Object Oriented Design Lec 1

Object-oriented programming is a method of implementation in which programs are organized as cooperative collections of objects, each of which represents an instance of some class, and whose classes are all members of a hierarchy of classes united via inheritance relationships.

• 1. Object-oriented programming uses objects, not algorithms, as its fundamental logical building blocks (the “part of” hierarchy); 
• 2. each object is an instance of some class;
• 3. classes may be related to one another via inheritance relationships

• 1. It supports objects that are data abstractions with an interface of named operations and a hidden local state.
• 2. Objects have an associated type [class].
• 3. Types [classes] may inherit attributes from supertypes [superclasses].

Object Oriented design is a method of design, encompassing the process of object oriented decomposition and a notation for depicting both logical and physical as well as static and dynamic models of the system under design.

• 1. leads to an object-oriented decomposition
• 2. uses different notations to express different models of the logical (class and object structure) and physical (module and process architecture) design of a system, in addition to the static and dynamic aspects of the system.

• Appropriately supports the OO design process
• A method of analysis that examines the requirements from the perspective of the classes and objects found in the domain.
• 

• Abstraction
• Encapsulation
• Modularity 
• Hierarchy

• Typing 
• Concurrency
• Persistence