__The__ Buzzword of the 80's and 90's.
The Object Oriented Paradigm is build around a small number of powerful constructs:
- Identity. All objects are uniquely and consistently identified.
- Classification. Objects are instances of a class. All objects of the same class share the same properties.
- Encapsulation. Each class has operations which minipulate instances. An object is therefore both state and behavior.
- Information Hiding. Some parts of a class are innaccessible or private. Interfaces are exposed and the implementation of the interface is hidden.
- Inheritance. The class structure is a directed acyclic graph and child classes default with the same state and behavior of their parent.
- Specilization. The behavior from a parent may be changed in a child's implementation.
- Polymorphism. Child objects can be treated like objects of the parent class. When a method in the interface of the parent class is invoked, the childs implementation is dynamically selected if provided.
- Substutibility. The ability to use a child object where a parent is required. The child can "relax" the preconditions of any ovverrided method and may "constrict" the postconditions after invocation. Doing anything else violates Substutability.
Note: I'm sure I didn't get 'em all.... if someone has an OO book handy.... - ClarkEvans
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