ITEC 370

Lecture 11Design

Design

Review

• Questions?• Today!

– Rough draft of your SRS document– Introduction, Features (Functional / Non-functional),

Interfaces– Prepare for presenting the next week

• UML– UML by shotgun approach– What are the reasons for using UML?– What are some dangers of using UML?– How do you think UML will be used in your project?

Design

Objectives

• Design patterns– Not by shotgun approach

Design

Design patterns

• What is a design pattern in your own words?

• What are they used for?• Have you ever used one before?– How useful was it?

Design

Definition

In software engineering, a design pattern is a general reusable solution to a commonly occurring problem within a given context in software design. A design pattern is not a finished design that can be transformed directly into code. It is a description or template for how to solve a problem that can be used in many different situations. Patterns areformalized best practices that the programmer must implement themselves in the application.

wikipedia

Design

Example pattern

• Command– Used to call methods on classes

• Parts– Client– Invoker– Receiver

• Goal– Middleman that handles details between

client and functionality– What are some of the uses of this?

Design

Graphically

Design

Example

• mQuiz–Mobile quiz app– Quick, functional system– Used for a couple of semesters in ITEC 120

Design

Code

• How did the command pattern was used to help build this system

• Available on sourceforge if you want it

Design

Review

• Design patterns• Command pattern– Definition– Example