ObjectSpecsModeler: Main Concept 2

Feature instantiation and persistency


* A feature is initiated from its StartUp that is retrieved from the catalog
* The instance will be an exact copy of the startup and will retain any
  attributes with their initial default values
* Because a feature ia a late type, the StartUp is retrieved from the catalog
  at Run-Time and it is instantiated in order to create a new feature
* To be persistent a feature must be instantiated in a container: This container
  belongs to a document.
  - Saving the document will in turn save the feature



Feature instantiation and derivation

* Instantiation
  - New attribute can be added to the instance
  - Same feature type as reference

* Derivation
  - New attribute can be added
  - New type object creation
  - Derived type remembers its reference feature
  - New and overloaded behaviors can be defined



Feature Instances

* Every feature is an instance of a CATSpecObject
* It implements several DS interfaces
  - CATISpecObject
  - LifeCycleObject
  - CATIExtendable
  - CATISpecAttrAccess



Feaure extensions

* A feaure is a late type
  - Behavoirs are provided throgh the extension mechanism following
    the Interface/Implementation pattern
  - Inheritance between features is allowed

* New feature will inherit both behaviors and attributes of its super
  type