stringUnion Function Description

Description

This function takes two or more arguments that are both a bag of string values. It returns a bag of string such that it contains all elements of all the argument bags. The function gets rid of duplicates, as determined by the equality functions.

stringUnion belongs to the ALFA function reference's Set functions category. It maps to the XACML function identifier urn:oasis:names:tc:xacml:1.0:function:string-union, takes 2 or more arguments and returns a value of type A bag of values of type string with no duplicates..

Property Value
Category Set functions
# Arguments 2 or more
Arguments
  • A bag of type string
  • A bag of type string
  • Optionally more bags of type string
Return Value A bag of values of type string with no duplicates.
Expressed As pre-fix
Representation ALFA short name
Allowed In Target false
ALFA Shorthand None
Commutative true

Example

/**
* Allow access if the country is either an EU country or an EEA country (Norway, Switzerland, Iceland, Liechtenstein) 
*/
rule stringUnionExample{
    permit
    condition stringIsIn(stringOneAndOnly(country), stringUnion(euCountries,eeaCountries))
}

In this example, we use the stringUnion function in conjunction with stringIsIn to determine whether a single atomic value is in the union of 2 bags of values. This also shows how functions can be combined together in ALFA.

See Also

Related Functions

Other functions in the Set functions category:

Browse the full ALFA function reference.