Identity

Identity is the sameness by which a subject is distinguished from others and tracked as the same subject over time even when its values or State change. An Identifier is a value that represents or refers to Identity; it is not the Identity itself.

SimpleModeling manages the boundary and Lifecycle of an Entity Object through Identity. A Value Object is compared by value equality rather than persistent Identity. The meaning and identifier scope of Identity are specified for each kind of subject, including Objects, Glossary Terms, and Capabilities.

simplemodeling-lib does not collapse Identity into one Scala type. Identifier is an identifying value, ObjectId wraps an Identifier, UniversalId is an operational identifier, and CanonicalId is an opaque Identifier for correlation. Identified and Identifiable are contracts for obtaining a required or optional UniversalId from a subject. The upper-layer Model determines which Identity an Identifier represents.