org.apache.beam.sdk.transforms.windowing

Class Window.Bound<T>

java.lang.Object

org.apache.beam.sdk.transforms.PTransform<PCollection<T>,PCollection<T>>

org.apache.beam.sdk.transforms.windowing.Window.Bound<T>

Type Parameters:

T - The type of elements this Window is applied to

All Implemented Interfaces:

Serializable, HasDisplayData

Enclosing class:

Window

public static class Window.Bound<T>
extends PTransform<PCollection<T>,PCollection<T>>

A PTransform that windows the elements of a PCollection<T>, into finite windows according to a user-specified WindowFn.

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.PTransform

name

Method Summary

Modifier and Type	Method and Description
Window.Bound<T>	accumulatingFiredPanes() Returns a new Window PTransform that uses the registered WindowFn and Triggering behavior, and that accumulates elements in a pane after they are triggered.
PCollection<T>	apply(PCollection<T> input) Applies this PTransform on the given InputT, and returns its Output.
Window.Bound<T>	discardingFiredPanes() Returns a new Window PTransform that uses the registered WindowFn and Triggering behavior, and that discards elements in a pane after they are triggered.
protected Coder<?>	getDefaultOutputCoder(PCollection<T> input) Returns the default Coder to use for the output of this single-output PTransform when applied to the given input.
protected String	getKindString() Returns the name to use by default for this PTransform (not including the names of any enclosing PTransforms).
org.apache.beam.sdk.util.WindowingStrategy<?,?>	getOutputStrategyInternal(org.apache.beam.sdk.util.WindowingStrategy<?,?> inputStrategy) Get the output strategy of this Window PTransform.
WindowFn<? super T,?>	getWindowFn() Get the WindowFn of this Window PTransform.
void	populateDisplayData(DisplayData.Builder builder) Register display data for the given transform or component.
Window.Bound<T>	triggering(Trigger trigger) Sets a non-default trigger for this Window PTransform.
void	validate(PCollection<T> input) Called before invoking apply (which may be intercepted by the runner) to verify this transform is fully specified and applicable to the specified input.
Window.Bound<T>	withAllowedLateness(Duration allowedLateness) Override the amount of lateness allowed for data elements in the pipeline.
Window.Bound<T>	withAllowedLateness(Duration allowedLateness, Window.ClosingBehavior behavior) Override the amount of lateness allowed for data elements in the pipeline.
Window.Bound<T>	withOutputTimeFn(OutputTimeFn<?> outputTimeFn) (Experimental) Override the default OutputTimeFn, to control the output timestamp of values output from a GroupByKey operation.

Methods inherited from class org.apache.beam.sdk.transforms.PTransform

getDefaultOutputCoder, getDefaultOutputCoder, getName, toString

Methods inherited from class java.lang.Object

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

Method Detail

triggering

@Experimental(value=TRIGGER)
public Window.Bound<T> triggering(Trigger trigger)

Sets a non-default trigger for this Window PTransform. Elements that are assigned to a specific window will be output when the trigger fires.

Trigger has more details on the available triggers.

Must also specify allowed lateness using withAllowedLateness(org.joda.time.Duration) and accumulation mode using either discardingFiredPanes() or accumulatingFiredPanes().

discardingFiredPanes

@Experimental(value=TRIGGER)
public Window.Bound<T> discardingFiredPanes()

Returns a new Window PTransform that uses the registered WindowFn and Triggering behavior, and that discards elements in a pane after they are triggered.

Does not modify this transform. The resulting PTransform is sufficiently specified to be applied, but more properties can still be specified.

accumulatingFiredPanes

@Experimental(value=TRIGGER)
public Window.Bound<T> accumulatingFiredPanes()

Returns a new Window PTransform that uses the registered WindowFn and Triggering behavior, and that accumulates elements in a pane after they are triggered.

Does not modify this transform. The resulting PTransform is sufficiently specified to be applied, but more properties can still be specified.

withAllowedLateness

@Experimental(value=TRIGGER)
public Window.Bound<T> withAllowedLateness(Duration allowedLateness)

Override the amount of lateness allowed for data elements in the pipeline. Like the other properties on this Window operation, this will be applied at the next GroupByKey. Any elements that are later than this as decided by the system-maintained watermark will be dropped.

This value also determines how long state will be kept around for old windows. Once no elements will be added to a window (because this duration has passed) any state associated with the window will be cleaned up.

Depending on the trigger this may not produce a pane with PaneInfo.isLast. See Window.ClosingBehavior.FIRE_IF_NON_EMPTY for more details.

withOutputTimeFn

@Experimental(value=OUTPUT_TIME)
public Window.Bound<T> withOutputTimeFn(OutputTimeFn<?> outputTimeFn)

(Experimental) Override the default OutputTimeFn, to control the output timestamp of values output from a GroupByKey operation.

withAllowedLateness

@Experimental(value=TRIGGER)
public Window.Bound<T> withAllowedLateness(Duration allowedLateness,
                                                                        Window.ClosingBehavior behavior)

Override the amount of lateness allowed for data elements in the pipeline. Like the other properties on this Window operation, this will be applied at the next GroupByKey. Any elements that are later than this as decided by the system-maintained watermark will be dropped.

This value also determines how long state will be kept around for old windows. Once no elements will be added to a window (because this duration has passed) any state associated with the window will be cleaned up.

getOutputStrategyInternal

public org.apache.beam.sdk.util.WindowingStrategy<?,?> getOutputStrategyInternal(org.apache.beam.sdk.util.WindowingStrategy<?,?> inputStrategy)

Get the output strategy of this Window PTransform. For internal use only.

getWindowFn

public WindowFn<? super T,?> getWindowFn()

Get the WindowFn of this Window PTransform.

validate

public void validate(PCollection<T> input)

Description copied from class: PTransform

Called before invoking apply (which may be intercepted by the runner) to verify this transform is fully specified and applicable to the specified input.

By default, does nothing.

Overrides:

validate in class PTransform<PCollection<T>,PCollection<T>>

apply

public PCollection<T> apply(PCollection<T> input)

Description copied from class: PTransform

Applies this PTransform on the given InputT, and returns its Output.

Composite transforms, which are defined in terms of other transforms, should return the output of one of the composed transforms. Non-composite transforms, which do not apply any transforms internally, should return a new unbound output and register evaluators (via backend-specific registration methods).

Specified by:

apply in class PTransform<PCollection<T>,PCollection<T>>

populateDisplayData

public void populateDisplayData(DisplayData.Builder builder)

Description copied from class: PTransform

Register display data for the given transform or component.

populateDisplayData(DisplayData.Builder) is invoked by Pipeline runners to collect display data via DisplayData.from(HasDisplayData). Implementations may call super.populateDisplayData(builder) in order to register display data in the current namespace, but should otherwise use subcomponent.populateDisplayData(builder) to use the namespace of the subcomponent.

By default, does not register any display data. Implementors may override this method to provide their own display data.

Specified by:

populateDisplayData in interface HasDisplayData

Overrides:

populateDisplayData in class PTransform<PCollection<T>,PCollection<T>>

Parameters:

builder - The builder to populate with display data.

See Also:

HasDisplayData

getDefaultOutputCoder

protected Coder<?> getDefaultOutputCoder(PCollection<T> input)

Description copied from class: PTransform

Returns the default Coder to use for the output of this single-output PTransform when applied to the given input.

Overrides:

getDefaultOutputCoder in class PTransform<PCollection<T>,PCollection<T>>

getKindString

protected String getKindString()

Description copied from class: PTransform

Returns the name to use by default for this PTransform (not including the names of any enclosing PTransforms).

By default, returns the base name of this PTransform's class.

The caller is responsible for ensuring that names of applied PTransforms are unique, e.g., by adding a uniquifying suffix when needed.

Overrides:

getKindString in class PTransform<PCollection<T>,PCollection<T>>