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

Class SlidingWindows

java.lang.Object

com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn<T,W>

com.google.cloud.dataflow.sdk.transforms.windowing.NonMergingWindowFn<Object,IntervalWindow>

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

All Implemented Interfaces:

Serializable

public class SlidingWindows
extends NonMergingWindowFn<Object,IntervalWindow>

A WindowFn that windows values into possibly overlapping fixed-size timestamp-based windows.

For example, in order to window data into 10 minute windows that update every minute:

 
 PCollection<Integer> items = ...;
 PCollection<Integer> windowedItems = items.apply(
   Window.<Integer>into(SlidingWindows.of(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

Modifier and Type	Method and Description
Collection<IntervalWindow>	assignWindows(WindowFn.AssignContext c) Given a timestamp and element, returns the set of windows into which it should be placed.
SlidingWindows	every(org.joda.time.Duration period) Returns a new SlidingWindows with the original size, that assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.
org.joda.time.Duration	getOffset()
org.joda.time.Instant	getOutputTime(org.joda.time.Instant inputTimestamp, IntervalWindow window) Ensure that later sliding windows have an output time that is past the end of earlier windows.
org.joda.time.Duration	getPeriod()
IntervalWindow	getSideInputWindow(BoundedWindow window) Return the earliest window that contains the end of the main-input window.
org.joda.time.Duration	getSize()
boolean	isCompatible(WindowFn<?,?> other) Returns whether this performs the same merging as the given WindowFn.
static SlidingWindows	of(org.joda.time.Duration size) Assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.
Coder<IntervalWindow>	windowCoder() Returns the Coder used for serializing the windows used by this windowFn.
SlidingWindows	withOffset(org.joda.time.Duration offset) Assigns timestamps into half-open intervals of the form [N * period + offset, N * period + offset + size).

Methods inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.NonMergingWindowFn

isNonMerging, mergeWindows

Methods inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn

assignsToSingleWindow

Methods inherited from class java.lang.Object

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

Method Detail

of

public static SlidingWindows of(org.joda.time.Duration size)

Assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.

If every(org.joda.time.Duration) is not called, the period defaults to the largest time unit smaller than the given duration. For example, specifying a size of 5 seconds will result in a default period of 1 second.

every

public SlidingWindows every(org.joda.time.Duration period)

Returns a new SlidingWindows with the original size, that assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.

withOffset

public SlidingWindows withOffset(org.joda.time.Duration offset)

Assigns timestamps into half-open intervals of the form [N * period + offset, N * period + offset + size).

Throws:

IllegalArgumentException - if offset is not in [0, period)

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<Object,IntervalWindow>

assignWindows

public 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<Object,IntervalWindow>

getSideInputWindow

public IntervalWindow getSideInputWindow(BoundedWindow window)

Return the earliest window that contains the end of the main-input window.

Specified by:

getSideInputWindow in class WindowFn<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<Object,IntervalWindow>

getPeriod

public org.joda.time.Duration getPeriod()

getSize

public org.joda.time.Duration getSize()

getOffset

public org.joda.time.Duration getOffset()

getOutputTime

public org.joda.time.Instant getOutputTime(org.joda.time.Instant inputTimestamp,
                                           IntervalWindow window)

Ensure that later sliding windows have an output time that is past the end of earlier windows.

If this is the earliest sliding window containing inputTimestamp, that's fine. Otherwise, we pick the earliest time that doesn't overlap with earlier windows.

Specified by:

getOutputTime in class WindowFn<Object,IntervalWindow>