1. Component-Level Design
CIS 375
Bruce R. Maxim
UM-Dearborn
11/30/2018

2. Component Definitions - 1
Component is a
Modular
Deployable
replaceable part of a system
Encapsulates implementation
Exposes a set of interfaces
Object-oriented view is that component contains a set of collaborating classes
11/30/2018

3. Component Definitions - 2
Traditional view is that a component (or module) reside in the software and serves one of three roles
Control components coordinate invocation of all other problem domain components
Problem domain components implement a function required by the customer
Infrastructure components are responsible for functions needed to support the processing required in a domain application
11/30/2018

4. Component Definitions - 3
Process-Related view emphasizes building systems out of existing components chosen from a catalog of reusable components as a means of populating the architecture
11/30/2018

5. Structured (Traditional) Component Design
Each block of code has a single entry at the top
Each block of code has a single exit at the bottom
Only three control structures are required:
sequence
condition (if-then-else)
repetition (looping)
Reduces program complexity by enhancing readability, testability, and maintainability
11/30/2018

6. Design Notation: Flowchart
11/30/2018

7. Design Notation: Box Diagram
11/30/2018

8. Box Diagram - Example S1 Case V of Case 1: while C2 do S2 S3 Case 2:
if C3 then
repeat S6 S7
until C1
else S8 S9 C1
11/30/2018

9. Design Notation: Decision Table
Rules
Condition 1 2
Actions
11/30/2018

10. Condition N not numeric T F N <= 1 - N legal N prime Action
Print “N prime” X
Print “N not prime”
Print error message
Print “Good bye”
Input new value for N
Stop
11/30/2018

11. Program Design Language (PDL)
11/30/2018

12. Program Design Language (PDL)
PDL - structured English or pseudocode used to describe processing details
Fixed syntax with keywords providing for representation of all structured constructs, data declarations, and module definitions
Free syntax natural language for describing processing features
Data declaration facilities for simple and complex data structures
Subprogram definition and invocation facilities
11/30/2018

13. Design Notation Assessment Criteria - 1
Modularity
notation supports development of modular software
Overall simplicity
easy to learn, easy to use, easy to write
Ease of editing
easy to modify design representation when changes are necessary
Machine readability
notation can be input directly into a computer-based development system
11/30/2018

14. Design Notation Assessment Criteria - 2
Maintainability
maintenance of the software configuration usually involves maintenance of the procedural design representation
Structure enforcement
enforces the use of structured programming constructs
Automatic processing
allows the designer to verify the correctness and quality of the design
11/30/2018

15. Design Notation Assessment Criteria - 3
Data representation
ability to represent local and global data directly
Logic verification
automatic logic verification improves testing adequacy
Easily converted to program code
makes code generation quicker
11/30/2018