1. PH page 18-24 GoF Singleton p. 127-134
Emanuel Ekstrom

2. Orphans & Adoption
Context: Making a file system. Three objects: Node, File, Directory.
Why do we need to adopt?
Why do we need to orphan?
Who gets an adopt/orphan interface?
So are they all the same?

3. Singleton
Intent:
”Ensure a class only has one instance, and provide a global point of access to it.”

4. Discussion Who needs only one instance?
What is good about a global access point?
Why not global variables instead?

5. How do we make a Singleton? (GoF p. 131)
Constructor protected
Public static Instance() function.
Is this enough?

6. Discussion What if we want to delete a Singleton?
What if a deleted Singleton is called?
Is there a solution to the problem?

7. Subclassing
Problem: Making sure the subclasses are unique and that the clients can access it.
How is this solved?
Drawbacks?