Detailed Behavior

Each instance of combineSuccessionSets must:

take a single argument which must be a list of rule objects, each of which must ultimately inherit from the PropagatorRuleSet.ActiveSuccessionSet rule class;
nominate a rule class to use as the type of the new rule object created and returned when the expression is evaluated.

When an instance of combineSuccessionSets is evaluated, a rule object of the nominated return rule class is created. The attribute values on this return rule object will be set by matching their names to those on the input succession set rule objects being combined.

For periods of time not covered by the input succession set rule objects (i.e. for the "gaps" between periods, or the values used if the input list is empty), then default values will be used as shown in the following table:

Table 1. Mapping from Cúram Domain Types to CER Rule Attribute Types
Data type for succession set attribute used as an input timeline	Default value, used for "gaps" between input succession sets
Timeline<Number>	0
Timeline<Boolean>	false
Timeline<Code table entry>	null (not-specified) entry from the code table
(any other data type)	null

If the input list of succession set of rule objects is empty (e.g. a person who has never been absent from their household), then the default values shown above will be used throughout the entire timelines.

The combineSuccessionSets expression applies validations when the rule set is validated, and also when the expression is evaluated, as described in the following sections.

Validation checks made when the rule set is validated

Each instance of combineSuccessionSets will be checked to ensure that it meets the following constraints:

the single argument to the expression must return a list of rule objects, and the rule class for these rule objects must be annotated with the SuccessionSetPopulation annotation;;
for the rule class nominated as the return type of the combineSuccessionSets expression:
- the rule class must not be abstract and must not contain any initialized attributes; and
- each rule attribute on the rule class that has a specified derivation must have an identically-named attribute on the rule class for the input list of rule objects.

If the above conditions are not met, then the rule set will not pass validation checks.

Validation checks made when `combineSuccessionSets` is evaluated

When an instance of combineSuccessionSets is evaluated at run time, each rule object for a contributing succession set being combined must:

have a non-blank start date - i.e. the value of the attribute named in the SuccessionSetPopulation annotation must not be null; and
not overlap with any other contributing succession set rule objects - i.e. the lifetimes of each contributing succession set (calculated with reference to the start/end date attributes named in the SuccessionSetPopulation annotation) must each cover distinct periods. In particular, at most one contributing succession set is allowed to be open-ended.

If the above conditions are not met, then combineSuccessionSets throws an appropriate exception.

Detailed Behavior

Validation checks made when the rule set is validated

Validation checks made when combineSuccessionSets is evaluated

Validation checks made when `combineSuccessionSets` is evaluated