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. See Migrating from Dataflow SDK 1.x for Java for migration guidance.

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