THE DESIGN PATTERNS JAVA COMPANION 1. Creational Patterns 17 The Factory Pattern 18 How a Facto

THE DESIGN PATTERNS JAVA COMPANION 1. Creational Patterns 17 The Factory Pattern 18 How a Factory Works 18 Sample Code 18 The Two Derived Classes 19 Building the Factory 20 Factory Patterns in Math Computation 22 When to Use a Factory Pattern 24 Thought Questions 25 The Abstract Factory Pattern 26 A GardenMaker Factory 26 How the User Interface Works 28 Consequences of Abstract Factory 30 Thought Questions 30 The Singleton Pattern 31 Throwing the Exception 32 Creating an Instance of the Class 32 Static Classes as Singleton Patterns 33 Creating Singleton Using a Static Method 34