SlidingWindows (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

Warning: Cloud Dataflow SDK 1.x for Java is unsupported as of October 16, 2018. See Migrating from Cloud 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 SlidingWindows

• java.lang.Object
• • com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn<T,W>
  • • com.google.cloud.dataflow.sdk.transforms.windowing.NonMergingWindowFn<Object,IntervalWindow>
    • • com.google.cloud.dataflow.sdk.transforms.windowing.SlidingWindows

• All Implemented Interfaces:

  HasDisplayData, Serializable

  ---

  
  

  public class SlidingWindows
  extends NonMergingWindowFn<Object,IntervalWindow>

  A WindowFn that windows values into possibly overlapping fixed-size timestamp-based windows.

  For example, in order to window data into 10 minute windows that update every minute:

   
   PCollection<Integer> items = ...;
   PCollection<Integer> windowedItems = items.apply(
     Window.<Integer>into(SlidingWindows.of(Duration.standardMinutes(10))));
    

  See Also:

  Serialized Form

• • Nested Class Summary

    • Nested classes/interfaces inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn

      WindowFn.AssignContext, WindowFn.MergeContext

  • Method Summary

    All Methods Static Methods Instance Methods Concrete Methods 

    Modifier and Type	Method and Description
    Collection<IntervalWindow>	assignWindows(WindowFn.AssignContext c) Given a timestamp and element, returns the set of windows into which it should be placed.
    boolean	equals(Object object)
    SlidingWindows	every(Duration period) Returns a new SlidingWindows with the original size, that assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.
    Duration	getOffset()
    OutputTimeFn<? super IntervalWindow>	getOutputTimeFn() Ensures that later sliding windows have an output time that is past the end of earlier windows.
    Duration	getPeriod()
    IntervalWindow	getSideInputWindow(BoundedWindow window) Return the earliest window that contains the end of the main-input window.
    Duration	getSize()
    int	hashCode()
    boolean	isCompatible(WindowFn<?,?> other) Returns whether this performs the same merging as the given WindowFn.
    static SlidingWindows	of(Duration size) Assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.
    void	populateDisplayData(DisplayData.Builder builder) Register display data for the given transform or component.
    Coder<IntervalWindow>	windowCoder() Returns the Coder used for serializing the windows used by this windowFn.
    SlidingWindows	withOffset(Duration offset) Assigns timestamps into half-open intervals of the form [N * period + offset, N * period + offset + size).

    • Methods inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.NonMergingWindowFn

      isNonMerging, mergeWindows

    • Methods inherited from class com.google.cloud.dataflow.sdk.transforms.windowing.WindowFn

      assignsToSingleWindow, getOutputTime

    • Methods inherited from class java.lang.Object

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

• • Method Detail

    • of

      public static SlidingWindows of(Duration size)

      Assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.

      If every(org.joda.time.Duration) is not called, the period defaults to the largest time unit smaller than the given duration. For example, specifying a size of 5 seconds will result in a default period of 1 second.

    • every

      public SlidingWindows every(Duration period)

      Returns a new SlidingWindows with the original size, that assigns timestamps into half-open intervals of the form [N * period, N * period + size), where 0 is the epoch.

    • withOffset

      public SlidingWindows withOffset(Duration offset)

      Assigns timestamps into half-open intervals of the form [N * period + offset, N * period + offset + size).

      Throws:

      IllegalArgumentException - if offset is not in [0, period)

    • windowCoder

      public Coder<IntervalWindow> windowCoder()

      Description copied from class: WindowFn
      Returns the Coder used for serializing the windows used by this windowFn.

      Specified by:

      windowCoder in class WindowFn<Object,IntervalWindow>

    • assignWindows

      public Collection<IntervalWindow> assignWindows(WindowFn.AssignContext c)

      Description copied from class: WindowFn
      Given a timestamp and element, returns the set of windows into which it should be placed.

      Specified by:

      assignWindows in class WindowFn<Object,IntervalWindow>

    • getSideInputWindow

      public IntervalWindow getSideInputWindow(BoundedWindow window)

      Return the earliest window that contains the end of the main-input window.

      Specified by:

      getSideInputWindow in class WindowFn<Object,IntervalWindow>

    • isCompatible

      public boolean isCompatible(WindowFn<?,?> other)

      Description copied from class: WindowFn
      Returns whether this performs the same merging as the given WindowFn.

      Specified by:

      isCompatible in class WindowFn<Object,IntervalWindow>

    • populateDisplayData

      public void populateDisplayData(DisplayData.Builder builder)

      Description copied from class: WindowFn
      Register display data for the given transform or component.

      populateDisplayData(DisplayData.Builder) is invoked by Pipeline runners to collect display data via DisplayData.from(HasDisplayData). Implementations may call super.populateDisplayData(builder) in order to register display data in the current namespace, but should otherwise use subcomponent.populateDisplayData(builder) to use the namespace of the subcomponent.

      By default, does not register any display data. Implementors may override this method to provide their own display data.

      Specified by:

      populateDisplayData in interface HasDisplayData

      Overrides:

      populateDisplayData in class WindowFn<Object,IntervalWindow>

      Parameters:

      builder - The builder to populate with display data.

      See Also:

      HasDisplayData

    • getPeriod

      public Duration getPeriod()

    • getSize

      public Duration getSize()

    • getOffset

      public Duration getOffset()

    • getOutputTimeFn

      @Experimental(value=OUTPUT_TIME)
      public OutputTimeFn<? super IntervalWindow> getOutputTimeFn()

      Ensures that later sliding windows have an output time that is past the end of earlier windows.

      If this is the earliest sliding window containing inputTimestamp, that's fine. Otherwise, we pick the earliest time that doesn't overlap with earlier windows.

      Overrides:

      getOutputTimeFn in class WindowFn<Object,IntervalWindow>

    • equals

      public boolean equals(Object object)

      Overrides:

      equals in class Object

    • hashCode

      public int hashCode()

      Overrides:

      hashCode in class Object