CSIS 4850: CS Senior Project – Spring 2009
CSIS 4850: Senior Project
Spring 2009
Object-Oriented Design
CSIS 4850: CS Senior Project – Spring 2009
Structured Design vs. OOD (1)
Responsibilities
Design
Component
design
interface
design
architectural
design
data
design
Message
Design
Class/Object Design
Subsystem Design
Design Patterns (domain Objects)
CSIS 4850: CS Senior Project – Spring 2009
Structured Design vs. OOD (2)
- With OO development, think objects (data and operations) rather
than functional procedures (during analysis and design).
- OOD focuses more on the collaboration among objects than data
flow between components of the system.
- OOD exhibits different levels of modularity (subsystem modules
down to individual methods).
- With OOD, system architecture has more to do with object
collaboration than with control flow (as in Structured Design).
- OOD methods provide better support for essential design
concepts - abstraction, modularity, functional independence,
information hiding, and reuse.
CSIS 4850: CS Senior Project – Spring 2009
The Big Picture
OO Analysis
OO Design
Implementation
OO Testing
Deployment
Class
Modeling
Object
Relationship
Modeling
Object
Behavior
Modeling
OO Analysis
OO Design
Implementation
OO Testing
Deployment
Sub-System
Design
Message
Design
Class
Design
Responsibilities
Design
CSIS 4850: CS Senior Project – Spring 2009
Mapping OOA to OOD
Attributes
Operations
Collaborators
Class
Model
Object
Relationships
Use
Cases
Responsibilities
Design
Message
Design
Class/Object Design
Object
Behavior
Model
Subsystem Design
Design Patterns
(domain Objects)
CSIS 4850: CS Senior Project – Spring 2009
Unified Approach to OOD (1)
Responsibilities
Design
OOD Process
Object
Design
System
Design
Message
Design
Class/Object Design
Subsystem Design
CSIS 4850: CS Senior Project – Spring 2009
Unified Approach to OOD (2)
- Read Chapter 22 Handout
- Design is answering the “How” question!
OOA Model
Classes
OOD Model
Objects
Attributes
Data Structures
Methods
Algorithms
Relationships
Messaging
Behavior
Control
CSIS 4850: CS Senior Project – Spring 2009
Major Sections of OO SDD
Other sections and subsection may be added as needed.
Table of Contents
1. Introduction
1.1 Purpose
1.2 Scope
1.3 Definitions, acronyms, and
abbreviations
1.4 References
2. Glossary
3. Use Cases
4. Design Overview
4.1 Introduction
4.2 System Architecture
4.3 System Interfaces
4.4 Constraints and Assumptions
5. System Object Model (System Design)
5.1 Introduction
5.2 Subsystems
5.3 Subsystem Interfaces
6. Object Descriptions (Object Design)
6.1 Objects in Subsystem 1
6.1.1 Object 1
6.1.2 Object 2
6.2 Objects in Subsystem 2
6.2.1 Object 1
6.2.2 Object 2
(use table format as in the SRS)
7. Object collaboration (Process View)
7.1 Objects in Subsystem 1
7.2 Objects in Subsystem 2
8. Data design
9. Dynamic Model
9.1 State Diagrams
9.1.1 State Diagram 1
9.1.2 State Diagram 2
10. Non-functional requirements
11. Supplementary Documentation
CSIS 4850: CS Senior Project – Spring 2009
Step 1: System Design (1)
Partitioning the Analysis Model
- From your SRS description, identify potential subsystems. A
subsystem is a self-contained and highly-independent groups
of classes that define a main function of the system.
- A subsystem has:
- a well-define interface (check use-cases)
- reasonable number of classes
- classes that communicate with each others
- possibly some internal subsystems. (check use-cases)
Consider organizing subsystems in layers for better
management and control (such as GUI layer, computing
subsystems(s) layer, data management layer, etc…).
CSIS 4850: CS Senior Project – Spring 2009
Step 1: System Design (2)
Partitioning the Analysis Model
- In section 5 of the SDD (see slide #8), provide a description
for each subsystem and its interface. (separate table for each
subsystem)
- Provide a collaboration diagram to illustrate interactions
among the subsystems (see figures 22.4 and 22.6 in the
handout). Consider using UML package notation to represent
subsystems.
CSIS 4850: CS Senior Project – Spring 2009
Step 2: Object Design (1)
Here, focus on the detailed design of your objects (attributes and
methods) and their messages.
Apply the following activities of the design process:
1 - Object description
2 - Algorithm design
3 - Data structure design
Make sure to adhere to “information Hiding” and “functional
independence” concepts as you design your objects.
CSIS 4850: CS Senior Project – Spring 2009
Step 2: Object Design (2)
Object Description
For each class in each subsystem, provide object description
that includes interface description and implementation
description.
Interface description is a listing all message that an object of the
class can respond to (i.e., all public methods it provides to its
users).
Implementation description is the internal (hidden) details of the
operations that implement the interface methods (next slide).
Follow the organization in section 6 of the SDD, using table
format for each class.
CSIS 4850: CS Senior Project – Spring 2009
Step 2: Object Design (3)
Algorithm Design
For each operation of the class, provide an algorithm description
as a self-contained module. Consider dividing complex
operations into separate smaller operations, such that each
smaller operation performs a well-defined functions.
Apply stepwise refinement, such that:
- define operation interfaces (list of parameters if any)
- fill-in operation body sections
- refine body details as needed
The level of details of your algorithmic description should be
sufficient enough so that the implementer can translated it to
source code without help from the designer.
CSIS 4850: CS Senior Project – Spring 2009
Step 2: Object Design (4)
Data Structure Design
Define needed data structures of the class (if any) in conjunction
with class operations.
Document your data structures in section 8 of the SDD (see
slide #8). Organize this section (sub-headings) similar to
section 6.
CSIS 4850: CS Senior Project – Spring 2009
Step 2: Object Design (5)
- Create a specification class diagram:
- add classes and relationships needed for modeling the
solution (classes of interest to the developer)
- add more details into individual classes (attributes and
operations details)
- Expand the class diagram in the SRS to include:
- other classes and relationships needed for modeling the
solution (those are classes of interest to you - the
developer)
- details of new classes (attributes and operations)
CSIS 4850: CS Senior Project – Spring 2009
Step 3: Object Collaboration
In section 7 of the SDD (see slide #8), provide description of
collaborations between objects of each subsystems.
Provide a UML diagram similar to figures 22.4 and 22.6 in the
handout to illustrate potential collaborations between objects
of each subsystem.
Notice that collaboration is required when a class cannot fulfill all
of its responsibilities on its own (i.e., the class doesn’t have
method(s) to manipulate its attributes). Most common
collaborations are part-of and has-knowledge-of (see OOA
slides).
CSIS 4850: CS Senior Project – Spring 2009
Milestone #3
Each team is required to submit a printout of the software design
document (SDD) in the class. Due date is Thursday 3/4/2009 in
class.
Make sure that your submission has a cover page with the project
title, group number, names of groups members, class information
(CSIS 4850 – Spring 2009), and submission date.
Feel free to modify any template you choose to fit your project
design description as long as you include the sections outlined on
slide #8. You may reuse your SRS template with the sections
outlined on slide #8.
For sections 6 and 7 of the SDD (slide #8), you can take the tables
from the SRS and expand them to include design details for each
class method and attributes.
CSIS 4850: CS Senior Project – Spring 2009
Final Project Submission
The final submission is complete document that include the
Project Plan, SRS document, SDD, Prototype or
Implementation, and References as major sections.
Add new section for updates made to each of those deliverables
during project development, and a section for potential future
functions of the system.
Review the entire report for flow and consistency.
Due Date: To be decided
Cover page: (project title, group number, names of groups
members, class information, and submission date)