Tuesday, December 2, 2008

OOAD Presentation...

My presentation today is about OOAD (Object Oriented Analysis and Design)....
What is OO Analysis & Design?
• Vending Machine Example
– Analysis
• Use case modeling
• Domain modeling
• Behavioral modeling
– Design
• Interaction diagrams
• Refined class diagram
• Concurrency and scheduling

Principles of Modeling
-The choice of what models to create has a profound influence on how a problem is attacked and how a solution is shaped
-Every model may be expressed at different levels of precision
-Best models are connected to reality
-No single model is sufficient.

Abstraction in OOAD

Abstraction is a oops concept. It provides a facility to hide some unimportant information and provide us some information which is important for the client programmers.
Eg: If we consider a car which has lot of parts such as wheels steering dvd player etc.

What is Encapsulation??
Encapsulation is the term given to the process of hiding all the details of an object that do not contribute to its essential characteristics. Ahhh...but what are the essential characteristics of an object? Well, the common definition of an object implies that the only thing that is really essential to an object is the set of methods it can execute. So, encapsulation hides the implementation details of the object and the only thing that remains externally visible is the interface of the object. (i.e.: the set of allmessages the object can respond to). Once an object is encapsulated, its implementation details are not immediately accessible any more. Instead they are packaged and are only indirectly accessible via the interface of the object. The only way to access such an encapsulated object is via message passing: one sends a message to the object, and the object itself selects the method by which it will react to the message, determined by functions.

– Domain level - modeling “real world” objects
– Really: part of requirements engineering
• requirements development = elicitation + analysis +
– Many domain objects will not make into the design
– Domain structures often make poor design structures
– Assigning responsibilities to object
– Taking “illities” (maintainability, reusability, etc.) and
portability into account
– Devising mechanisms

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