The structural design patterns are more concerned with the ‘On demand’ nature of the system. Now this pattern can be adopted at any stage of the implementation process. Thats the beauty of this approach as you can add dynamic functionality, interfacing is flexible, you can also add sub system to control next level sub systems etc.
To obtain a specific structure of system the structural design patterns is used. Now these ‘On demand’ functionality among other include
- adding dynamic features to a class
- access control
- proxy classes
- light weigh or smaller objects
- bridging
- controller classes to control sub system
The following are the building blocks classified as structural design patterns.
- Decorator
- Adapter
- Bridge
- Composite
- Flyweight
- Facade
- Proxy
They will be defined in details in later sections.