This is the last step between modeling our problems and coding our solutions. Each of the elements in our requirements model helps provide us with necessary information that can be used to solve our problem. While the book has the models and design being two separate steps, in many cases you will find that they…
Software patterns are a mechanism for capturing domain knowledge in a way that allows it to be reapplied when a new problem is encountered. In some cases, that knowledge is applied to a new problem within the same domain. In other cases, the domain knowledge captured by a pattern can be applied by analogy to…
The state of the class takes on both active and passive qualities. A passive state is simply the current status of an objects attributes. For example: Consider a GPS app. Your position, direction, etc are just attributes of your class, and thus the passive state. An active state is the status of an object that…
In chapter ten, we looked at data and how to identify classes that were needed from Use Cases. In Chapter 11, we look at Information Exchange through Events. An Event is not the data that has been changed, but rather that information has been exchanged between elements. An Event occurs when information that is exchanged:…
Many times, two or more analysis classes are related to one another in some fashion or another. In UML this is called associations. With Object Oriented code, we often ask if two classes are related or associated through a is-a or has-a type relationship. For example: a car (and object) has a(n) engine (an other…
Operations define the behaviors of the object. While there are lots of different behaviors, they can often be broken down into four main categories. Those that manipulate data often have a set in their function name. Such as setPassword(). Those that check the state of an object usually return a boolean value, and use the…
Attributes help describe a class. They are what help us differentiate from one object and another. Attributes should be relevant to the system that you are building. So two similar objects might have very different attributes based upon how it is used. Consider a College Student Athlete. The data needed for your sports team is…
Some things are easy to identify as a class. For example, if you look around the room, you can find lots of physical objects which can be made into classes. However, in a software environment, this may not always be as easy to identify. So look at the following questions to start to identify what…
