com.google.cloud.dataflow.sdk.transforms.windowing (Google Cloud Dataflow SDK 1.2.1 API)

Interface Summary
Interface	Description
Trigger.MergingTriggerInfo<W extends BoundedWindow>	Interact with properties of the trigger being executed, with extensions to deal with the merging windows.
Trigger.TriggerInfo<W extends BoundedWindow>	Interface for accessing information about the trigger being executed and other triggers in the same tree.
TriggerBuilder<W extends BoundedWindow>	Anything that can be used to create an instance of a `Trigger` implements this interface.

Class Summary
Class	Description
AfterAll<W extends BoundedWindow>	Create a `Trigger` that fires and finishes once after all of its sub-triggers have fired.
AfterEach<W extends BoundedWindow>	A composite `Trigger` that executes its sub-triggers in order.
AfterFirst<W extends BoundedWindow>	Create a composite `Trigger` that fires once after at least one of its sub-triggers have fired.
AfterPane<W extends BoundedWindow>	`Trigger`s that fire based on properties of the elements in the current pane.
AfterProcessingTime<W extends BoundedWindow>	`AfterProcessingTime` triggers fire based on the current processing time.
AfterWatermark<W extends BoundedWindow>	`AfterWatermark` triggers fire based on progress of the system watermark.
BoundedWindow	A `BoundedWindow` represents a finite grouping of elements, with an upper bound (larger timestamps represent more recent data) on the timestamps of elements that can be placed in the window.
CalendarWindows	A collection of `WindowFn`s that windows values into calendar-based windows such as spans of days, months, or years.
CalendarWindows.DaysWindows	A `WindowFn` that windows elements into periods measured by days.
CalendarWindows.MonthsWindows	A `WindowFn` that windows elements into periods measured by months.
CalendarWindows.YearsWindows	A `WindowFn` that windows elements into periods measured by years.
DefaultTrigger<W extends BoundedWindow>	A trigger that is equivalent to `Repeatedly.forever(AfterWatermark.pastEndOfWindow())`.
FixedWindows	A `WindowFn` that windows values into fixed-size timestamp-based windows.
GlobalWindow	The default window into which all data is placed (via `GlobalWindows`).
GlobalWindow.Coder	`GlobalWindow.Coder` for encoding and decoding `Window`s.
GlobalWindows	Default `WindowFn` where all data is in the same window.
IntervalWindow	An implementation of `BoundedWindow` that represents an interval from `IntervalWindow.start` (inclusive) to `IntervalWindow.end` (exclusive).
InvalidWindows<W extends BoundedWindow>	A `WindowFn` that represents an invalid pipeline state.
MergeOverlappingIntervalWindows	A `WindowFn` that merges overlapping `IntervalWindow`s.
NonMergingWindowFn<T,W extends BoundedWindow>	Abstract base class for `WindowFn`s that do not merge windows.
PaneInfo	Provides information about the pane this value belongs to.
PaneInfo.PaneInfoCoder	A Coder for encoding PaneInfo instances.
PartitioningWindowFn<T,W extends BoundedWindow>	A `WindowFn` that places each value into exactly one window based on its timestamp and never merges windows.
Repeatedly<W extends BoundedWindow>	Repeat a trigger, either until some condition is met or forever.
Sessions	A `WindowFn` windowing values into sessions separated by `Sessions.gapDuration`-long periods with no elements.
SlidingWindows	A `WindowFn` that windows values into possibly overlapping fixed-size timestamp-based windows.
TimeTrigger<W extends BoundedWindow>	Support for manipulating the time at which time-based `Trigger`s fire.
Trigger<W extends BoundedWindow>	`Trigger`s control when the elements for a specific key and window are output.
Trigger.OnceTrigger<W extends BoundedWindow>	`Trigger`s that are guaranteed to fire at most once should extend from this, rather than the general `Trigger` class to indicate that behavior.
Window	`Window` logically divides up or groups the elements of a `PCollection` into finite windows according to a `WindowFn`.
Window.Bound<T>	A `PTransform` that windows the elements of a `PCollection<T>`, into finite windows according to a user-specified `WindowFn<T, B>`.
Window.Remerge<T>	`PTransform` that does not change assigned windows, but will cause windows to be merged again as part of the next `GroupByKey`.
Window.Unbound	An incomplete `Window` transform, with unbound input/output type.
WindowFn<T,W extends BoundedWindow>	The argument to the `Window` transform used to assign elements into windows and to determine how windows are merged.

Enum Summary
Enum	Description
PaneInfo.Timing	Enumerates the possibilities for how the timing of this pane firing related to the watermark.
Trigger.MergeResult	`TriggerResult` enumerates the possible result a trigger can have when it is merged.
Trigger.TriggerResult	`TriggerResult` enumerates the possible result a trigger can have when it is executed.
Window.ClosingBehavior	Specifies the conditions under which a final pane will be created when a window is permanently closed.

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

Defines the Window transform for dividing the elements in a PCollection into windows, and the Trigger for controlling when those elements are output.

Window logically divides up or groups the elements of a PCollection into finite windows according to a WindowFn. The output of Window contains the same elements as input, but they have been logically assigned to windows. The next GroupByKeys, including one within composite transforms, will group by the combination of keys and windows.

Windowing a PCollection allows chunks of it to be processed individually, before the entire PCollection is available. This is especially important for PCollections with unbounded size, since the full PCollection is never available at once.

For PCollections with a bounded size, by default, all data is implicitly in a single window, and this replicates conventional batch mode. However, windowing can still be a convenient way to express time-sliced algorithms over bounded PCollections.

As elements are assigned to a window, they are are placed into a pane. When the trigger fires all of the elements in the current pane are output.

The DefaultTrigger will output a window when the system watermark passes the end of the window. See AfterWatermark for details on the watermark.