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DMTF Tutorial
> CIM > Overview
> Object Orientated Overview
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Object Orientated Overview
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Overview | CIM Specification | CIM Schema | Extension Schema
A prerequisite of understanding and working with CIM is understanding object-oriented modeling. The goal of this section is to deliver a high-level overview of the model and how the various objects of the CIM Schema relate to each other.
CIM is based on an object-oriented model. It is impor tant to recognize that object-oriented modeling is differ ent from object-oriented programming.
Object-oriented modeling is a formal way of representing something in the real world. It draws from traditional set theory and classification theory. The following are some basics to keep in mind with regards to object-oriented modeling:
- Instances are things.
- Properties are attributes.
- Relationships are sets of attributes.
- Classes are types of things.
- Subclasses are subtypes of things.
Note the concept of object-oriented modeling is not limited to computer-related elements. One may use object-oriented modeling to represent many different types of things, from organizational structures, to organic materials, to physical buildings. In the context of CIM, object-oriented modeling is used to model hardware and software elements.
For illustrative purposes the following "Cheeseburger Example" is provided to explain the key concepts of object oriented modeling.
Abstraction: Denotes the essential characteristics of an object that distinguish it from all other kinds of objects and thus provide crisply defined conceptual boundaries.
Example: A Cheeseburger - is good to eat and fun to cook.
Modularity: Decomposition of abstractions into discrete units.
Example: The various “layers” of a Cheeseburger. (e.g., bun, lettuce, ketchup, mayonnaise, burger, cheese, onions, pickles, etc.)
Encapsulation: Process of compartmentalizing the elements of an abstraction that constitute its structure and behavior; encapsulation serves to separate the interface of an abstraction and its implementation.
Example:
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To cook the Cheeseburger: - Is the stove available? Are the burners working? Are the ingredients available?
To eat the Cheeseburger: - Is it made correctly? Is my plate clean?
Hierarchy: A ranking or ordering of abstractions.
Example: A Cheeseburger is really a subclass of a Hamburger with the addition of cheese, which is a subclass of Sandwich, which is in turn a subclass of the Hierarchical superclass Food.
Key Elements:
- Classes – A collection of the definitions of state, behavior, and/or identity.
- Objects– Instances of a class.
- Associations–Relationships between classes or instances of classes.
Dependency
Identity
Aggregation
Composition
And others
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