org.apache.beam.sdk.transforms.windowing

Class Sessions

java.lang.Object

org.apache.beam.sdk.transforms.windowing.WindowFn<java.lang.Object,IntervalWindow>

org.apache.beam.sdk.transforms.windowing.Sessions

All Implemented Interfaces:

java.io.Serializable, HasDisplayData

public class Sessions
extends WindowFn<java.lang.Object,IntervalWindow>

A WindowFn that windows values into sessions separated by periods with no input for at least the duration specified by getGapDuration().

For example, in order to window data into session with at least 10 minute gaps in between them:

 PCollection<Integer> pc = ...;
 PCollection<Integer> windowed_pc = pc.apply(
   Window.<Integer>into(Sessions.withGapDuration(Duration.standardMinutes(10))));
 

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.beam.sdk.transforms.windowing.WindowFn

WindowFn.AssignContext, WindowFn.MergeContext

Method Summary

Modifier and Type	Method and Description
java.util.Collection<IntervalWindow>	assignWindows(WindowFn.AssignContext c) Given a timestamp and element, returns the set of windows into which it should be placed.
boolean	equals(java.lang.Object object)
WindowMappingFn<IntervalWindow>	getDefaultWindowMappingFn() Returns the default WindowMappingFn to use to map main input windows to side input windows.
Duration	getGapDuration()
TypeDescriptor<IntervalWindow>	getWindowTypeDescriptor() Returns a TypeDescriptor capturing what is known statically about the window type of this WindowFn instance's most-derived class.
int	hashCode()
boolean	isCompatible(WindowFn<?,?> other) Returns whether this performs the same merging as the given WindowFn.
void	mergeWindows(WindowFn.MergeContext c) Does whatever merging of windows is necessary.
void	populateDisplayData(DisplayData.Builder builder) Register display data for the given transform or component.
void	verifyCompatibility(WindowFn<?,?> other) Throw IncompatibleWindowException if this WindowFn does not perform the same merging as the given $WindowFn.
Coder<IntervalWindow>	windowCoder() Returns the Coder used for serializing the windows used by this windowFn.
static Sessions	withGapDuration(Duration gapDuration) Creates a Sessions WindowFn with the specified gap duration.

Methods inherited from class org.apache.beam.sdk.transforms.windowing.WindowFn

assignsToOneWindow, getOutputTime, isNonMerging

Methods inherited from class java.lang.Object

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

Method Detail

withGapDuration

public static Sessions withGapDuration(Duration gapDuration)

Creates a Sessions WindowFn with the specified gap duration.

assignWindows

public java.util.Collection<IntervalWindow> assignWindows(WindowFn.AssignContext c)

Description copied from class: WindowFn

Given a timestamp and element, returns the set of windows into which it should be placed.

Specified by:

assignWindows in class WindowFn<java.lang.Object,IntervalWindow>

mergeWindows

public void mergeWindows(WindowFn.MergeContext c)
                  throws java.lang.Exception

Description copied from class: WindowFn

Does whatever merging of windows is necessary.

See MergeOverlappingIntervalWindows.mergeWindows(org.apache.beam.sdk.transforms.windowing.WindowFn<?, org.apache.beam.sdk.transforms.windowing.IntervalWindow>.MergeContext) for an example of how to override this method.

Specified by:

mergeWindows in class WindowFn<java.lang.Object,IntervalWindow>

Throws:

java.lang.Exception

windowCoder

public Coder<IntervalWindow> windowCoder()

Description copied from class: WindowFn

Returns the Coder used for serializing the windows used by this windowFn.

Specified by:

windowCoder in class WindowFn<java.lang.Object,IntervalWindow>

isCompatible

public boolean isCompatible(WindowFn<?,?> other)

Description copied from class: WindowFn

Returns whether this performs the same merging as the given WindowFn.

Specified by:

isCompatible in class WindowFn<java.lang.Object,IntervalWindow>

verifyCompatibility

public void verifyCompatibility(WindowFn<?,?> other)
                         throws IncompatibleWindowException

Description copied from class: WindowFn

Throw IncompatibleWindowException if this WindowFn does not perform the same merging as the given $WindowFn.

Overrides:

verifyCompatibility in class WindowFn<java.lang.Object,IntervalWindow>

Throws:

IncompatibleWindowException - if compared WindowFns are not compatible.

getWindowTypeDescriptor

public TypeDescriptor<IntervalWindow> getWindowTypeDescriptor()

Description copied from class: WindowFn

Returns a TypeDescriptor capturing what is known statically about the window type of this WindowFn instance's most-derived class.

In the normal case of a concrete WindowFn subclass with no generic type parameters of its own (including anonymous inner classes), this will be a complete non-generic type.

Overrides:

getWindowTypeDescriptor in class WindowFn<java.lang.Object,IntervalWindow>

getDefaultWindowMappingFn

public WindowMappingFn<IntervalWindow> getDefaultWindowMappingFn()

Description copied from class: WindowFn

Returns the default WindowMappingFn to use to map main input windows to side input windows. This should accept arbitrary main input windows, and produce a BoundedWindow that can be produced by this WindowFn.

Specified by:

getDefaultWindowMappingFn in class WindowFn<java.lang.Object,IntervalWindow>

getGapDuration

public Duration getGapDuration()

populateDisplayData

public void populateDisplayData(DisplayData.Builder builder)

Description copied from class: WindowFn

Register display data for the given transform or component.

populateDisplayData(DisplayData.Builder) is invoked by Pipeline runners to collect display data via DisplayData.from(HasDisplayData). Implementations may call super.populateDisplayData(builder) in order to register display data in the current namespace, but should otherwise use subcomponent.populateDisplayData(builder) to use the namespace of the subcomponent.

By default, does not register any display data. Implementors may override this method to provide their own display data.

Specified by:

populateDisplayData in interface HasDisplayData

Overrides:

populateDisplayData in class WindowFn<java.lang.Object,IntervalWindow>

Parameters:

builder - The builder to populate with display data.

See Also:

HasDisplayData

equals

public boolean equals(java.lang.Object object)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object