Package org.apache.beam.sdk.transforms.windowing

Class BoundedWindow

  • Direct Known Subclasses:
    EncodedBoundedWindow, GlobalWindow, IntervalWindow
    public abstract class BoundedWindow
extends java.lang.Object
    A BoundedWindow represents window information assigned to data elements.

    It has one method maxTimestamp() to define an upper bound (inclusive) for element timestamps. A WindowFn must assign an element only to windows where maxTimestamp() is greater than or equal to the element timestamp. When the watermark passes the maximum timestamp, all data for a window is estimated to be received.

    A window does not need to have a lower bound. Only the upper bound is mandatory because it governs management of triggering and discarding of the window.

    Windows must also implement Object.equals(java.lang.Object) and Object.hashCode() such that windows that are logically equal will be treated as equal by equals() and hashCode().

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static org.joda.time.Instant TIMESTAMP_MAX_VALUE
      The maximum value for any Beam timestamp.
      static org.joda.time.Instant TIMESTAMP_MIN_VALUE
      The minimum value for any Beam timestamp.

    • Constructor Summary

      Constructors 
      Constructor Description
      BoundedWindow()  

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      static java.lang.String formatTimestamp​(org.joda.time.Instant timestamp)
      Formats a Instant timestamp with additional Beam-specific metadata, such as indicating whether the timestamp is the end of the global window or one of the distinguished values TIMESTAMP_MIN_VALUE or TIMESTAMP_MIN_VALUE.
      abstract org.joda.time.Instant maxTimestamp()
      Returns the inclusive upper bound of timestamps for values in this window.
      static void validateTimestampBounds​(org.joda.time.Instant timestamp)
      Validates that a given timestamp is within min and max bounds.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • TIMESTAMP_MIN_VALUE

        public static final org.joda.time.Instant TIMESTAMP_MIN_VALUE
        The minimum value for any Beam timestamp. Often referred to as "-infinity".

        This value and TIMESTAMP_MAX_VALUE are chosen so that their microseconds-since-epoch can be safely represented with a long.

      • TIMESTAMP_MAX_VALUE

        public static final org.joda.time.Instant TIMESTAMP_MAX_VALUE
        The maximum value for any Beam timestamp. Often referred to as "+infinity".

        This value and TIMESTAMP_MIN_VALUE are chosen so that their microseconds-since-epoch can be safely represented with a long.

    • Constructor Detail

      • BoundedWindow

        public BoundedWindow()

    • Method Detail

      • formatTimestamp

        public static java.lang.String formatTimestamp​(org.joda.time.Instant timestamp)
        Formats a Instant timestamp with additional Beam-specific metadata, such as indicating whether the timestamp is the end of the global window or one of the distinguished values TIMESTAMP_MIN_VALUE or TIMESTAMP_MIN_VALUE.

      • maxTimestamp

        public abstract org.joda.time.Instant maxTimestamp()
        Returns the inclusive upper bound of timestamps for values in this window.

      • validateTimestampBounds

        public static void validateTimestampBounds​(org.joda.time.Instant timestamp)
        Validates that a given timestamp is within min and max bounds.
        Parameters:
        timestamp - timestamp to validate