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Jan 9, 2011

Object Oriented Analysis and Design

A critical fundamental ability in OOA/D is to skillfully assign responsibilities to software components.
Object-oriented analysis and design (OOAD) is a software engineering approach that models a system as a group of interacting objects. Each object represents some entity of interest in the system being modeled, and is characterized by its class, its state (data elements), and its behavior. Various models can be created to show the static structure, dynamic behavior, and run-time deployment of these collaborating objects. There are a number of different notations for representing these models, such as the Unified Modeling Language (UML).

What is Analysis and Design: Analysis emphasizes an investigation of the problem and requirement, rather than a soluation.For example, if a new computerized library information system is desired, how will it be used?
“Analysis” is a board term, best qualified, as in requirements analysis (as investigation of the requirements) or object analysis (an investigation of the domain objects).
Design emphasizes a conceptual solution that fulfills the requirements, rather than its implementation. For example, a description of a database schema and software objects. Ultimately, designs can be implemented. As with analysis, the term is best qualified, as in object design or database design.
Analysis and design have been summarized in the phase do the right thing (analysis), and do the thing right (design).

Object-oriented analysis (OOA) applies object-modeling techniques to analyze the functional requirements for a system. Object-oriented design (OOD) elaborates the analysis models to produce implementation specifications. OOA focuses on what the system does, OOD on how the system does it.

What is Object Oriented Analysis and Design? : During Object Oriented analysis, there is an emphasis on finding and describing the objects- or concepts- in the problem domain. For example, in the case of the library information system, some of the concepts include BOOK.Library and Patron.
During Object-Oriented design, there is an emphasis on defining software objects and how they collaborate to fulfill the requirements. For example, in the library system, a BOOK Software object may have a title attribute and a getChapter method.
Finally, during implementation or object-oriented programming, design objects are implemented, such as a Book class in java.

Domain Concept[BOOK] à BOOK(title)[Visualization of domain concept]->
public class Book{ private String title; public chapter getChapter(int){……..}  }  [representation in an OO programming Language]

Object-oriented analysis (OOA) looks at the problem domain, with the aim of producing a conceptual model of the information that exists in the area being analyzed. Analysis models do not consider any implementation constraints that might exist, such as concurrencydistributionpersistence, or how the system is to be built. Implementation constraints are dealt during object-oriented design (OOD). Analysis is done before the Design

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