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

Class PartitioningWindowFn<T,W extends BoundedWindow>

java.lang.Object

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

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

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

Type Parameters:

T - type of elements being windowed

W - window type

All Implemented Interfaces:

Serializable

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

WindowFn.AssignContext, WindowFn.MergeContext

Constructor Summary

Constructors

Constructor and Description
PartitioningWindowFn()

Method Summary

Modifier and Type	Method and Description
boolean	assignsToSingleWindow() Returns true if this WindowFn assigns each element to a single window.
abstract W	assignWindow(org.joda.time.Instant timestamp) Returns the single window to which elements with this timestamp belong.
Collection<W>	assignWindows(WindowFn.AssignContext c) Given a timestamp and element, returns the set of windows into which it should be placed.
org.joda.time.Instant	getOutputTime(org.joda.time.Instant inputTimestamp, W window) Returns the output timestamp to use for data depending on the given inputTimestamp in the specified window.
W	getSideInputWindow(BoundedWindow window) Returns the window of the side input corresponding to the given window of the main input.

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

isCompatible, 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(org.joda.time.Instant timestamp)

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

assignWindows

public final 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>

getSideInputWindow

public W getSideInputWindow(BoundedWindow window)

Description copied from class: WindowFn

Returns the window of the side input corresponding to the given window of the main input.

Authors of custom WindowFns should override this.

Specified by:

getSideInputWindow in class WindowFn<T,W extends BoundedWindow>

assignsToSingleWindow

public boolean assignsToSingleWindow()

Description copied from class: WindowFn

Returns true if this WindowFn assigns each element to a single window.

Overrides:

assignsToSingleWindow in class WindowFn<T,W extends BoundedWindow>

getOutputTime

public org.joda.time.Instant getOutputTime(org.joda.time.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 must be between inputTimestamp and window.maxTimestamp() (inclusive on both sides). If this WindowFn doesn't produce overlapping windows, this can (and typically should) just return inputTimestamp. If this does produce 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.

Each KV<K, Iterable<V>> produced from a GroupByKey will be output at a timestamp that is the minimum of getOutputTime applied to the timestamp of all of the non-late KV<K, V> that were used as input to the GroupByKey. The watermark is also prevented from advancing past this minimum timestamp until after the KV<K, Iterable<V>> has been output.

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

Specified by:

getOutputTime in class WindowFn<T,W extends BoundedWindow>