Builder in C#

Builder in C#

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Separates the construction of a complex object from its representation so that the same construction process can create different representations.

This structural code demonstrates the Builder pattern in which complex objects are created in a step-by-step fashion. The construction process can create different object representations and provides a high level of control over the assembly of the objects.

using System;
using System.Collections;

public class MainApp
{
public static void Main()
{
// Create director and builders
Director director = new Director();

Builder b1 = new ConcreteBuilder1();
Builder b2 = new ConcreteBuilder2();

// Construct two products
director.Construct(b1);
Product p1 = b1.GetResult();
p1.Show();

director.Construct(b2);
Product p2 = b2.GetResult();
p2.Show();

// Wait for user
Console.Read();
}
}

// "Director"
class Director
{
// Builder uses a complex series of steps
public void Construct(Builder builder)
{
builder.BuildPartA();
builder.BuildPartB();
}
}

// "Builder"
abstract class Builder
{
public abstract void BuildPartA();
public abstract void BuildPartB();
public abstract Product GetResult();
}

// "ConcreteBuilder1"
class ConcreteBuilder1 : Builder
{
private Product product = new Product();

public override void BuildPartA()
{
product.Add("PartA");
}

public override void BuildPartB()
{
product.Add("PartB");
}

public override Product GetResult()
{
return product;
}
}

// "ConcreteBuilder2"
class ConcreteBuilder2 : Builder
{
private Product product = new Product();

public override void BuildPartA()
{
product.Add("PartX");
}

public override void BuildPartB()
{
product.Add("PartY");
}

public override Product GetResult()
{
return product;
}
}

// "Product"
class Product
{
ArrayList parts = new ArrayList();

public void Add(string part)
{
parts.Add(part);
}

public void Show()
{
Console.WriteLine("\nProduct Parts -------");
foreach (string part in parts)
Console.WriteLine(part);
}
}

Product Parts ------- PartA PartB Product Parts ------- PartX PartY