Book.: Object-oriented Analysis and Design with Applications

Author.: Grady Booch

Reference No.: 3725

Quote:

“Both the engineer and the artist must be intimately familiar with the materials of their trade. When we use object-oriented methods to analyze or design a complex software system, our basic building blocks are classes and objects. Since we have thus far provided only informal definitions of these two elements, in this chapter we turn to a detailed study of the nature of classes, objects and their relationships, and along the way provide several rules of thumb for crafting quality abstractions and mechanisms.”

Chapter 3: Classes and Objects

Review:   

Recognizing the nature of an object is an important ability because objects are tangible entity that exhibits some well-defined behavior, but on the other hand, an object from the human perspective is a tangible and/or visible thing, something that may be understood intellectually, or a thing toward which thought or action is directed. Some people are unable to recognize objects, because some objects aren’t classified as humans see in conspicuous terms.

Users are very particular or “choosy” of what they want to work with as an environment. For example, if the user interface is just pure text, the design is ugly, but the program is working perfectly, the user will then leave that program alone and never open it again. Users need both object-oriented systems, not just systems that work perfectly, but appealing in appearance as well.

Now, in the chapter read, classes and objects are indeed mutual because in programming, they are the elements that usually need to be perfected. Processes are perfected, but these classes and objects are usually harder because it has a lot of properties to be filled.

Objects and classes have state, behavior and identity. The element that encompasses all of the usually static properties of the object plus the current, usually dynamic values of each of these properties is called State. It’s simply the abilities of the object. What it can receive and give to users. Behavior is how the object acts and reacts, in terms of its state changes and message passing. It also means that the state can change, according to its abilities, and it depends on the change of the state on how it will behave, acts or reacts. Lastly, Identity is that property of an object which distinguishes it from all other objects. It indicates that an object can be different from others, thus having an identity for itself. It can do a special behavior that others may, may not, can or cannot do.