What are different types of design patterns?

There are three kinds of design patterns:

Creational patterns:

They are related with how objects and classes are created. While class-creation patterns use inheritance effectively in the instantiation process,while object-creation patterns use delegation to get the job done.

* Abstract Factory groups object factories that have a common theme.
* Builder constructs complex objects by separating construction and representation.
* Factory Method creates objects without specifying the exact object to create.
* Prototype creates objects by cloning an existing object.
* Singleton restricts object creation for a class to only one instance.

Structural patterns:

They are related to class and object composition.This pattern uses inheritance to define new interfaces in order to compose new objects and hence new functionalities.

* Adapter allows classes with incompatible interfaces to work together by wrapping its own interface around that of an already existing class.
* Bridge decouples an abstraction from its implementation so that the two can vary independently.
* Composite composes one-or-more similar objects so that they can be manipulated as one object.
* Decorator dynamically adds/overrides behavior in an existing method of an object.
* Facade provides a simplified interface to a large body of code.
* Flyweight reduces the cost of creating and manipulating a large number of similar objects.
* Proxy provides a placeholder for another object to control access, reduce cost, and reduce complexity.

Behavioral patterns:

These design patterns deal with objects communication. They are specifically concerned with communication between objects.

* Chain of responsibility delegates commands to a chain of processing objects.
* Command creates objects which encapsulate actions and parameters.
* Interpreter implements a specialized language.
* Iterator accesses the elements of an object sequentially without exposing its underlying representation.
* Mediator allows loose coupling between classes by being the only class that has detailed knowledge of their methods.
* Memento provides the ability to restore an object to its previous state (undo).
* Observer is a publish/subscribe pattern which allows a number of observer objects to see an event.
* State allows an object to alter its behavior when its internal state changes.
* Strategy allows one of a family of algorithms to be selected on-the-fly at runtime.
* Template method defines the skeleton of an algorithm as an abstract class, allowing its subclasses to provide concrete behavior.

2 comments :

Anonymous said...

Very nice.

Dinesh Lohia

Anonymous said...

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