Object Oriented Analysis and Design using the UML CIS 520 Advanced Object-Oriented Design

2 Objectives: Analysis and Design Overview  Review the key analysis and design terms and concepts  Introduce the analysis and design process, including roles, artifacts and workflow  Understand the difference between analysis and design

3 Management Environment Test Analysis & Design Preliminary Iteration(s) Iter. #1 Iter. #2 Iter. #n Iter. #n+1 Iter. #n+2 Iter. #m Iter. #m+1 Configuration & Change Mgmt Requirements ElaborationTransitionInceptionConstruction The purposes of Analysis and Design are:  To transform the requirements into a design of the system to-be.  To evolve a robust architecture for the system.  To adapt the design to match the implementation environment, designing it for performance. Analysis and Design in Context The Analysis and Design workflow is related to other process workflows. The Business Modeling workflow provides an organizational context for the system. The Requirements workflow provides the primary input for Analysis and Design. The Test workflow tests the system designed during Analysis and Design. The Environment workflow develops and maintains supporting artifacts used during Analysis and Design. The Management workflow plans the project and each iteration (described in an Iteration Plan).

4 Supplementary Specification Use-Case Model Design ModelData Model Architecture Document Analysis and Design Analysis and Design Overview Glossary Input Artifacts from requirements workflow

5 Analysis & Design: Outcome The result of analysis and design is a Design Model that serves as an abstraction of the source code the design model acts as a "blueprint" of how the source code is structured and written. the Design Model consists of design classes structured into design packages it also contains descriptions of how objects of these design classes collaborate to perform use cases (use-case realizations). Design activities are centered around the notion of architecture. Production and validation of architecture is the main focus of early design iterations. Architecture is represented by a number of architectural views. capture the major structural design decisions. architectural views are abstractions or simplifications of the entire design, important characteristics are made more visible by leaving details aside.

6 Analysis Versus Design  Analysis  Focus on understanding the problem  Idealized design  Behavior  System structure  A small model  Design  Focus on understanding the solution  Operations and Attributes  Performance  Close to real code  Object lifecycles  A large model

7 Top Down Bottom Up Design Classes Subsystems Use Cases (start in middle) Analysis and Design is not Top-Down or Bottom-Up Middle down Middle up Analysis Classes

8 What Is Architecture?  Software architecture encompasses the set of significant decisions about the organization of a software system  Selection of the structural elements and their interfaces  Behavior as specified in collaborations among those elements  Composition of these structural and behavioral elements into larger subsystems

9 Architecture Constrains Design and Implementation  Architecture involves a set of strategic design decisions, rules or patterns that constrain design and construction CODE Architecture decisions are the most fundamental decisions and changing them will have significant ripple effects. implementation design architecture

10 Analysis and Design Workflow A workflow is a sequence of activities that produces a result of observable value A mere enumeration of all workers, activities and artifacts does not constitute a process. We should describe: the activities a useful result interactions between workers..

11 Analysis and Design Activity Overview For analysis and design, start out with use-case model and supplementary specifications from the Requirements workflow End up with the design model that serves as an abstraction of the source code. Design activities are centered around the notion of architecture. Production and validation of this architecture is the main focus of early design iterations. The architecture is an important vehicle not only for developing a good design model, but also for increasing the quality of any model built during system development.

12 Architect Software Architecture Document Design Model Designer Use-Case Realization Package/ Subsystem Class Database Designer Data Model Architecture Reviewer Design Reviewer Workers and Their Responsibilities

13 Class Diagrams Sequence Diagrams Use Case Collaboration Diagrams What is a Use-Case Realization? Use-Case ModelDesign Model Use CaseUse-Case Realization

14 Iteration nIteration n + 1Iteration n + 2 Use Case A Use-Case Realization A Start of iteration End of iteration Use Case B Use-Case Realization B Use-Case Realization C Use Case C During the analysis and design workflow in an iteration, a use-case will serve as the primary input artifact. By going through the a series of activities defined in the analysis and design workflow, the development team will produce an associated use-case realization that describes how a particular use-case will be realized. Analysis and Design In An Iterative Process