Object-oriented Analysis

Object-oriented Analysis (OOA) is the development of software specifications that describe the required system in terms of interacting objects as opposed to the traditional data or functional views of systems. Each object expresses the functionality and interactions of its “real-world” equivalent.

An object is a representation of a real-life entity or abstraction. For example, objects in a flight reservation system might include:

• an airplane
• an airline flight
• an icon on a screen
• a full screen with which a travel agent interacts.

OOA specifies the structure and the behaviour of the object - these comprise the requirements of that object.

Different types of models are required to specify the requirements of the objects. The information or object model contains the definition of objects in the system, which includes: the object name, the object attributes, and object relationships to other objects.

The behaviour or state model describes the behaviour of the objects in terms of the states the object exists in, the transitions allowed between objects, and the events that cause objects to change states. These models can be created and maintained using CASE tools that support representation of objects and object behaviour.

OOA views the world as objects with data structures and behaviours and events that trigger operations, or object behaviour changes, that change the state of objects. The idea that a system can be viewed as a population of interacting objects, each of which is an atomic bundle of data and functionality, is the foundation of object technology and provides an attractive alternative for the development of complex systems.

This is a radical departure from prior methods of requirements specification, such as functional decomposition and structured analysis and design.

See also Object-oriented Design.

This feature together with the discussions on OOSD/OOD/OOP are available as an Acrobat pdf for download.

[Carnegie Mellon, Software Engineering Institute]