Object -
streams
:
ExternalTimeBatchWindow
This is a batch (tumbling) time window based on external time, that holds events arrived during window time periods,
and gets updated for every window time.
E.g.
from inputStream window externalTimeBatch(inputStream.timestamp, 1000, 500, 1200, true)
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 externalTimeBatch
window should only have two to five parameters (timestamp field,
Constructor
__init
( function(StreamEvent[]) returns (())
nextProcessPointer, any windowParameters)
- nextProcessPointer
function(StreamEvent[]) returns (())
- windowParameters any
Methods
The process
function process the incoming events to the events and update the current state of the window.
Returns the events(State) which match with the where condition in the join clause for a given event.
Return current state to be saved as a map of any
typed values.
Restores the saved state which is passed as a map of any
typed values.
Fields
- timeToKeep int
-
description
- currentEventChunk LinkedList
-
description
- expiredEventChunk LinkedList
-
description
- resetEvent StreamEvent? ()
-
description
- startTime int -1
-
description
- isStartTimeEnabled boolean false
-
description
- replaceTimestampWithBatchEndTime boolean false
-
description
- flushed boolean false
-
description
- endTime int -1
-
description
- schedulerTimeout int 0
-
description
- lastScheduledTime int
-
description
- lastCurrentEventTime int 0
-
description
- nextProcessPointer
function(StreamEvent[]) returns (())
-
description
- timeStamp string
-
description
- storeExpiredEvents boolean false
-
description
- outputExpectsExpiredEvents boolean false
-
description
- windowParameters any
-
description
- scheduler Scheduler? ()
-
description
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 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.
Return current state to be saved as a map of any
typed values.
-
Return Type
(map) A map of
any
typed values.
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.
Parameters
- currStreamEvent StreamEvent
Parameters
- currentTime int
- startTime_ int
- timeToKeep_ int
-
Return Type
(int)
Parameters
- firstStreamEvent StreamEvent