Posts tagged design patterns

Decorator – Attach additional reponsibilities to an object dynamically. Decorators provide a flexible alternative to subclassing for extending functionality.

CName: Wrap

OO Principles:

• Classes should be open for extension but close for modification.

Bullet Points:

• Inheritance is one form of extension, but not necessarily the best way to achieve flexibility in our designs.
• In our designs we should allow behavior to be extended without the need to modify existing code.
• Compostion and delegation can often be used to add new behaviors at runtime. (more…)

The Strategy Pattern defines a family of algorithms, encapsulates each once, and makes them interchangebale. Strategy lets the algorithm vary independently from clients that use it.

OO Principles:

• Encapsulate what varies.
• Favor compostion ove inheritence.
• Program to interface, not implementation.

Bullet Points:

• Knowing the OO basics does not make you a great OO designer.
• Good OO designs are reusable, extensible and maitainable.
• Patterns are proven object-oriented experience.
• Patterns don’t give you code, the give you general solution to design problems. You apply them to your specific application. (more…)