Thursday 22 September 2016

Design Pattern Step By Step in .Net - 3

Types of design patterns in details

  • Structural design patterns
    • Adapter Match interfaces of different classes
    • Bridge Separates an object’s interface from its implementation
    • Composite A tree structure of simple and composite objects
    • Decorator Add responsibilities to objects dynamically
    • Facade A single class that represents an entire subsystem
    • Flyweight A fine-grained instance used for efficient sharing
    • Private Class Data Restricts accessor/mutator access
    • Proxy An object representing another object

  • Creational design pattern
    • Abstract Factory Creates an instance of several families of classes
    • Builder Separates object construction from its representation
    • Factory Method Creates an instance of several derived classes
    • Object Pool Avoid expensive acquisition and release of resources by recycling objects that are no longer in use
    • Prototype A fully initialized instance to be copied or cloned
    • Singleton A class of which only a single instance can exist

  • Behavioral design patterns
    • Chain of responsibility A way of passing a request between a chain of objects
    • Command Encapsulate a command request as an object
    • Interpreter A way to include language elements in a program
    • Iterator Sequentially access the elements of a collection
    • Mediator Defines simplified communication between classes
    • Memento Capture and restore an object's internal state
    • Null Object Designed to act as a default value of an object
    • Observer A way of notifying change to a number of classes
    • State Alter an object's behavior when its state changes
    • Strategy Encapsulates an algorithm inside a class
    • Template method Defer the exact steps of an algorithm to a subclass
    • Visitor Defines a new operation to a class without change

Popular design pattern

  • Factory Design Pattern
    • Abstract factory
    • Interface factory
    • Concrete factory
  • Lazy Load Design pattern
  • Singleton
  • Repository pattern
  • Prototype

SOLID Principles in C#

Is also a design pattern technique defined in 1990  by Robert C martin.
     S: Single Responsibility Principle (SRP)
     SRP says "Every software module should have only one reason to change".
     This means that every class, or similar structure, in your code should have only one job to do.
     O: Open closed Principle (OSP)
     says "A software module/class is open for extension and closed for modification".
     L: Liskov substitution Principle (LSP)
     It states that "you should be able to use any derived class instead of a parent class and have it behave in the same manner without modification" in short derived classes should be perfectly substitute of their base classes.
     I: Interface Segregation Principle (ISP)
      Developer should not forced to implement one big interface.
     Instead of one fat interface many small interfaces are preferred based on groups of methods, each one serving one sub module.
     D: Dependency Inversion Principle (DIP)
     It states that high-level modules/classes should not depend upon low-level modules/classes. Both should depend upon abstractions.

Software development approaches:
  • Waterfall Model
  • Incremental model (Agile)
  • Iterative Model
  • Spiral approach
  • Vmodel
  • Agile based on Incremental

  • Waterfall Model

  • Incremental model (Agile)

  • Iterative Model

  • Spiral approach

  • Vmodel

  • Agile based on Incremental