Architecture Overview¶

This page provides a high-level map of the etcion codebase and its class hierarchy. For full API details see the API Reference.

Module Map¶

Module	Responsibility
`metamodel/concepts.py`	Root ABCs: Concept, Element, Relationship
`metamodel/elements.py`	Abstract element hierarchy (ActiveStructure, Behavior, etc.)
`metamodel/business.py`	Business layer concrete elements
`metamodel/application.py`	Application layer concrete elements
`metamodel/technology.py`	Technology layer concrete elements
`metamodel/physical.py`	Physical layer concrete elements
`metamodel/strategy.py`	Strategy layer concrete elements
`metamodel/motivation.py`	Motivation layer concrete elements
`metamodel/implementation_migration.py`	Implementation & Migration layer elements
`metamodel/relationships.py`	All 11 relationship types + Junction
`metamodel/model.py`	Model container, QueryBuilder
`metamodel/viewpoints.py`	Viewpoint, View, Concern
`metamodel/viewpoint_catalogue.py`	Predefined viewpoint definitions
`metamodel/profiles.py`	Profile, Specialization, extended attributes
`metamodel/notation.py`	NotationMetadata
`metamodel/mixins.py`	Shared mixins
`validation/permissions.py`	Appendix B permission table, `is_permitted()`
`validation/rules.py`	ValidationRule base
`derivation/engine.py`	DerivationEngine
`serialization/xml.py`	XML serialization (Exchange Format)
`serialization/json.py`	JSON serialization
`serialization/registry.py`	Type registry for deserialization
`comparison.py`	`diff_models()`, ModelDiff, ConceptChange
`conformance.py`	ConformanceProfile
`enums.py`	Layer, Aspect, AccessMode, etc.
`exceptions.py`	PyArchiError hierarchy

Class Hierarchy¶

The diagram below shows the core type hierarchy to two levels of depth. Concrete layer-specific elements (e.g. BusinessActor, ApplicationComponent) inherit from the abstract nodes shown here -- see the Elements API reference for the full taxonomy.

classDiagram
    Concept <|-- Element
    Concept <|-- Relationship
    Concept <|-- RelationshipConnector

    Element <|-- ActiveStructureElement
    Element <|-- BehaviorElement
    Element <|-- PassiveStructureElement
    Element <|-- CompositeElement
    Element <|-- MotivationElement
    Element <|-- StructureElement

    ActiveStructureElement <|-- ExternalActiveStructureElement
    ActiveStructureElement <|-- InternalActiveStructureElement

    BehaviorElement <|-- ExternalBehaviorElement
    BehaviorElement <|-- InternalBehaviorElement
    BehaviorElement <|-- Event

    Relationship <|-- StructuralRelationship
    Relationship <|-- DependencyRelationship
    Relationship <|-- DynamicRelationship
    Relationship <|-- OtherRelationship

    RelationshipConnector <|-- Junction

Reading the diagram

Element subtypes map to the ArchiMate aspect classification (active structure, behavior, passive structure).
Relationship subtypes follow the specification's four relationship categories.
RelationshipConnector contains only Junction, used to combine relationships.