org.apache.beam.sdk.transforms.windowing

Class WindowFn.MergeContext

java.lang.Object

org.apache.beam.sdk.transforms.windowing.WindowFn.MergeContext

Enclosing class:

WindowFn<T,W extends BoundedWindow>

public abstract class WindowFn.MergeContext
extends Object

Information available when running WindowFn.mergeWindows(org.apache.beam.sdk.transforms.windowing.WindowFn<T, W>.MergeContext).

Constructor Summary

Constructors

Constructor and Description
MergeContext()

Method Summary

Modifier and Type	Method and Description
abstract void	merge(Collection<W> toBeMerged, W mergeResult) Signals to the framework that the windows in toBeMerged should be merged together to form mergeResult.
abstract Collection<W>	windows() Returns the current set of windows.

Methods inherited from class java.lang.Object

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

Constructor Detail

MergeContext

public MergeContext()

Method Detail

windows

public abstract Collection<W> windows()

Returns the current set of windows.

merge

public abstract void merge(Collection<W> toBeMerged,
                           W mergeResult)
                    throws Exception

Signals to the framework that the windows in toBeMerged should be merged together to form mergeResult.

toBeMerged should be a subset of windows() and disjoint from the toBeMerged set of previous calls to merge.

mergeResult must either not be in windows() or be in toBeMerged.

Throws:

IllegalArgumentException - if any elements of toBeMerged are not in windows(), or have already been merged

Exception