dynamicselect
The
dynamicselect keyword specifies the
dynamic selection of a rule.
Purpose
This keyword is used to specify the dynamic selection of a rule in a rule task body.
Context
Rule task definitions
Syntax
body = dynamicselect(?rule) {...}
Description
The body of a rule task contains a list of rules. You can either specify each rule name
explicitly (extension) or have the list of rules computed from the code, which uses the
dynamicselect keywords (comprehension). The code must return a value of type
boolean. It is evaluated each time the rule task is invoked.
To optimize performance, the decision engine does not execute the code statements the same number
of times depending on whether they are before the use of the
(?rule) variable or
after. Statements that come before the statement in which the (?rule) variable is
used are calculated only once per ruletask execution, when the task body is evaluated. Statements
including and after the first statement in which the (?rule) variable is used are
calculated for every rule under review in the task scope. For example, ?contract is
a ruleset variable with a country attribute and an effectiveDate attribute, and the
task applies only for a selection of countries and only to the rules whose
effectiveDate covers the one of the contract:
body = dynamicselect(?rule) {
return ?contract.country in { "France", "Spain", "Italy"} &&
?contract.effectiveDate.after((java.time.*)?rule.getPropertyValue("effectiveDate"));
}?contract.country in { "France", "Spain", "Italy"} is
evaluated once per task execution and
?contract.effectiveDate.after((java.time.*)?rule.getPropertyValue("effectiveDate"))
is calculated once per rule for each task execution. However, if you write the following code, then both conditions are calculated once per rule for
each task execution:
body = dynamicselect(?rule) {
return ?contract.effectiveDate.after((java.time.*)?rule.getPropertyValue("effectiveDate")) &&
?contract.country in { "France", "Spain", "Italy" };
}