Template Method en C#

Template Method es un patrón de diseño de comportamiento que te permite definir el esqueleto de un algoritmo en una clase base y permite a las subclases sobrescribir los pasos sin cambiar la estructura general del algoritmo.

Aprende más sobre el patrón Template Method

Complejidad:

Popularidad:

Ejemplos de uso: El patrón Template Method es muy común en los frameworks C#. Los desarrolladores lo utilizan a menudo para proporcionar a los usuarios de frameworks medios sencillos para extender la funcionalidad estándar utilizando la herencia.

Identificación: El patrón Template Method se puede reconocer por los métodos de comportamiento que ya tienen un comportamiento “por defecto” definido por la clase base.

Ejemplo conceptual

Este ejemplo ilustra la estructura del patrón de diseño Template Method. Se centra en responder las siguientes preguntas:

¿De qué clases se compone?
¿Qué papeles juegan esas clases?
¿De qué forma se relacionan los elementos del patrón?

Program.cs: Ejemplo conceptual

using System;

namespace RefactoringGuru.DesignPatterns.TemplateMethod.Conceptual
{
    // The Abstract Class defines a template method that contains a skeleton of
    // some algorithm, composed of calls to (usually) abstract primitive
    // operations.
    //
    // Concrete subclasses should implement these operations, but leave the
    // template method itself intact.
    abstract class AbstractClass
    {
        // The template method defines the skeleton of an algorithm.
        public void TemplateMethod()
        {
            this.BaseOperation1();
            this.RequiredOperations1();
            this.BaseOperation2();
            this.Hook1();
            this.RequiredOperation2();
            this.BaseOperation3();
            this.Hook2();
        }

        // These operations already have implementations.
        protected void BaseOperation1()
        {
            Console.WriteLine("AbstractClass says: I am doing the bulk of the work");
        }

        protected void BaseOperation2()
        {
            Console.WriteLine("AbstractClass says: But I let subclasses override some operations");
        }

        protected void BaseOperation3()
        {
            Console.WriteLine("AbstractClass says: But I am doing the bulk of the work anyway");
        }
        
        // These operations have to be implemented in subclasses.
        protected abstract void RequiredOperations1();

        protected abstract void RequiredOperation2();
        
        // These are "hooks." Subclasses may override them, but it's not
        // mandatory since the hooks already have default (but empty)
        // implementation. Hooks provide additional extension points in some
        // crucial places of the algorithm.
        protected virtual void Hook1() { }

        protected virtual void Hook2() { }
    }

    // Concrete classes have to implement all abstract operations of the base
    // class. They can also override some operations with a default
    // implementation.
    class ConcreteClass1 : AbstractClass
    {
        protected override void RequiredOperations1()
        {
            Console.WriteLine("ConcreteClass1 says: Implemented Operation1");
        }

        protected override void RequiredOperation2()
        {
            Console.WriteLine("ConcreteClass1 says: Implemented Operation2");
        }
    }

    // Usually, concrete classes override only a fraction of base class'
    // operations.
    class ConcreteClass2 : AbstractClass
    {
        protected override void RequiredOperations1()
        {
            Console.WriteLine("ConcreteClass2 says: Implemented Operation1");
        }

        protected override void RequiredOperation2()
        {
            Console.WriteLine("ConcreteClass2 says: Implemented Operation2");
        }

        protected override void Hook1()
        {
            Console.WriteLine("ConcreteClass2 says: Overridden Hook1");
        }
    }

    class Client
    {
        // The client code calls the template method to execute the algorithm.
        // Client code does not have to know the concrete class of an object it
        // works with, as long as it works with objects through the interface of
        // their base class.
        public static void ClientCode(AbstractClass abstractClass)
        {
            // ...
            abstractClass.TemplateMethod();
            // ...
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Same client code can work with different subclasses:");

            Client.ClientCode(new ConcreteClass1());

            Console.Write("\n");
            
            Console.WriteLine("Same client code can work with different subclasses:");
            Client.ClientCode(new ConcreteClass2());
        }
    }
}

Output.txt: Resultado de la ejecución

Same client code can work with different subclasses:
AbstractClass says: I am doing the bulk of the work
ConcreteClass1 says: Implemented Operation1
AbstractClass says: But I let subclasses override some operations
ConcreteClass1 says: Implemented Operation2
AbstractClass says: But I am doing the bulk of the work anyway

Same client code can work with different subclasses:
AbstractClass says: I am doing the bulk of the work
ConcreteClass2 says: Implemented Operation1
AbstractClass says: But I let subclasses override some operations
ConcreteClass2 says: Overridden Hook1
ConcreteClass2 says: Implemented Operation2
AbstractClass says: But I am doing the bulk of the work anyway

Template Method en C#

Ejemplo conceptual

Program.cs: Ejemplo conceptual

Output.txt: Resultado de la ejecución

Template Method en otros lenguajes