Rules

The Rules OSID provides a means to evaluate rules and retrieve results. A Rule represents a something that can be executed and can be organized into Engines. The rule evaluation accepts a Condition that is used to supply input conditions to the rule engine.

The Rules OSID does not define a means for authoring rules. Definitions exist for evaluating, examining and organizing rules. A Rule is identified by an Id such that a consumer wishing to evaluate a rule must have knowledge of the Rule Id along with the expectations of data (recod Type) required in the Condition. The Rule also implies the structure of the Result, which can be a simple boolean value or another structure defined in a Result Record.

Engines can be organized into hierarchies for federation. An engine that is a parent of another engine makes visible the rules of its children.

Example where the consumer executes a rule with knowledge of the Rule Id, ConditionRecord Type, and the meaning of the Result. 

RuleEvaluationSession session = manager.getRuleEvaluationSession();
Condition condition = session.getConditionForRule(shouldIWearACoatRuleId);
if (!condition.hasRecordType(temperatureConditionRecordType) {
    error ("temperature condition record not supported");
}

TemperatureCondition temp = condition.getConditionRecord(temperatureConditionRecordType);
temp.setTemperature(28);

if (session.evaluateRule(shouldIWearACoatRuleId, condition) {
    putOnACoat();
}
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