AVNEESH KUMAR - C# Design Patterns

Wednesday, June 06, 2007

In software development, a design Pattern describes a general solution to a design problem that recurs repeatedly in many projects. Software designers adapt the Pattern solution to their specific project. Patterns use a formal approach to describing a design problem, its proposed solution, and any other factors that might affect the problem or the solution. A successful Pattern should have established itself as leading to a good solution in three previous projects or situations.

Here are 3 categories of the Patterns involved in software designing...

1) Creational Patterns

Abstract factory pattern: centralize decision of what factory to instantiate

Factory method pattern: centralize creation of an object of a specific type choosing one of several implementations

Anonymous subroutine objects pattern

Builder pattern: separate the construction of a complex object from its representation

Lazy initialization pattern: tactic of delaying the creation of an object, the calculation of a value, or some other expensive process until the needed first time

Prototype pattern: used when the inherent cost of creating a new object in the standard way (e.g., using the 'new' keyword) is prohibitively expensive

Singleton pattern: restrict instantiation of a class to one object

2) Structural Patterns

Adapter pattern: 'adapts' one interface for a class into one that a client expects

Composite pattern: a tree structure of objects where every object has the same interface

Aggregate pattern: a version of the Composite pattern with methods for aggregation of children

Bridge pattern: decouple an abstraction from its implementation so that the two can vary independently

Container pattern: create objects for the sole purpose of holding other objects and managing them

Decorator pattern: add additional functionality to a class at run time where subclassing would result in an exponential rise of new classes

Extensibility pattern: aka. Framework - hide complex code behind a simple interface

Facade pattern: create a simplified interface of an existing interface to ease usage for common tasks

Flyweight pattern: a high quantity of objects share a common properties object to save space

Proxy pattern: a class functioning as an interface to another thing

Pipes and filters: a chain of processes where the output of each process is the input of the next

Private class data pattern: restrict accessor/mutator access

3) Behavioral Patterns

Chain of responsibility pattern: Command objects are handled or passed on to other objects by logic-containing processing objects

Command pattern: Command objects encapsulate an action and its parameters

Interpreter pattern: Implement a specialized computer language to rapidly solve a specific set of problems

Iterator pattern: Iterators are used to access the elements of an aggregate object sequentially without exposing its underlying representation

Mediator pattern: Provides a unified interface to a set of interfaces in a subsystem

Memento pattern: Provides the ability to restore an object to its previous state (rollback)

Observer pattern: aka Publish/Subscribe or Event Listener. Objects register to observe an event which may be raised by another object

State pattern: A clean way for an object to partially change its type at run time

Strategy pattern: Algorithms can be selected on the fly

Template method pattern: Describes the program skeleton of a program

Visitor pattern: A way to separate an algorithm from an object

Single-serving visitor pattern: Optimise the implementation of a visitor that is allocated, used only once, and then deleted

Hierarchical visitor pattern: Provide a way to visit every node in a hierarchical data structure such as a tree

Look for subsequent posts for clarification of each one from C# point of view...

Cheers!!!

.Net | C#

posted on Wednesday, June 06, 2007 4:09:07 PM (Central Standard Time, UTC-06:00)

Tuesday, August 26, 2008 5:08:28 AM (Central Standard Time, UTC-06:00)

Hi. You can find generic, ready-to-use implementation of CoR pattern for .NET here: http://nchain.sourceforge.net .

plpasta | plpastaAT NOSPAMgmail dot com

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