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

Class Sessions

java.lang.Object

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

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

All Implemented Interfaces:

java.io.Serializable

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

A WindowingFn 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.WindowingFn

WindowingFn.AssignContext, WindowingFn.MergeContext

Method Summary

Methods

Modifier and Type	Method and Description
java.util.Collection<IntervalWindow>	assignWindows(WindowingFn.AssignContext c) Given a timestamp and element, returns the set of windows into which it should be placed.
boolean	isCompatible(WindowingFn<?,?> other) Returns whether this performs the same merging as the given WindowingFn.
void	mergeWindows(WindowingFn.MergeContext c) Does whatever merging of windows is necessary.
Coder<IntervalWindow>	windowCoder() Returns the Coder used for serializing the windows used by this windowingFn.
static Sessions	withGapDuration(Duration gapDuration) Creates a Sessions WindowingFn with the specified gap duration.

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 WindowingFn with the specified gap duration.

assignWindows

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

Description copied from class: WindowingFn

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

Specified by:

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

mergeWindows

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

Description copied from class: WindowingFn

Does whatever merging of windows is necessary.

See MergeOverlappingIntervalWindows.mergeWindows(com.google.cloud.dataflow.sdk.transforms.windowing.WindowingFn<?, com.google.cloud.dataflow.sdk.transforms.windowing.IntervalWindow>.MergeContext) for an example of how to override this method.

Specified by:

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

Throws:

java.lang.Exception

windowCoder

public Coder<IntervalWindow> windowCoder()

Description copied from class: WindowingFn

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

Specified by:

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

isCompatible

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

Description copied from class: WindowingFn

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

Specified by:

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