Design Patterns

Transcript

1. 05 March 2014
2. Design Patterns
3. Elements of Reusable Object Oriented Software
4. Eric Gamma “I think patterns as a whole can help people learn object-oriented thinking: how you can leverage polymorphism, design for composition, delegation, balance responsibilities, and provide pluggable behavior.”
5. Richard Helm “The goal for most software developers still remains to design for change — and there the debate is do you do it early or later? In many cases the design should be re-factored, and the patterns provide a target to do this.”
6. Ralph Johnson Most programmers are not hired to write reusable software, except in the sense that the software needs to be usable years later, when requirements change and the world is a different place. On the other hand, they need to know how reusable software works, and our patterns are common in reusable software, so they are still useful for the average programmer to know.
8. Creational Patterns
9. Structural Patterns
10. Behavioral Patterns
11. Creational Patterns Factory Method Abstract Factory Builder Proxy Prototype Singleton Class Object
12. Factory Method (class) “Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.”
13. Chef Abstract Italian Iranian Indian Customer Abstract Italian Iranian Indian Make me Some food AH! @#$!@ Factory Method Mi fanno un po 'di cibo. Sì, signore! زبپ اذغ مارب هفیعض اقآ ،مشچ OK! 0100100011 1100100100
14. Abstract Factory (object) “Provide an interface for creating families of related or dependent objects without specifying their concrete classes.”
15. Where is my the Chef? Hey Chef, make me some food! Italian Indian French Today's cuisine is French! Client Concrete Product Abstract Factory Abstract Factory
16. Builder Pattern Separate the construction of a complex object from its representation so that the same construction process can create different representations.
17. Italian Chef Servant Add: Bread Sauce Pepperoni Tomato Cheese Get: Pitza Add: Dish Dish Cup Glass Get: Pile of Dishes Director Builder
18. Structural Patterns Adapter Adapter Bridge Composite Decorator Facade Flyweight Proxy Class Object
19. Adapter Pattern “Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces.”
20. 1838FAE4F 23AE5DEE AED456EF CA453310 01011 11010 Adapter
21. Bridge Pattern Decouple an abstraction from its implementation so that the two can vary independently.
22. Client Servant Chef May I have PIZZA Here is MENU Margarita Pizza Bridge
23. Composite Pattern “Compose objects into tree structures to represent part-whole hierarchies. Composite let's clients treat individual objects and compositions of objects uniformly.”
24. 1010010001 1100110111 Composite
25. Behavioral Patterns Interpreter Template Method Chain Of Responsibility Command Iterator Mediator Memento Observer State Strategy Visitor Class Object
26. Observer Pattern Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
27. Observer
28. State Pattern Allow an object to alter its behavior when its internal state changes. The object will appear to change its class.
29. I don't know Who you are, YET! State
30. Strategy Pattern Define a family of algorithms, encapsulate each one, and make them interchangeable. Strategy lets the algorithm vary independently from clients that use it.
31. Make me Pizza! :D Strategy
32. Visitor Pattern Represent an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates.
33. Introduce Yourself! Visitor
34. That's it!