com.google.cloud.dataflow.sdk.util

Interface ActiveWindowSet<W extends BoundedWindow>

Type Parameters:

W - the types of windows being managed

All Known Implementing Classes:

MergingActiveWindowSet, NonMergingActiveWindowSet

public interface ActiveWindowSet<W extends BoundedWindow>

Tracks the windows that are active.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	ActiveWindowSet.MergeCallback<W extends BoundedWindow> Callback for mergeIfAppropriate(W, com.google.cloud.dataflow.sdk.util.ActiveWindowSet.MergeCallback<W>).

Method Summary

Modifier and Type	Method and Description
boolean	add(W window) Add a window to the ActiveWindowSet.
boolean	mergeIfAppropriate(W window, ActiveWindowSet.MergeCallback<W> mergeCallback) Invoke merge on the associated WindowFn, and return true if the window still exists afterwards.
void	persist() Save any state changes needed.
void	remove(W window) Remove a window from the ActiveWindowSet.
Iterable<W>	sourceWindows(W window) Return the set of windows that were merged to produce window.

Method Detail

persist

void persist()

Save any state changes needed.

add

boolean add(W window)

Add a window to the ActiveWindowSet.

Returns:

false if the window was definitely not-active before being added, true if it either was already active, or the implementation doesn't have enough information to know.

remove

void remove(W window)

Remove a window from the ActiveWindowSet.

mergeIfAppropriate

boolean mergeIfAppropriate(W window,
                           ActiveWindowSet.MergeCallback<W> mergeCallback)
                    throws Exception

Invoke merge on the associated WindowFn, and return true if the window still exists afterwards.

Throws:

Exception

sourceWindows

Iterable<W> sourceWindows(W window)

Return the set of windows that were merged to produce window. If the associated WindowFn never merges windows, then this should return the singleton list containing window.