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

Object-Oriented Programming in Action

Let's re-examine the shapes example discussed at the beginning of the chapter. How would I implement it in an object-oriented manner? Remember that it has to do the following:

1.	Locate the list of shapes in the database.
2.	Open up the list of shapes.
3.	Sort the list according to some rules.
4.	Display the individual shapes on the monitor.

To solve this in an object-oriented manner, I need to define the objects and the responsibilities they would have.

The objects I would need are:

Class	Responsibilities (Methods)
ShapeDataBase	getCollection —get a specified collection of shapes
Shape (an abstract class)	display —defines interface for Shapes getX —return X location of Shape (used for sorting) getY ...