Functors

- Sometimes referred to as a function object.

A functor is an object that can be executed like a function.
- It can have state.

'Functors' in Java
- A class may only extend one other class. 
  * The is-a relationship also holds when a class implements an interface.
    + Implementing an interface requires implementing ALL its functions.
    
To be continued...    
    
Splay Trees
- If some data is accessed more than others then a splay tree may be a good choice.

- Data is splayed on operations unless the data is at the root or an empty tree is being inserted to.