sizeOfSet (Function)

Returns the size of an object of type java.util.Set.

Syntax

<INT> sizeOfSet(<OBJECT> set)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
set	The set object. This parameter should be of type java.util.Set. A set object may be created by the set attribute aggregator.		OBJECT	No	Yes

Example

This example demonstrates the use of the sizeOfSet() function to calculate the size of a set containing unique stock symbols. The example consists of a series of queries that process records from an input stream of stock data, create a set of unique stock symbols, and then calculate the size of that set.

Query 1

@info(name = 'query1')
INSERT INTO initStream
SELECT initSet(symbol) AS initialSet
FROM stockStream;

This query, named 'query1', processes records from the stockStream and creates an initial set of symbol values using the initSet(symbol) function. For each record in the stockStream, the function adds the symbol to the set. The resulting set, named initialSet, is then inserted into the initStream.

Essentially, this query processes records in the stockStream and creates a new record in the initStream containing a set of unique symbol values.

Query 2

@info(name = 'query2')
INSERT INTO distinctStockStream
SELECT union(initialSet) AS distinctSymbols
FROM initStream WINDOW TUMBLING_TIME(10 sec);

This query, named 'query2', processes records from the initStream and applies a tumbling time window of 10 seconds. For each window, the union(initialSet) function is applied to create a single set containing the union of all initialSet values within that window. The resulting set, named distinctSymbols, contains unique stock symbols from the window and is inserted into the distinctStockStream.

Essentially, this query processes records in the initStream using a tumbling time window and creates new records in the distinctStockStream containing the union of unique stock symbols from each window.

Query 3

@info(name = 'query3')
INSERT INTO sizeStream
SELECT sizeOfSet(distinctSymbols) AS sizeOfSymbolSet
FROM distinctStockStream;

This query, named 'query3', processes records from the distinctStockStream and calculates the size of the distinctSymbols set using the sizeOfSet(distinctSymbols) function. The resulting value, named sizeOfSymbolSet, represents the number of unique stock symbols in the set and is inserted into the sizeStream.

Essentially, this query processes records in the distinctStockStream and creates new records in the sizeStream containing the size of the unique stock symbols set.