3. 抽象工厂模式

抽象工厂：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。 

 

  1 namespace AbstractFactory
  2 {
  3    //日志
  4     public abstract class Log
  5     {
  6         public abstract void WriteLog(Exception ex);
  7     }
  8 //中文日志
  9 public class ChinaLog:Log
 10     {
 11         public override void WriteLog(Exception ex)
 12         {
 13             Console.WriteLine("中文异常信息："+ex.GetException());
 14         }
 15     }
 16 //英文日志
 17 public class EnglishLog:Log
 18     {
 19 
 20         public override void WriteLog(Exception ex)
 21         {
 22             Console.WriteLine("The error is:"+ex.GetException());
 23         }
 24     }
 25 //异常
 26  public abstract class Exception
 27     {
 28         public abstract string GetException();
 29     }
 30 //中文异常
 31 public class ChinaException:Exception
 32     {
 33         public override string GetException()
 34         {
 35             return "错误！";
 36         }
 37     }
 38 //英文异常
 39 public class EnglishException:Exception
 40     {
 41         public override string GetException()
 42         {
 43             return "error!";
 44         }
 45     }
 46 //抽象工厂
 47 public abstract class AbstractFactory
 48     {
 49         public abstract Log CreateLog();
 50         public abstract Exception CreateException();
 51 
 52     }
 53 //中文抽象工厂
 54 public class ChinaFactory:AbstractFactory
 55     {
 56         public override Log CreateLog()
 57         {
 58             return new ChinaLog();
 59         }
 60 
 61         public override Exception CreateException()
 62         {
 63             return new ChinaException();
 64         }
 65     }
 66 //英文抽象工厂
 67 public  class EnglishFactory:AbstractFactory
 68     {
 69         public override Log CreateLog()
 70         {
 71             return new EnglishLog();
 72         }
 73 
 74         public override Exception CreateException()
 75         {
 76             return new EnglishException();
 77         }
 78     }
 79 //客户端
 80 class Program
 81     {
 82         static void Main(string[] args)
 83         {
 84             string assembly=ConfigurationManager.AppSettings["Assembly"];
 85             string instance=ConfigurationManager.AppSettings["Instance"];
 86             AbstractFactory factory = (AbstractFactory)Assembly.Load(assembly).CreateInstance(instance);
 87             Exception ex = factory.CreateException();
 88             Log log = factory.CreateLog();
 89             log.WriteLog(ex);
 90             Console.ReadLine();
 91         }
 92     }
 93 }
 94 
 95 <?xml version="1.0" encoding="utf-8" ?>
 96 <configuration>
 97   <appSettings>
 98     <add key="Assembly" value="AbstractFactory"/>
 99     <add key="Instance" value="AbstractFactory.EnglishFactory"/>
100   </appSettings>
101 </configuration>

 解决了对系列创建的问题，各个子类中可能存在相互依赖的关系，如上面：日志的输出类，依赖于异常返回类。

 这个模式是假设子类不变的情况下使用的，即只有log和exception这两个字类的创建，不会再添加其它的字类，但是可以添加相应的系列如：JapanesseFactory(日文工厂)