WindowFn.MergeContext (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

Warning: Dataflow SDK 1.x for Java is unsupported as of October 16, 2018. After August 12, 2020, you can use unsupported SDKs temporarily while you upgrade your pipelines. For more information, see Using an unsupported SDK.

For information on migrating from the 1.x SDK, see Migrating from Dataflow SDK 1.x for Java.

Note: If you are using Cloud Dataflow SDK version 2.x, see the Apache Beam API reference documentation.

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

Class WindowFn.MergeContext

• java.lang.Object
• • com.google.cloud.dataflow.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(com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn<T, W>.MergeContext).

• • Constructor Summary

    Constructors 

    Constructor and Description
    MergeContext()

  • Method Summary

    All Methods Instance Methods Abstract Methods 

    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