设计模式之--责任链模式
2011-07-29 14:28 java线程例子 阅读(292) 评论(0) 编辑 收藏 举报责任链模式在设计中的应用很多,比如Delphi中对系统对消息的处理,对异常的处理等。只是建立责任链的方式可能不同,有的是建立明确的处理责任链,如消息处理一般是根据控件的Parent来建立责任链条;有的则是暗含一种处理机制,比如Delphi的异常处理(C#也类似)总是从最内层到外,从被调用对象到调用对象这条链进行。下面是责任链模式的一种简单示例:
public abstract class Chain_Successor
{
protected Chain_Successor successor; //保存后继责任者的引用
/// <summary>
/// 处理需求
/// </summary>
/// <param name="request">需要处理的类</param>
public abstract void HandleReqest(Chain_Request request);
/// <summary>
/// 设置后继责任者
/// </summary>
/// <param name="successor">后继责任者</param>
public void SetChain_Successor(Chain_Successor successor)
{
this.successor = successor;
}
}
public class Chain_ConcreateHandleA : Chain_Successor
{
public Chain_ConcreateHandleA()
{
}
public override void HandleReqest(Chain_Request request)
{
//如果自己能处理则处理,否则传递给后继者
if(request.Request_Type==1)
{
System.Windows.Forms.MessageBox.Show(this.ToString()+":"+request.Request_Parameters);
}
else
{
if(this.successor!=null)
successor.HandleReqest(request);
}
}
}
public class Chain_ConcreateHandleB : Chain_Successor
{
public Chain_ConcreateHandleB()
{
}
public override void HandleReqest(Chain_Request request)
{
//如果自己能处理则处理,否则传递给后继者
if(request.Request_Type==2)
{
System.Windows.Forms.MessageBox.Show(this.ToString()+":"+request.Request_Parameters);
}
else
{
if(this.successor!=null)
successor.HandleReqest(request);
}
}
}
public class Chain_ConcreateHandleC : Chain_Successor
{
public Chain_ConcreateHandleC()
{
}
public override void HandleReqest(Chain_Request request)
{
//如果自己能处理则处理,否则传递给后继者
if(request.Request_Type==3)
{
System.Windows.Forms.MessageBox.Show(this.ToString()+":"+request.Request_Parameters);
}
else
{
if(this.successor!=null)
successor.HandleReqest(request);
}
}
}
public class Chain_Request
{
//下面的两个参数可更加具体需要进行构造
private int _Request_type;
private string _Request_parameters;
public Chain_Request(int Request_type,string RequestParameters)
{
this._Request_type = Request_type;
this._Request_parameters = RequestParameters;
}
public int Request_Type
{
get
{
return _Request_type;
}
set
{
_Request_type = value;
}
}
public string Request_Parameters
{
get
{
return _Request_parameters;
}
set
{
_Request_parameters = value;
}
}
}
public class Chain_Client
{
public static void Test()
{
Chain_Successor firstHandler = new Chain_ConcreateHandleA();
Chain_Successor secondHandler = new Chain_ConcreateHandleB();
Chain_Successor ThirdHandler = new Chain_ConcreateHandleC();
firstHandler.SetChain_Successor(secondHandler);
secondHandler.SetChain_Successor(ThirdHandler);
firstHandler.HandleReqest(new Chain_Request(2,"hello,the world!"));
}
}