Validatee is an Interface implemented by an Object
that needs to be validated.
In order to validate an object, framework expects either of the two things;
Object being validated is a Validatee itself(it implements Validatee
interface) or a separate Validatee Implementation for this Object is provided.
If a separate Validatee Implementation is provided then an entry needs to be
added to an Implementation File.
ValidationManager is an object that provides Validation functionality,
through its validate( ) function.
ValidationManagerFactory creates
ValidationManager based on the Validation File.
Validation File specifies Validation rules i.e.
which Constraints to apply to which elements.