WindowFn (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

Class WindowFn<T,W extends BoundedWindow>

  • java.lang.Object
  • Type Parameters:
    T - type of elements being windowed
    W - BoundedWindow subclass used to represent the windows used by this WindowFn
    All Implemented Interfaces:
    HasDisplayData, Serializable
    Direct Known Subclasses:
    InvalidWindows, NonMergingWindowFn, Sessions

    public abstract class WindowFn<T,W extends BoundedWindow>
    extends Object
    implements Serializable, HasDisplayData
    The argument to the Window transform used to assign elements into windows and to determine how windows are merged. See Window for more information on how WindowFns are used and for a library of predefined WindowFns.

    Users will generally want to use the predefined WindowFns, but it is also possible to create new subclasses.

    To create a custom WindowFn, inherit from this class and override all required methods. If no merging is required, inherit from NonMergingWindowFn instead. If no merging is required and each element is assigned to a single window, inherit from PartitioningWindowFn. Inheriting from the most specific subclass will enable more optimizations in the runner.

    See Also:
    Serialized Form
    • Constructor Detail

      • WindowFn

        public WindowFn()