Object -
streams
:
SortWindow
The sort window hold a given number of events and emit the expired events in the ordered by the given fields.
E.g.
from inputStream window sort(10, inputStream.age, "ascending", inputStream.name, "descending")
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 sort
window should have three or more odd no of parameters (
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
- lengthToKeep int
-
description
- windowParameters any[]
-
description
- sortedWindow LinkedList
-
description
- fields string[]
-
description
- sortTypes string[]
-
description
- nextProcessPointer
function(StreamEvent?[]) returns (())
-
description
- fieldFuncs
function(map) returns (anydata)
[] -
description
- mergeSort MergeSort
-
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.