TDDB84: Lecture 4 Abstract Factory, Dependency Injection, Composite - PowerPoint PPT Presentation

TDDB84: Lecture 4 Abstract Factory, Dependency Injection, Composite

Abstract factory

Ingredients Pizza Store Clients Fresh Clam NY Mozzarella Cheese Thin Crust Dough I Want a Cheese Pizza Chicago Frozen Clam Parmesan Cheese Thick Crust Dough

Ingredients Pizza Store Clients Fresh Clam NY Mozzarella Cheese Thin Crust Dough I Want a Cheese Pizza Chicago Frozen Clam Parmesan Cheese Thick Crust Dough

Ingredients Pizza Store Clients Fresh Clam NY Mozzarella Cheese I Want a Thin Crust Dough Cheese Pizza Chicago Frozen Clam Parmesan Cheese Thick Crust Dough

Abstract Factory

Concrete Factory Abstract Factory

Concrete Factory Abstract Factory Abstract Products

Clients

Abstract factory: consequences

Abstract factory: consequences + Isolates clients from concrete dependencies

Abstract factory: consequences + Isolates clients from concrete dependencies + Makes interchanging families of products easier

Strategy

Strategy • When related classes only differ in behavior • You need different variants of an algorithm • An algorithm uses data the clients don’t need to know • A class uses conditionals for selecting behavior

Abstract Strategy Factory • When related classes only • A system should be differ in behavior independent of how its products are created • You need different variants • A system should be of an algorithm configured with one of • An algorithm uses data the multiple families of products clients don’t need to know • You want to provide a class • A class uses conditionals library of products, and only expose their interfaces for selecting behavior

Abstract Strategy Factory • When related classes only • A system should be differ in behavior independent of how its products are created • You need different variants • A system should be of an algorithm configured with one of • An algorithm uses data the multiple families of products clients don’t need to know • You want to provide a class • A class uses conditionals library of products, and only expose their interfaces for selecting behavior Behavioral

Abstract Strategy Factory • When related classes only • A system should be differ in behavior independent of how its products are created • You need different variants • A system should be of an algorithm configured with one of • An algorithm uses data the multiple families of products clients don’t need to know • You want to provide a class • A class uses conditionals library of products, and only expose their interfaces for selecting behavior Behavioral Creational

Design principles • Encapsulate what varies • Program to an interface, not to an implementation • Favor composition over inheritance • Classes should be open for extension but closed for modification • Don’t call us, we’ll call you

Design principles • Encapsulate what varies • Program to an interface, not to an implementation • Favor composition over inheritance • Classes should be open for extension but closed for modification • Don’t call us, we’ll call you

Design principles • Encapsulate what varies • Program to an interface, not to an implementation • Favor composition over inheritance • Classes should be open for extension but closed for modification • Don’t call us, we’ll call you

Dependency Injection

ICheesePizza <<ICheese> -cheese > StandardCheesePizza MozzarellaCheese ParmesanCheese IClamPizza <<IClam>> -cheese -clam FancyClamPizza FreshClam FrozenClam NYStyle ChicagoStyle Distinguished by namespaces in C#

DI: How?

DI: How? 1. Declare dependencies as constructor arguments of interface types

DI: How? 1. Declare dependencies as constructor arguments of interface types 2. Register classes (components) in an Inversion-of-Control Container

DI: How? 1. Declare dependencies as constructor arguments of interface types 2. Register classes (components) in an Inversion-of-Control Container 3. Resolve the top-level object from an interface through the Container

1. Dependencies namespace DITest { � public class FancyClamPizza: IClamPizza � { � � private IClam clam; � � private ICheese cheese; � � public FancyClamPizza (IClam clam, ICheese cheese) � � { � � � this.clam = clam; � � � this.cheese = cheese; � � } � � public String ClamType() { � � � return String.Format("fancy {0}",clam); � � } � � public String Describe() { � � � return String.Format("fancy clam pizza with {0} and {1}",ClamType(), cheese); � � } � } }

2. Registration namespace DITest { � public class IoCInstaller: IWindsorInstaller � { � � public void Install(IWindsorContainer container, IConfigurationStore store) � � { � � � container.Register(Classes � � � .FromThisAssembly() � � � .InNamespace("DITest.NYStyle") � � � .WithServiceAllInterfaces()); � � � container.Register (Classes � � � .FromThisAssembly() � � � .AllowMultipleMatches() � � � .InSameNamespaceAs<IoCInstaller>() � � � .WithServiceAllInterfaces()); � � } � } }

2. Registration namespace DITest { � public class IoCInstaller: IWindsorInstaller � { � � public void Install(IWindsorContainer container, IConfigurationStore store) � � { � � � container.Register(Classes � � � .FromThisAssembly() � � � .InNamespace("DITest.NYStyle") � � � .WithServiceAllInterfaces()); � � � container.Register (Classes � � � .FromThisAssembly() � � � .AllowMultipleMatches() � � � .InSameNamespaceAs<IoCInstaller>() � � � .WithServiceAllInterfaces()); � � } � } } Castle Windsor, http://www.castleproject.org

3. Resolution � � � var container = new WindsorContainer(); � � � // adds and configures all components using WindsorInstallers from executing assembly � � � container.Install(FromAssembly.This()); � � � // instantiate and configure root component and all its dependencies and their dependencies and... � � � var p = container.Resolve<ICheesePizza>(); � � � Console.WriteLine (p.Describe ());

Demo

Design principles • Encapsulate what varies • Program to an interface, not to an implementation • Favor composition over inheritance • Classes should be open for extension but closed for modification • Don’t call us, we’ll call you • Depend on abstractions, do not depend on concrete classes

Composite

Ok, now we’re done with menus, coffees and pizzas. Right?

Ok, now we’re done with menus, coffees and pizzas. Right? Right?

Ok, now we’re done with menus, coffees and pizzas. Right? Right? No.

Ok, now we’re done with menus, coffees and pizzas. Right? Right? No. We need a desert menu!

We need a coffee menu! Ok, now we’re done with menus, coffees and pizzas. Right? Right? No. We need a desert menu!

Waiter

Waiter printMenu()

Waiter printMenu() Coffee menu Dark roast Tea Espresso Coffee

Waiter printMenu() Breakfast menu Spam, Coffee Coffee Ham & Spam & Eggs & spam & menu menu eggs eggs spam eggs Dark roast Tea Espresso Coffee

Waiter printMenu() Pizza Breakfast menu menu Spam, Coffee Clam Cheese Coffee Coffee Ham & Spam & Eggs & spam & menu Pizza Pizza menu menu eggs eggs spam eggs Dark roast Tea Espresso Coffee

Waiter Diner printMenu() menu Pizza Breakfast menu menu Spam, Coffee Clam Cheese Coffee Coffee Ham & Spam & Eggs & spam & menu Pizza Pizza menu menu eggs eggs spam eggs Dark roast Tea Espresso Coffee

Waiter print() Diner printMenu() menu Pizza Breakfast menu menu Spam, Coffee Clam Cheese Coffee Coffee Ham & Spam & Eggs & spam & menu Pizza Pizza menu menu eggs eggs spam eggs Dark roast Tea Espresso Coffee

Waiter print() Diner printMenu() menu print() Pizza Breakfast menu menu Spam, Coffee Clam Cheese Coffee Coffee Ham & Spam & Eggs & spam & menu Pizza Pizza menu menu eggs eggs spam eggs Dark roast Tea Espresso Coffee

Waiter print() Diner printMenu() menu print() Pizza Breakfast menu menu Spam, print() Coffee Clam Cheese Coffee Coffee Ham & Spam & Eggs & spam & menu Pizza Pizza menu menu eggs eggs spam eggs Dark roast Tea Espresso Coffee

Waiter print() Diner printMenu() menu print() Pizza Breakfast menu menu Spam, print() Coffee Clam Cheese Coffee Coffee Ham & Spam & Eggs & spam & menu Pizza Pizza menu menu eggs eggs spam eggs Dark print() roast Tea Espresso Coffee

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