SINGLETON

CONTENTS

SECTIONS

• Singleton Design Pattern

• Lazy Instantiation

• MonoSingleton

KEYWORDS

• Singleton --> a software engineering concept where a program has global access to a class, that class can only exist ONCE

• Lazy Instantiation --> creates an instance of the singleton class IF it is null

• MonoSingleton --> the ability to turn any class easily into a singleton

• Constraint --> inform the compiler about the capabilities a type argument must have

GAME BASED EXAMPLES

• Singleton Declaration

• Script Communication

• Lazy Instantiation

• Implement MonoSingleton

SINGLETON DESIGN PATTERN

SINGLETON --> a software engineering concept where a program has global access to a class, that class can only exist ONCE

The recommended classes to use the singleton design pattern on is with a programs manager classes

--> Game Manager Class --> Player Manager Class --> UI Manager Class --> Item Manager --> Spawn Manager

Manager classes are the optimal classes to implement the singleton design pattern because they should be the only class of its type within the program.

LAZY INSTANTIATION

LAZY INSTANTIATION --> creates an instance of the singleton class IF it is null

Lazy instantiation is one of the benefits of working with the singleton pattern as it allows a program a failsafe if an instance of a singleton class is null when called. --> But, the best practice is still to make sure the programs singleton classes are not NULL

The downfall to Lazy Instantiation is that if there were values that needed to be assigned within the inspector, those values will not be attached because the class is instantiated on the fly with it's default values.

MONOSINGLETON

MonoSingleton --> the ability to turn any class easily into a singleton

To create a MonoSingleton you need to create a new generic abstract class called MonoSingleton --> will be used as a generic template for all Singletons moving forward in the program

DECLARATION

public abstract class MonoSingleton<T>: MonoBehaviour where T:MonoSingleton<T>

public abstract class --> makes MonoSingleton act as a template

• Cannot attach class to a gameobject

• other classes can inherit & gain all the properties

MonoSingleton<T> : MonoBehaviour --> Defining a generic type of this MonoSingleton

• Inherits from MonoBehaviour

where T: MonoSingleton<T> --> WHERE keyword is a constraint on type parameters

• without constraints, the type argument can be any type