Design Patterns Explained: A New Perspective on Object-Oriented Design

Encapsulation: the Traditional View and the New View

In my classes on pattern-oriented design, I often ask my students, “Who has heard encapsulation defined as 'data hiding'?” Almost everyone raises his or her hand.

Then I proceed to tell a story about my umbrella. Keep in mind that I live in Seattle, which has a reputation for being wetter than it is, but is still a pretty wet place in the fall, winter, and spring. Here, umbrellas and hooded coats are personal friends!

Let me tell you about my great umbrella. It is large enough to get into! In fact, three or four other people can get in it with me. While we are in it, staying out of the rain, I can move it from one place to another. It has a stereo system to keep me entertained while I stay ...