developerWorks 图书频道: 西游记、设计模式与 IBM WebSphere Portal 应用开发，第 7 章

				
 package com.ibm.designpattern.chap7.responsiblitychain; 

 abstract public class Employee { 
    protected Person boss; 
    protected String name; 
    protected int requestLevel; 
    
    public Employee (String name, Employee boss) { 
        this.name = name; 
        this.boss = boss;   
    } 
    
    public String getName() { 
    	 return name; 
    } 
    
    public void handle(Request request) { 
        if (boss != null) { 
        	 boss.handle(request); 
        } else { 
        	 System.out.println("Nobody can handle the request."); 
        } 
    } 
 }

				
package com.ibm.designpattern.chap7.responsiblitychain; 

public class Manager extends Employee { 
    public Manager(String name, Person boss) { 
        super(name, boss); 
        requestLevel = 1; 
    } 

    public void handle(Request request) { 
        if (requestLevel >= request.getType()) { 
            System.out.println(name 
                + "(Manager) says: I can handle the request"); 
        } else { 
            System.out.println(name 
                + "(Manager) says: I can not handle the request. My boss " 
                + boss.getName() + " will handle it."); 
            super.handle(request); 
        } 
    } 
}

				
package com.ibm.designpattern.chap7.responsiblitychain; 

public class Director extends Employee { 
    public Director(String name, Person boss) { 
        super(name, boss); 
        requestLevel = 2; 
    } 

    public void handle(Request request) { 
        if (requestLevel >= request.getType()) { 
            System.out 
                .println(name + "(Director) says: I can handle the request"); 
        } else { 
            System.out.println(name 
                + "(Director) says: I can not handle the request. My boss " 
                + boss.getName() + " will handle it."); 
            super.handle(request); 
        } 
    } 
}

				
package com.ibm.designpattern.chap7.responsiblitychain; 

public class CEO extends Employee { 
    public CEO (String name, Person boss) { 
        super(name, boss); 
        requestLevel = 3; 
    } 

    public void handle(Request request) { 
        if (requestLevel >= request.getType()) { 
            System.out.println(name + "( CEO) says: I can handle the request"); 
        } else { 
            System.out.println(name 
                    + "( CEO) says: I can not handle the request. My boss " 
                    + boss.getName() + " will handle it."); 
            super.handle(request); 
        } 
    } 
}

				
package com.ibm.designpattern.chap7.responsiblitychain; 

public class Request { 
    public static final int REQUEST_1 = 1; 
    public static final int REQUEST_2 = 2; 
    public static final int REQUEST_3 = 3; 
    
    private int type; 
    
    public Request(int type) { 
        this.type = type; 
    } 
    
    public int getType() { 
        return type;   
    } 
}

				
package com.ibm.designpattern.chap7.responsiblitychain; 

class Client { 
    public static void main(String args[]) { 
        Employee ceo = new CEO("Tom", null); 
        Employee director = new Director("Mike", ceo); 
        Employee manager = new Manager("Jack", director); 
        
        Request req1 = new Request(Request.REQUEST_1); 
        Request req2 = new Request(Request.REQUEST_2); 
        Request req3 = new Request(Request.REQUEST_3); 
        
        System.out.println("Submit req1 to manager");        
        manager.handle(req1); 
        System.out.println(); 
        System.out.println("Submit req2 to manager"); 
        manager.handle(req2); 
        System.out.println(); 
        System.out.println("Submit req3 to manager"); 
        manager.handle(req3); 
    } 
}

				
Submit req1 to manager 
Jack(Manager) says: I  can handle the request 

Submit req2 to manager 
Jack(Manager) says: I can not handle the request. My boss Mike will handle it. 
Mike(Director) says: I can handle the request 

Submit req3 to manager 
Jack(Manager) says: I  can not handle the request. My boss Mike will handle it. 
Mike(Director) says: I can not handle the request. My boss Tom will handle it. 
Tom(VP) says: I can handle the request

				
package com.ibm.journeywest.web.portlet; 

import javax.portlet.ActionRequest; 
import javax.portlet.ActionResponse; 

/** 
* 动作请求处理链接口
* 
* @author Yan Zhi Dong yanzhid@cn.ibm.com 
* 
*/ 
public interface IActionRequestProcessChain { 
     /** 
     * 增加一个动作请求处理链结点
     * 
     * @param chain 
     */ 
     void addChain(IActionRequestProcessChain chain); 

     /** 
     * 处理请求
     * 
     * @param request 
     *            ActionRequest 对象
     * @param response 
     *            ActionResponse 对象
     */ 
     void handleRequest(ActionRequest request, ActionResponse response); 

     /** 
     * 获得下一个链结点
     * 
     * @return 下一个链结点
     */ 
     IActionRequestProcessChain getNextChain(); 
}

				
package com.ibm.journeywest.web.portlet; 

import …

/** 
* 用户管理 portlet 
* 
* @author Yan Zhi Dong yanzhid@cn.ibm.com 
* 
*/ 
public class UserManagementPortlet extends javax.portlet.Generic Portlet { 
     private ActionRequestProcessChain actionRequestProcessChain = null; 

     public void init() throws PortletException { 
         super.init(); 
 // 构造链表
         actionRequestProcessChain = new CheckRequestUserChain(); 
         IActionRequestProcessChain checkUserInputChain = new CheckUserInputChain(); 
         IActionRequestProcessChain checkUserChain = new CheckUserChain(); 
         IActionRequestProcessChain operateUserInformationChain = 
             new OperateUserInformationChain(); 
         actionRequestProcessChain.addChain(checkUserInputChain); 
         checkUserInputChain.addChain(checkUserChain); 
         checkUserChain.addChain(operateUserInformationChain); 
     } 
     …
public void processAction(ActionRequest request, ActionResponse response) 
             throws PortletException, java.io.IOException { 
         ActionRequestWrapper requestWrapper = new ActionRequest Wrapper(request); 
         // 请求流经链
         actionRequestProcessChain.handleRequest(requestWrapper, response); 
         response.setRenderParameter("COMMAND", request.getParameter ("COMMAND")); 
     } 
}