. Net factory pattern)

Directory

1. Definition
2. UML
3. Participants
4. Example

Definition:

Define an interface for creating objects, but let the subclass determine which class will be instantiated. The factory method delays the instantiation of a class to the subclass.

UML:

Participants:

Product (Project) Role: Define a product interface.

Product (concreteproduct) role: the specific class that implements the product role interface.

Factory role: defines an interface to create a product.

Concretefactory role: a specific class that implements the interface of the factory role.

 

Example

 Code  Using System; Namespace Dofactory. gangoffour. Factory. Structural { /// <Summary>    /// Mainapp startup class for structural   /// Factory method design pattern.    /// </Summary>    Class Mainapp { /// <Summary>      /// Entry point into console application.      /// </Summary>      Static   Void Main (){ // An array of creators Creator [] creators = New Creator [2]; creators [0] = New Concretecreatora (); creators [1] = New Concretecreatorb (); // Iterate over creators and create products        Foreach (Creator In Creators) {product Product = creator. factorymethod (); console. writeline (" Created {0} ", Product. GetType (). Name );} // Wait for user Console. readkey ();}} /// <Summary>    /// The 'product' abstract class    /// </Summary>    Abstract   Class Product {}/// <Summary>    /// A' concreteproduct' class    /// </Summary>    Class Concreteproducta: Product {} /// <Summary>    /// A' concreteproduct' class    /// </Summary>    Class Concreteproductb: Product {} /// <Summary>    /// The 'creator' abstract class    /// </Summary>    Abstract   Class Creator { Public   Abstract Product factorymethod ();} /// <Summary>    /// A' concretecreator' class    /// </Summary>    Class Concretecreatora: Creator { Public   Override Product factorymethod (){ Return   New Concreteproducta ();}} /// <Summary>    /// A' concretecreator' class   /// </Summary>    Class Concretecreatorb: Creator { Public   Override Product factorymethod (){ Return   New Concreteproductb ();}}}

Output:

Created concreteproducta
Created concreteproductb

 

Practical application:

 Code    /// <Summary>      /// Product Interface      /// </Summary>      Public  Interface ICAR { Void Opendoor ();} /// <Summary>      /// BMW      /// </Summary>      Public   Class Baomacar: ICAR { Public   Void Opendoor () {console. writeline (" Open the BMW door ");}} /// <Summary>      /// Audi     /// </Summary>      Public   Class Aodicar: ICAR { Public   Void Opendoor () {console. writeline (" Open Audi door ");}} /// <Summary>      /// The factory interface used to create a car      /// </Summary>      Public   Interface Ifacloud {ICAR create ();} /// <Summary>     /// BMW Factory      /// </Summary>      Public   Class Baomafactory: ifacloud { Public ICAR create (){ Return   New Baomacar ();}} /// <Summary>      /// Audi Factory      /// </Summary>      Public   Class Aodifactory: ifacloud { Public ICAR create (){ Return   New Aodicar ();}} Static   Void Main ( String [] ARGs) {ifactory factory = New Aodifactory (); ICAR car = factory. Create (); car. opendoor (); console. Read ();}

Output:

Open Audi door