EStructuralFeatures

In the Eclipse Modeling Framework (EMF), EStructuralFeatures refer to the structural components that define the properties of an EClass. They encompass EAttributes and EReferences, which describe, respectively, primitive data values and references to other objects. The common interface EStructuralFeature provides metadata shared by both kinds, including the feature’s name, its type (via the containing ETypedElement), and multiplicity via lowerBound and upperBound. It also exposes behavioral flags such as changeable, volatile, transient, derived, unsettable, ordered, and unique, as well as a default value literal.

EAttribute and EReference implement EStructuralFeature. EReference adds behavior specific to references, such as containment and the opposite feature, enabling bidirectional links between objects. EAttributes store values for data types (for example, strings or integers), while EReferences model relationships to other EObjects and can be single-valued or multi-valued depending on the bounds.

Structural features play a central role in EMF tooling and code generation. They enable runtime reflection on EClasses, support serialization and deserialization of models, and underpin editor generation and model validation. By inspecting the set of EStructuralFeatures of an EClass, tools can dynamically present properties, enforce multiplicity constraints, and navigate model structures without requiring hard-coded knowledge of specific classes.

Example: an EClass Person might define EStructuralFeatures such as an EAttribute named name of type EString and an EAttribute named age of type EInt, along with an EReference named friends with upperBound set to -1 (unbounded) to represent a list of Person references.

See also: EClass, EAttribute, EReference, Ecore, ETypedElement.