org.apache.beam.sdk.transforms.windowing

Class PartitioningWindowFn<T,W extends BoundedWindow>

java.lang.Object

org.apache.beam.sdk.transforms.windowing.WindowFn<T,W>

org.apache.beam.sdk.transforms.windowing.NonMergingWindowFn<T,W>

org.apache.beam.sdk.transforms.windowing.PartitioningWindowFn<T,W>

Type Parameters:

T - type of elements being windowed

W - window type

All Implemented Interfaces:

java.io.Serializable, HasDisplayData

Direct Known Subclasses:

CalendarWindows.DaysWindows, CalendarWindows.MonthsWindows, CalendarWindows.YearsWindows, FixedWindows

public abstract class PartitioningWindowFn<T,W extends BoundedWindow>
extends NonMergingWindowFn<T,W>

A WindowFn that places each value into exactly one window based on its timestamp and never merges windows.

See Also:

Serialized Form

Nested Class Summary

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

WindowFn.AssignContext, WindowFn.MergeContext

Constructor Summary

Constructors

Constructor and Description
PartitioningWindowFn()

Method Summary

Modifier and Type	Method and Description
boolean	assignsToOneWindow() Returns true if this WindowFn always assigns an element to exactly one window.
abstract W	assignWindow(Instant timestamp) Returns the single window to which elements with this timestamp belong.
java.util.Collection<W>	assignWindows(WindowFn.AssignContext c) Given a timestamp and element, returns the set of windows into which it should be placed.
WindowMappingFn<W>	getDefaultWindowMappingFn() Returns the default WindowMappingFn to use to map main input windows to side input windows.
Instant	getOutputTime(Instant inputTimestamp, W window) Returns the output timestamp to use for data depending on the given inputTimestamp in the specified window.

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

isNonMerging, mergeWindows

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

getWindowTypeDescriptor, isCompatible, populateDisplayData, verifyCompatibility, windowCoder

Methods inherited from class java.lang.Object

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

Constructor Detail

PartitioningWindowFn

public PartitioningWindowFn()

Method Detail

assignWindow

public abstract W assignWindow(Instant timestamp)

Returns the single window to which elements with this timestamp belong.

assignWindows

public final java.util.Collection<W> 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<T,W extends BoundedWindow>

getDefaultWindowMappingFn

public WindowMappingFn<W> 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<T,W extends BoundedWindow>

getOutputTime

public Instant getOutputTime(Instant inputTimestamp,
                             W window)

Description copied from class: WindowFn

Returns the output timestamp to use for data depending on the given inputTimestamp in the specified window.

The result of this method must be between inputTimestamp and window.maxTimestamp() (inclusive on both sides).

This function must be monotonic across input timestamps. Specifically, if A < B, then getOutputTime(A, window) <= getOutputTime(B, window).

For a WindowFn that doesn't produce overlapping windows, this can (and typically should) just return inputTimestamp. In the presence of overlapping windows, it is suggested that the result in later overlapping windows is past the end of earlier windows so that the later windows don't prevent the watermark from progressing past the end of the earlier window.

Overrides:

getOutputTime in class WindowFn<T,W extends BoundedWindow>

assignsToOneWindow

public final boolean assignsToOneWindow()

Description copied from class: WindowFn

Returns true if this WindowFn always assigns an element to exactly one window.

If this varies per-element, or cannot be determined, conservatively return false.

By default, returns false.

Overrides:

assignsToOneWindow in class WindowFn<T,W extends BoundedWindow>