Object-oriented Analysis and Design

Object-oriented Analysis

• The main objective of object-oriented analysis is to develop a series of models that describes the computer software as it works to satisfy a set of customer-defined requirements.
• The intent of object-oriented analysis is to define a set of classes, their relationships and behavior that is relevant to the system being studied.
• Because customer requirements influence the creation of the models, this phase or activity is also called requirements engineering.

Five Principles in Analysis

• The information domain is modeled.
• Module function is described.
• Model behavior is represented.
• The models are partitioned to expose greater detail.
• Early models represent the essence of the problem while later models provide implementation details.

Common Steps of All OOA Methods

• STEP 1: Identify customer requirements for the objectoriented system.
• STEP 2: Select classes and objects using the requirements model as the guideline.
• STEP 3: Identity attributes and operation for each class.
• STEP 4: Define structures and hierarchies that will organize the classes.
• STEP 5: Build the object-relationship model.
• STEP 6: Build the object-behavioral model.
• STEP 7: Review the object-oriented analysis model against requirements and standards.

OO Analysis Main Work Products

• The Requirements Model
• – Use Case Model
• – Supplementary Requirements
• – Glossary
• The Analysis Model
• – Object Model
• – Behavioral Model

Object-oriented Design

• It transforms the analysis model created in object-oriented analysis into a design model that serves as a blueprint for software construction.
• It must describe the specific data organization of attributes and the procedural detail of individual operations.

Five B asic Principles of Design

• Linguistic modular units
• Few interfaces
• Small interfaces/Weak Coupling
• Explicit interface
• Information Hiding

Common Steps to All OOD

• STEP 1: Define the subsystems of the software by determining data-related subsystems (entity design), control-related subsystems (controller design), and human interaction-related subsystems (boundary design). This should be guided by the software architecture of choice.
• STEP 2: Define Class and Object Design
• STEP 3: Define Message Design

OO Design Main Work Products

• Software Architecture
• Data Design
• Interface Design
• Component-level Design
• Deployment Design