Hands-On Design Patterns with C# and .NET Core

The singleton pattern

The singleton pattern is another GoF design pattern that is used to restrict the instantiation of a class to one object. It is used in situations where actions within a system need to be coordinated or access to data needs to be limited. For example, if access to a file needs to be restricted within an application to a single writer, then a singleton could be used to prevent multiple objects from trying to write to the file at the same time. In our scenario, we are going to use a singleton to maintain the collection of books and their inventory.

The value of the singleton pattern is more apparent when it is illustrated using examples. This section will start with a basic class and then go on to identify the different ...