Advanced ActionScript 3 with Design Patterns

Chapter 4. Singleton Pattern

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• object Instantiation 66

• Singleton Versus Static Members 69

• Building a Simple Singleton 69

• Building a Settings Framework 71

• Summary 74

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The Singleton design pattern is used to limit a class to one instance and provide global access to that instance. In many cases, you need to limit a class to only one instance. Common examples include classes that manage resources that are intrinsically singular such as selection focus, navigation history, and window depth. Consider the case of a class that manages the state of the user’s cursor. Because there is only ever one cursor, you shouldn’t have more than one instance of that class. Another example is a class that loads application ...