学习心得：设计模式之Builder模式

实例如下(例子是在网上拷的)

using System;
using System.Collections;

// "Director"
class Director
{
// Methods
public void Construct( Builder builder )
{
builder.BuildPartA();
builder.BuildPartB();
}
}

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

// "ConcreteBuilder1"
class ConcreteBuilder1 : Builder
{
// Fields
private Product product;

// Methods
override public void BuildPartA()
{
product = new Product();
product.Add( "PartA" );
}

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

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

// "ConcreteBuilder2"
class ConcreteBuilder2 : Builder
{
// Fields
private Product product;

// Methods
override public void BuildPartA()
{
product = new Product();
product.Add( "PartX" );
}

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

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

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

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

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

/**//// <summary>
/// Client test
/// </summary>
public class Client
{
public static void Main( string[] args )
{
// 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();
}
}

心理体会：builder模式将一个复杂对象分成了四个模块

Builder:为创建Product对象的各个部件指定抽象接口，定义Product对象的行为规范ConcreteBuilder:实现Builder的接口以构造和装配该产品的各个部件，定义并明确它所创建的表示，并提供一个检索产品的接口。 提供每个部件的具体实现Director:构造一个使用Builer接口的对象，作用在于实现系统的复杂的逻辑业务，逻辑业务是要按顺序，按流程操作的！Product:表示被构造的复杂对象。