Connie's Ease Store (A Point-of-Sale Application)
Which you need to know before you dive into the first application: Exactly what is an object? Precisely a class? An object is a person, place, or thing. A class is a explanation that is applicable to each of some range of objects. 1 What are strategies and patterns, and what makes them important? A strategy is a few specific tips that you can use to obtain a specific objective. A pattern is a design of bonding objects, the one which may be used again and again by example. The purpose of approaches and habits is to reduce the amount of time it will require to become effective in building subject models.
FROM THIS CHAPTER
Through this chapter, you are going to learn and apply approaches and habits that in shape within these types of four major activities to build object types: вЂ“ Figuring out system goal and features. Selecting items. Establishing duties. Working out dynamics with cases. and items form a plan, a skeletal system, an company framework that is easy to understand and likely to be considerably more stable as time passes when compared to application organized about data, features, or external interfaces. Relating to classification theory, " In apprehending the real world, [people] constantly employ three ways of organization, which pervade every one of people's thinking: (1) the differentiation of experience in to particular items and their features, e. g., when they distinguish between a shrub and its size and spatial relations to other things, (2) the distinction between whole objects and their aspect parts, at the. g., whenever they contrast a tree having its component branches, and (3) the formation of and the variation between different classes of objects, elizabeth. g., if they form the class of all forest and the class of all pebbles and distinguish between themвЂќ (" Classification Theory, вЂќ Encyclopaedia Britannica, 1986). 1 1Classes
2 Connie's Convenience Retail store
Identifying System Purpose and Features
WelcomeвЂ” to Connie's Convenience Retail store!
Figure 1вЂ“1: Connie's Covenience Store.
IDENTIFYING SYSTEM PURPOSE AND FEATURES
Connie's Convenience Store needs a point-of-sale system. And you are going to build a subject model on her. You could phone Connie a website expert (well, perhaps never to her face; you might not desire her to obtain a big mind about all of this). So why? She knows the business. And she has operating experience in that business, which include experience applying automated devices which (at times purportedly) support and help people run such a business. You see, Connie knows how things operate a convenience store. And she has several actual experience using an automatic point-of-sale system. Where will you begin? Interact with Connie, to identify the purpose and features for the system under consideration.
Discover the purpose of the system
#2. " System PurposeвЂќ Strategy figuring out purpose and features
вЂў Develop an overall purpose affirmation in 25 words or perhaps less. So why this system? For what reason now? вЂў Keep the overall goal, the critical success factor, often before you. вЂў " To support, to assist, to facilitate,... вЂќ
That large, numbered box having a single edge is a approach box. You will see these boxes from time to time, merely when you need these people, within the application chapters. The number in the top left part is the strategy number; it can there for easy reference. This plan is #2. In the app chapters, likely to learn and apply the strategies and patterns while reading them not (necessarily) in sequential purchase. Chapter six lists every strategies, #1 to #148, sequentially.
Determining System Purpose and Features
Connie's Comfort Store several
And now, to Connie. Inquire some purpose-setting questions: (Peter) What are you wanting an automated system to do to suit your needs? (Connie) Perform all the work! End up being my own personal funds machine! (Peter) Dream upon! Really, Connie. What capabilities would assist you to do a better job? (Connie) How about basically sketch a " would like listвЂќ about...