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Jjodel Object Model (JjOM)

The Jjodel Object Model (JjOM) is the structured runtime framework at the heart of Jjodel. It represents all modeling components — models, metamodels, and viewpoints — in a unified, accessible structure.

Core Modeling Constructs

Section titled “Core Modeling Constructs”

JjOM is built on a small set of foundational constructs:

DPackage

Section titled “DPackage”

A logical container for grouping related classes. Packages can be nested to create hierarchical namespaces.

Key properties:

  • name: String — the package name
  • packages: Array<DPackage> — nested sub-packages
  • objects: Array<DObject> — contained elements

DClass

Section titled “DClass”

The fundamental building block of metamodels. A DClass defines an element type with its properties and relationships.

Key properties:

  • name: String — the class name (unique within its package)
  • isAbstract: Boolean — if true, the class cannot be directly instantiated
  • isInterface: Boolean — marks the class as an interface
  • isRootable: Boolean — if true, instances can be root elements in a model
  • isSingleton: Boolean — restricts to a single instance per model
  • isFinal: Boolean — prevents subclassing
  • isPrimitive: Boolean — marks the class as a primitive type
  • isMetamodel: Boolean — indicates this class belongs to the metamodel level
  • extends: Array<DClass> — parent classes (inheritance)
  • extendedBy: Array<DClass> — known subclasses
  • attributes: Array<DAttribute> — owned attributes
  • references: Array<DReference> — owned references
  • operations: Array<DOperation> — owned operations
  • features: Array<Feature> — combined list of all structural features
  • instances: Array<DObject> — all instances of this class
  • allInstances: Array<DObject> — all instances including subclass instances

DAttribute

Section titled “DAttribute”

A typed property belonging to a class.

Key properties:

  • name: String — the attribute name
  • type — the data type (String, Integer, Boolean, Float, or enum)

DReference

Section titled “DReference”

A relationship between two classes.

Key properties:

  • name: String — the reference name
  • target: DClass — the target class
  • containment: Boolean — whether this is a containment (composition) reference
  • multiplicity — lower and upper bounds

DOperation

Section titled “DOperation”

A behavioral feature belonging to a class.

DObject

Section titled “DObject”

A runtime instance of a DClass. DObjects hold actual attribute values and reference targets.

Key properties:

  • id: Pointer — unique identifier (note: IDs generated by DObject.new() are temporary)
  • className: String — the name of the instantiated class
  • instanceOf: DClass — the metamodel class this object conforms to
  • parent: * — the containing element (if any)
Section titled “Navigating the JjOM”

The JjOM is fully navigable at runtime through JjEL expressions and the Console. You can traverse the entire model graph starting from any element:

// From a class, get all its instances
Person.allInstances


// From an instance, navigate to its class
myPerson.instanceOf.name  // → "Person"


// From a class, get its features
Person.features  // → [name, age, address, ...]


// Traverse containment
myPackage.objects  // → all contained elements

JjOM and the LModel Proxy

Section titled “JjOM and the LModel Proxy”

In Jjodel’s internal architecture, the LModel proxy provides a convenient API for accessing and manipulating the JjOM. LModel finds elements by name and writes attribute values using the $attr.value pattern. This is primarily relevant for internal development and advanced customization.