SAP ABAP Advanced Cookbook

Creating classes based on singleton design pattern

A singleton class is a class that can have only one instance at a time. Any attempt to create a second or more instances should not be allowed. This recipe shows how to create a class based on the singleton design.

Getting ready

We will use the same class created in the last recipe of factory method. We will make few changes to the class so that we can prevent the creation of multiple instances of the class. We will make a copy of the class (program) shown in the previous recipe and modify it. The name of the copy is singleton_class.

How to do it...

For creating a singleton class, follow these steps:

1. Make sure the CREATE PRIVATE addition is included in the singleton class definition.
2. Within the definition, ...