Singleton

Singleton is a very well known and used design pattern.

A singleton is a class that can be instantiated only once: this can be very useful when you want a single component to be in charge of all the interaction with a specific piece of hardware.

In boardcore, you can achieve this by extending the Singleton template which you can find in src/shared/.

Interface

The Singleton interface is a template class which exposes a single method:

inline static T* getInstance()

What this method does is:

• If an instance of this class already exists, return that instance.
• If an instance of this class does not exist yet, create and return a new one.

Example

From the Singleton.h comment:

/**
 * WARNING: deriving from this class is not enough to make a singleton,
 * you also have to declare the constructor of your class private!
 */
class Foo : public Singleton<Foo>
{
  private:
      Foo() {} // private constructor
};