Chapter 1 OBJECT-ORIENTED ANALYSIS AND DESIGN Objectives Describe the book goals and scope Define OOA/D (Object-Oriented Analysis and Design) Illustrate a brief OOA/D example Overview UML and visual agile modeling “Time is a great teacher, but unfortunately it kills all its pupils.” - Hector Berlioz

r4 Applying UML and Patterns Larman’s book is a tool to help developers/students learn core skills in OOA/D. These skills are essential for the creation of well- designed, robust, and maintainable software using OO technologies and languages such as Java or C#. Knowing an object oriented language is necessary but insufficient first step to create object systems. Knowing how to “think in objects” is critical ! Owning a hammer doesn’t make one an architect” (Proverb)

5 Topics and Skills UML notation Requirements analysis Principles and guidelines Patterns Iterative development with an agile Unified Process OOA/D Fig. 1.1 Topics and skills covered in the book. The book illustrates this in the context of long-running case studies that evolve over several iterations.

r6 Analysis Analysis emphasizes an investigation of the problem and requirements, rather than a solution. In software development, we are primarily concerned with two forms of analysis. Requirements Analysis is discovering the requirements that a system must meet in order to be successful. Object-Oriented Analysis is investigating the objects in a domain to discover information important to meet the requirements.

r7 Use Cases Writing Use Cases is not a specifically OO artifact – they are simply written stories. However, they are a best practice for elaborating and understanding requirements.

r8 Design Design emphasizes a conceptual solution that fulfills the requirements, rather than its implementation. Design ideas often exclude low-level or obvious details – obvious to the intended consumers. There are subsets of design, including architectural design, object design, database design. Do the right thing (analysis), and do the thing right (design).

r9 Object-Oriented Analysis and Design (OOA/D) During OOA, the emphasis is on finding and describing the objects (or concepts) in the problem domain, i.e., domain objects. During OOD (or simply object design), the emphasis is on defining software objects and how they collaborate to fulfill the requirements. During OOP (OO Programming) or Implementation, design objects are implemented in a programming language. Implementation is also known as Coding or Construction.

r10 Fig. 1.2 Object-orientation emphasizes representation of objects

r11 Responsibility-Driven Design It is the classical OO design metaphor(symbol) The most important skill in OOA/D is assigning responsibilities to objects. That determines how objects interact and what classes should perform what operations.

r12 Design Patterns Certain tried-and-true solutions to design problems have been expressed as principles of best practice, often in the form of Design Patterns. A Design Pattern is a named problem solution formula that apply excellent design principles.