Package com.hazelcast.jet.pipeline

Class SlidingWindowDefinition

  • All Implemented Interfaces:
    java.io.Serializable
    public class SlidingWindowDefinition
extends WindowDefinition
    Represents the definition of a sliding window.
    Since:
    Jet 3.0
    See Also:
    Serialized Form

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      SlidingWindowDefinition setEarlyResultsPeriod​(long earlyResultPeriodMs)
      Sets the period in milliseconds at which the windowed aggregation stage will emit partial results of all the windows that contain some data, but the watermark hasn't yet advanced enough to close them and emit the final results.
      long slideBy()
      Returns the size of the sliding step.
      long windowSize()
      Returns the length of the window (the size of the timestamp range it covers).

      • Methods inherited from class java.lang.Object

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

    • Method Detail

      • setEarlyResultsPeriod

        public SlidingWindowDefinition setEarlyResultsPeriod​(long earlyResultPeriodMs)
        Description copied from class: WindowDefinition
        Sets the period in milliseconds at which the windowed aggregation stage will emit partial results of all the windows that contain some data, but the watermark hasn't yet advanced enough to close them and emit the final results.

        Consider this example: we're collecting a 1-minute tumbling window of stock exchange data. The results we're getting pertain to the minute that just elapsed, but we'd also like to detect any sudden changes within the running minute. We can set the early results period to 1000 ms and get an update every second for the window that's currently being filled with data.

        Note that, for a sliding window, there will be many incomplete windows that contain some data and you'll get the early results for all of them. Similarly, if you configure a high-enough maxLag for the event timestamps, there can be more than one tumbling/session window with early results.

        The default value is zero, which means "don't emit early results".

        Overrides:
        setEarlyResultsPeriod in class WindowDefinition
        Parameters:
        earlyResultPeriodMs - the period in milliseconds from one start of the emission of early results to the next one
        Returns:
        this

      • windowSize

        public long windowSize()
        Returns the length of the window (the size of the timestamp range it covers). It is an integer multiple of slideBy().

      • slideBy

        public long slideBy()
        Returns the size of the sliding step.