名称:Abstract Factory
结构:
意图:
提供一个创建一系列相关或相互依赖对象的接口，而无需指定它们具体的类。
适用性
:
-
一个系统要独立于它的产品的创建、组合和表示时。
-
一个系统要由多个产品系列中的一个来配置时。
-
当你要强调一系列相关的产品对象的设计以便进行联合使用时。
-
当你提供一个产品类库，而只想显示它们的接口而不是实现时。
示例代码：
// Abstract Factory
namespace AbstractFactory_DesignPattern
{
using System;
// These classes could be part of a framework,
// which we will call DP
// ===========================================
abstract class DPDocument
{
abstract public void Dump();
}
abstract class DPWorkspace
{
abstract public void Dump();
}
abstract class DPView
{
abstract public void Dump();
}
abstract class DPFactory
{
abstract public DPDocument CreateDocument();
abstract public DPView CreateView();
abstract public DPWorkspace CreateWorkspace();
}
abstract class DPApplication
{
protected DPDocument doc;
protected DPWorkspace workspace;
protected DPView view;
public void ConstructObjects(DPFactory factory)
{
// Create objects as needed
doc = factory.CreateDocument();
workspace = factory.CreateWorkspace();
view = factory.CreateView();
}
abstract public void Dump();
public void DumpState()
{
if (doc != null) doc.Dump();
if (workspace != null) workspace.Dump();
if (view != null) view.Dump();
}
}
// These classes could be part of an application
class MyApplication : DPApplication
{
MyFactory myFactory = new MyFactory();
override public void Dump()
{
Console.WriteLine("MyApplication exists");
}
public void CreateFamily()
{
MyFactory myFactory = new MyFactory();
ConstructObjects(myFactory);
}
}
class MyDocument : DPDocument
{
public MyDocument()
{
Console.WriteLine("in MyDocument constructor");
}
override public void Dump()
{
Console.WriteLine("MyDocument exists");
}
}
class MyWorkspace : DPWorkspace
{
override public void Dump()
{
Console.WriteLine("MyWorkspace exists");
}
}
class MyView : DPView
{
override public void Dump()
{
Console.WriteLine("MyView exists");
}
}
class MyFactory : DPFactory
{
override public DPDocument CreateDocument()
{
return new MyDocument();
}
override public DPWorkspace CreateWorkspace()
{
return new MyWorkspace();
}
override public DPView CreateView()
{
return new MyView();
}
}
/// <summary>
/// Summary description for Client.
/// </summary>
public class Client
{
public static int Main(string[] args)
{
MyApplication myApplication = new MyApplication();
myApplication.CreateFamily();
myApplication.DumpState();
return 0;
}
}
}