Source vs. Filter streams

• All Filter streams implement the Decorator design pattern and can therefore be connected to any source stream.

• This is a very neat and useful example of how a design pattern actually allows extended functionallity and resuability.

• Note however, that a decorator can never be used on its own. It will always be dependant on its enclosed component (or stream in our case) for receiving/sending the actual bytes/chars.

• Decorators can also be chained on to another – or recursively applied. This is called chaining