ActionScript 3.0 Design Patterns

Chapter 6. Composite Pattern

What we need to do is learn to work in the system, by which I mean that everybody, every team, every platform, every division, every component is there not for individual competitive profit or recognition, but for contribution to the system as a whole on a win-win basis.

—W. Edwards Deming

In a logically perfect language, there will be one word and no more for every simple object, and everything that is not simple will be expressed by a combination of words, by a combination derived, of course, from the words for the simple things that enter in, one word for each simple component.

—Bertrand Russell

A complex system that works is invariably found to have evolved from a simple system that works.

—John Gaule

What is the Composite Pattern?

The composite pattern provides a robust solution to building complex systems that are made up of several smaller components. The components that make up the system may be individual objects or containers that represent collections of objects. Think of a car as a complex system that is made up of several smaller components. The car contains an engine, body, chassis, seats, tires, etc. For the sake of simplicity, let’s consider a tire as an indivisible or primitive object. A car would be composed of four tires (in reality a tire contains several smaller components such as hubcap, rim, tube, etc.). Similarly, a car contains one steering wheel. However, the engine contains several smaller components such as cylinders, compressor, ...