?> groupByKey, WindowUtils.WindowTransformation tranformation, boolean isPartitioned)

Method Summary

Modifier and Type	Method and Description
protected DiscretizedStream<OUT>	copy()
DataStream<OUT>	flatten() Flattens the results of the window computations and streams out the window elements.
<R> DiscretizedStream<R>	foldWindow(R initialValue, org.apache.flink.api.common.functions.FoldFunction<OUT,R> foldFunction, org.apache.flink.api.common.typeinfo.TypeInformation<R> outType) Applies a fold transformation on the windowed data stream by folding the current window at every trigger.The user can also extend the RichFoldFunction to gain access to other features provided by the RichFunction interface.
protected Class<?>	getClassAtPos(int pos)
DataStream<StreamWindow<OUT>>	getDiscretizedStream() Returns the DataStream of StreamWindows which represent the discretised stream.
org.apache.flink.api.common.ExecutionConfig	getExecutionConfig()
String	getName() Gets the name of the current data stream.
org.apache.flink.api.common.typeinfo.TypeInformation<OUT>	getType() Gets the output type.
WindowedDataStream<OUT>	local() Sets the window discretisation local, meaning that windows will be created in parallel at environment parallelism.
<R> DiscretizedStream<R>	mapWindow(WindowMapFunction<OUT,R> windowMapFunction) Applies a mapWindow transformation on the windowed data stream by calling the mapWindow function on the window at every trigger.
<R> DiscretizedStream<R>	mapWindow(WindowMapFunction<OUT,R> windowMapFunction, org.apache.flink.api.common.typeinfo.TypeInformation<R> returnType) Applies a mapWindow transformation on the windowed data stream by calling the mapWindow function on the window at every trigger.
DiscretizedStream<OUT>	name(String name) Sets the name of the current data stream.
DiscretizedStream<OUT>	reduceWindow(org.apache.flink.api.common.functions.ReduceFunction<OUT> reduceFunction) Applies a reduce transformation on the windowed data stream by reducing the current window at every trigger.The user can also extend the RichReduceFunction to gain access to other features provided by the RichFunction interface.
protected DiscretizedStream<OUT>	timeReduce(org.apache.flink.api.common.functions.ReduceFunction<OUT> reduceFunction) This method implements the parallel time reduce logic for time windows

Methods inherited from class org.apache.flink.streaming.api.datastream.WindowedDataStream

clean, every, foldWindow, getEviction, getTrigger, groupBy, groupBy, groupBy, isGrouped, max, max, maxBy, maxBy, maxBy, maxBy, min, min, minBy, minBy, minBy, minBy, sum, sum

Methods inherited from class java.lang.Object

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

Field Detail

isPartitioned

protected boolean isPartitioned

Constructor Detail

DiscretizedStream

protected DiscretizedStream(SingleOutputStreamOperator<StreamWindow<OUT>,?> discretizedStream,
                            org.apache.flink.api.java.functions.KeySelector<OUT,?> groupByKey,
                            WindowUtils.WindowTransformation tranformation,
                            boolean isPartitioned)

Method Detail

getName

public String getName()

Gets the name of the current data stream. This name is used by the visualization and logging during runtime.

Returns:

Name of the stream.

name

public DiscretizedStream<OUT> name(String name)

Sets the name of the current data stream. This name is used by the visualization and logging during runtime.

Returns:

The named operator.

flatten

public DataStream<OUT> flatten()

Description copied from class: WindowedDataStream

Flattens the results of the window computations and streams out the window elements.

Overrides:

flatten in class WindowedDataStream<OUT>

Returns:

The data stream consisting of the individual records.

getDiscretizedStream

public DataStream<StreamWindow<OUT>> getDiscretizedStream()

Description copied from class: WindowedDataStream

Returns the DataStream of StreamWindows which represent the discretised stream. There is no ordering guarantee for the received windows.

Overrides:

getDiscretizedStream in class WindowedDataStream<OUT>

Returns:

The discretised stream

reduceWindow

public DiscretizedStream<OUT> reduceWindow(org.apache.flink.api.common.functions.ReduceFunction<OUT> reduceFunction)

Description copied from class: WindowedDataStream

Applies a reduce transformation on the windowed data stream by reducing the current window at every trigger.The user can also extend the RichReduceFunction to gain access to other features provided by the RichFunction interface.

Overrides:

reduceWindow in class WindowedDataStream<OUT>

Parameters:

reduceFunction - The reduce function that will be applied to the windows.

Returns:

The transformed DataStream

timeReduce

protected DiscretizedStream<OUT> timeReduce(org.apache.flink.api.common.functions.ReduceFunction<OUT> reduceFunction)

This method implements the parallel time reduce logic for time windows

Overrides:

timeReduce in class WindowedDataStream<OUT>

Parameters:

reduceFunction - The reduce function to be applied on the windows

Returns:

The reduced DataStream

mapWindow

public <R> DiscretizedStream<R> mapWindow(WindowMapFunction<OUT,R> windowMapFunction)

Description copied from class: WindowedDataStream

Applies a mapWindow transformation on the windowed data stream by calling the mapWindow function on the window at every trigger. In contrast with the standard binary reducer, with mapWindow allows the user to access all elements of the window at the same time through the iterable interface. The user can also extend the RichWindowMapFunction to gain access to other features provided by the RichFunction interface.

Overrides:

mapWindow in class WindowedDataStream<OUT>

Parameters:

windowMapFunction - The function that will be applied to the windows.

Returns:

The transformed DataStream

mapWindow

public <R> DiscretizedStream<R> mapWindow(WindowMapFunction<OUT,R> windowMapFunction,
                                          org.apache.flink.api.common.typeinfo.TypeInformation<R> returnType)

Description copied from class: WindowedDataStream

Applies a mapWindow transformation on the windowed data stream by calling the mapWindow function on the window at every trigger. In contrast with the standard binary reducer, with mapWindow allows the user to access all elements of the window at the same time through the iterable interface. The user can also extend the RichWindowMapFunction to gain access to other features provided by the RichFunction interface.

This version of mapWindow uses user supplied typeinformation for serializaton. Use this only when the system is unable to detect type information.

Overrides:

mapWindow in class WindowedDataStream<OUT>

Parameters:

windowMapFunction - The function that will be applied to the windows.

returnType - The output type of the operator.

Returns:

The transformed DataStream

foldWindow

public <R> DiscretizedStream<R> foldWindow(R initialValue,
                                           org.apache.flink.api.common.functions.FoldFunction<OUT,R> foldFunction,
                                           org.apache.flink.api.common.typeinfo.TypeInformation<R> outType)

Description copied from class: WindowedDataStream

Applies a fold transformation on the windowed data stream by folding the current window at every trigger.The user can also extend the RichFoldFunction to gain access to other features provided by the RichFunction interface. This version of foldWindow uses user supplied typeinformation for serializaton. Use this only when the system is unable to detect type information.

Overrides:

foldWindow in class WindowedDataStream<OUT>

Parameters:

initialValue - Initial value given to foldFunction

foldFunction - The fold function that will be applied to the windows.

outType - The output type of the operator

Returns:

The transformed DataStream

getClassAtPos

protected Class<?> getClassAtPos(int pos)

Overrides:

getClassAtPos in class WindowedDataStream<OUT>

getExecutionConfig

public org.apache.flink.api.common.ExecutionConfig getExecutionConfig()

Overrides:

getExecutionConfig in class WindowedDataStream<OUT>

getType

public org.apache.flink.api.common.typeinfo.TypeInformation<OUT> getType()

Gets the output type.

Overrides:

getType in class WindowedDataStream<OUT>

Returns:

The output type.

copy

protected DiscretizedStream<OUT> copy()

Overrides:

copy in class WindowedDataStream<OUT>

local

public WindowedDataStream<OUT> local()

Description copied from class: WindowedDataStream

Sets the window discretisation local, meaning that windows will be created in parallel at environment parallelism.

Overrides:

local in class WindowedDataStream<OUT>

Returns:

The WindowedDataStream with local discretisation