com.google.cloud.dataflow.sdk.transforms.windowing

Class Sessions

java.lang.Object

com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn<java.lang.Object,IntervalWindow>

com.google.cloud.dataflow.sdk.transforms.windowing.Sessions

All Implemented Interfaces:

java.io.Serializable

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

A WindowFn windowing values into sessions separated by gapDuration-long periods with no elements.

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>by(Sessions.withGapDuration(Duration.standardMinutes(10))));
  

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn

WindowFn.AssignContext, WindowFn.MergeContext

Method Summary

Methods

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	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.
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 com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn

getSideInputWindow

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, 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(com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn<?, com.google.cloud.dataflow.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>