Package org.apache.beam.sdk.transforms.windowing

Class BoundedWindow

java.lang.Object

org.apache.beam.sdk.transforms.windowing.BoundedWindow

Direct Known Subclasses:

EncodedBoundedWindow, GlobalWindow, IntervalWindow

public abstract class BoundedWindow
extends Object

A BoundedWindow represents window information assigned to data elements.

It has one method maxTimestamp() to define an upper bound (inclusive) for element timestamps. A WindowFn must assign an element only to windows where maxTimestamp() is greater than or equal to the element timestamp. When the watermark passes the maximum timestamp, all data for a window is estimated to be received.

A window does not need to have a lower bound. Only the upper bound is mandatory because it governs management of triggering and discarding of the window.

Windows must also implement Object.equals(java.lang.Object) and Object.hashCode() such that windows that are logically equal will be treated as equal by equals() and hashCode().

Field Summary

Fields

Modifier and Type	Field	Description
static final Instant	TIMESTAMP_MAX_VALUE	The maximum value for any Beam timestamp.
static final Instant	TIMESTAMP_MIN_VALUE	The minimum value for any Beam timestamp.

Constructor Summary

Constructors

Constructor	Description
BoundedWindow()

Method Summary

Modifier and Type	Method	Description
static String	formatTimestamp(Instant timestamp)	Formats a Instant timestamp with additional Beam-specific metadata, such as indicating whether the timestamp is the end of the global window or one of the distinguished values TIMESTAMP_MIN_VALUE or TIMESTAMP_MIN_VALUE.
abstract Instant	maxTimestamp()	Returns the inclusive upper bound of timestamps for values in this window.
static void	validateTimestampBounds(Instant timestamp)	Validates that a given timestamp is within min and max bounds.

Methods inherited from class java.lang.Object

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

Field Details

TIMESTAMP_MIN_VALUE

public static final Instant TIMESTAMP_MIN_VALUE

The minimum value for any Beam timestamp. Often referred to as "-infinity".

This value and TIMESTAMP_MAX_VALUE are chosen so that their microseconds-since-epoch can be safely represented with a long.

TIMESTAMP_MAX_VALUE

public static final Instant TIMESTAMP_MAX_VALUE

The maximum value for any Beam timestamp. Often referred to as "+infinity".

This value and TIMESTAMP_MIN_VALUE are chosen so that their microseconds-since-epoch can be safely represented with a long.

Constructor Details

BoundedWindow

public BoundedWindow()

Method Details

formatTimestamp

public static String formatTimestamp(Instant timestamp)

Formats a Instant timestamp with additional Beam-specific metadata, such as indicating whether the timestamp is the end of the global window or one of the distinguished values TIMESTAMP_MIN_VALUE or TIMESTAMP_MIN_VALUE.

maxTimestamp

public abstract Instant maxTimestamp()

Returns the inclusive upper bound of timestamps for values in this window.

validateTimestampBounds

public static void validateTimestampBounds(Instant timestamp)

Validates that a given timestamp is within min and max bounds.

Parameters:

timestamp - timestamp to validate