3. a)Three different categories of design patterns are creational, structural and behavioural. Explain what each of these categories mean identifying the differences between them.

b) The Data Access Object (DAO) is an example of a software design pattern. In relation to this pattern, provide the following:

i) The intent of the pattern. ii) A brief description ot a context in which the pattern could be applied. iii) Provide example code that shows the definition of the DAO interface and a class that implements it you may omit the detailed implementation code of the operations.

(c) For each of the following design patterns. give their intent and provide their structural design using an appropriate diagram. In your answer, outline an example use of the pattern.

i) Decorator ii) Proxy