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Comment: Session window functionality


  • start: The start condition for a predicate window. If the condition evaluates to true, the windows is opened until the end predicate evaluates to true (or if not given the start predicate evaluates to false). Note, that all elements that are not inside a window are send to ouput port 1
  • end: The end condition for a predicate window. The tuple for which this condition is evaluated to true is only part of the result, if keepEndingElement is set to true!
  • sameStartTime: For predicate windows: If set to true, all produced elements get the same start timestamp
  • size: The maximum size of the window. Can be either a single number or a pair of a number and a time unit. Possible values for the unit are one of TimeUnit like SECONDS, NANOSECODS etc. - default time is the base time of the stream (typically milliseconds)
  • keepEndingElement: Typically, the object that fulfils the end condition will not be part of the result. If setting this attribute to true, the element will be part

  • partition: Evaluate the predicates on partitioned defined by different values of this attribute (similar to group by in aggreation)

  • closeWindowWithHeartbeat: if true, the window is closed when a heartbeat is received. Take a look at the session window to see how it works.

Remark: This is a blocking operator. The operator does not write elements before it sees new elements not belonging to the window anymore (similiar to ElementWindow)