Design Patterns

Dispatcher Pattern

Use a dispatcher if you want to run code in another thread
A dispatcher has two interfaces: one to add code to execute to a list and one to process the list
The dispatcher client interface is an invoke() method to schedule code execution in another thread. It just adds the code to a list.
In the other thread there is a method like invokePending() going through the list and execute the code
The dispatcher implementation can be a singleton to ensure invoke() and invokePending work with the same list

Use if there should be just one object of a class

create a class with only private constructor(s)
users of the object can get it with a static get() interface method from the class
the get method first checks if the object already exists. If not, it creates it with a private constructor and saves it e.g. as a private pointer. Finally it returns the saved object