Design Pattern (iii): Abstract Factory

First, the definition

The factory method mentioned earlier. Each factory corresponds to a class of products. Abstract Factory is the factory method is no longer for a product, but a number of different types of products.

The difference between the factory method and the abstract method-manual drawing, the word is a bit ugly.

Second, examples

Service type interface: can also be likened to "series A", Specific products: WCF, BL

  Public InterfaceIService {} Public classWcf:iservice { PublicWCF () {Console.WriteLine ("WCF services."); }    }     Public classBl:iservice { PublicBL () {Console.WriteLine ("BL service."); }    }

Push Service interface: can also be likened to "Series B": There are QQ and email products

  Public InterfaceIpush {} Public classQq:ipush { PublicQQ () {Console.WriteLine ("QQ push service."); }    }     Public classEmail:ipush { PublicEmail () {Console.WriteLine ("email push service."); }    }

Factory Interface: Create two series of products: Series A and Series B

 Public Abstract class Factorybuilder    {        publicabstract  iservice creatservice ();          Public Abstract Ipush Creatpush ();    }

Factory A: Create a WCF service and QQ push

 Public class Wcf_qqpushfactory:factorybuilder    {               publicoverride  iservice creatservice ()        {            returnNew  WCF ();        }          Public Override Ipush Creatpush ()        {            returnnew  QQ ();        }    }

Factory B: Create BL service and email push

 Public class Bl_emailfactory:factorybuilder    {                     publicoverride  iservice creatservice ()        {            returnNew  BL ();        }          Public Override Ipush Creatpush ()        {            returnnew  Email ();        }    }

Client calls:

// Abstract Factory New factory3.wcf_qqpushfactory (); fb3. Creatservice (); fb3. Creatpush ();

Iii. Advantages and Disadvantages

Excellent: Each factory can create different products in different series. The instantiation is still deferred to the subclass.

Missing: If a series to increase product or add a series, that ~ ~ Add, modify the place more.

Design patterns to be dialectical use, the right is the best.

Design Pattern (iii): Abstract Factory