Object - streams : TimeLengthWindow

This is a sliding time window that, at a given time holds the last windowLength events that arrived during last windowTime period, and gets updated for every event arrival and expiry. E.g. from inputStream window timeLength(4000, 10) select inputStream.name, inputStream.age, sum(inputStream.age) as sumAge, count() as count group by inputStream.name => (TeacherOutput [] teachers) { foreach var t in teachers { outputStream.publish(t); } } The timeLength window should only have two parameters ( windowTime, windowLength)

Constructor

__init

( function(StreamEvent[]) returns (()) nextProcessPointer, any windowParameters)

  • nextProcessPointer function(StreamEvent[]) returns (())
  • windowParameters any

Methods

Fields

  • timeInMilliSeconds int
  • description

  • length int
  • description

  • windowParameters any
  • description

  • count int 0
  • description

  • nextProcessPointer function(StreamEvent[]) returns (())
  • description

initParameters

Parameters

  • parameters any

process

The process function process the incoming events to the events and update the current state of the window.

Parameters

  • streamEvents StreamEvent[]
  • The array of stream events to be processed.

getCandidateEvents

(StreamEvent originEvent, function(map, map) returns (boolean) conditionFunc, boolean isLHSTrigger)

returns [StreamEvent?, StreamEvent?]

Returns the events(State) which match with the where condition in the join clause for a given event.

Parameters

  • originEvent StreamEvent
  • The event against which the state or the events being held by the window is matched.

  • conditionFunc function(map, map) returns (boolean)
  • The function pointer to the lambda function which contain the condition logic in where clause.

  • isLHSTrigger boolean (default true)
  • Specify if the join is triggered when the lhs stream received the events, if so it should be true. Most of the time it is true. In rare cases, where the join is triggered when the rhs stream receives events this should be false.

  • Return Type

    ([StreamEvent?, StreamEvent?])
  • Returns an array of 2 element tuples of events. A tuple contains the matching events one from lhs stream and one from rhs stream.

saveState

()

returns map

Return current state to be saved as a map of any typed values.

  • Return Type

    (map)
  • A map of any typed values.

restoreState

Restores the saved state which is passed as a map of any typed values.

Parameters

  • state map
  • A map of typed any values. This map contains the values to be restored from the persisted data.