1. Decorator Intent Also known as Wrapper Example: a Text Window
Add additional responsibilities and functionality to objects dynamically
Also known as Wrapper
Example: a Text Window

2. Decorator: Motivation & Application
Subclassing can only add functionality at runtime
Avoid enumerating all possible sub classes
Such as adding a border function to text window.
Use with optional functionality

3. Decorator: Structure
Participants: Component, ConcreteComponent, Decorator, ConcreteDecorator

4. Decorator: Consequences
Positives
More flexibility than static inheritance
Avoids feature laden classes high in hierarchy
Negatives
Lots of little objects
Interface conformance

5. Flyweight
Intent: Use sharing to support large numbers of fine-grained objects efficiently
Origin:
A boxing class which includes fighters weighing less than 112 lb (50 kg) but above 108 lb.
Example: Character in a word processor

6. Flyweight: Motivation & Application
Applications that could benefit from using objects
But the objects are very small and numerous

7. Flyweight: Structure
Participants: Flyweight, ConcreteFlyweight, UnsharedConcreteFlyweight, FlyweightFactory, Client

8. Flyweight: Consequences
Positives
Space saving by using shared objects
Adds functionality to the application
Negatives
Adding processing time of computing extrinsic state
Time can be reduced

9. Any Questions?