定义:将能够处理同一类请求的对象连成一条链,所提交的请求沿着链传递,链上的对象逐个判断是否有能力处理该请求,
如果能则处理,如果不能则传递给链上的下一个对象。
使用场景:
1.java中,一场机制就是一种责任链模式,一个try可以对应多个catch,当一个不匹配,就会找下一个。
2.javascript中,事件的冒泡和捕获机制。JAVA语言中,事件的处理采用观察者模式。
3.servlet开发中,过滤器的链式处理。
4.struts2中,拦截器的调用也是典型的责任链模式。
场景:
公司里面,请假条的审批流程:
1.如果请求天数小于3天,主任审批
2.如果请假天数大于3天,但小于10天,经理审批
3.如果大于等于10天,小于30天,总经理审批
4.如果大于等于30天,提示拒绝
类图:
实现如下:
请假人:
package com.gcxzflgl.chainOfResp; /** * 封装请假的基本信息 * @author Administrator * */ public class LeaveRequest { private String empName; private int leaveDays; private String reason; public LeaveRequest(String empName, int leaveDays, String reason) { super(); this.empName = empName; this.leaveDays = leaveDays; this.reason = reason; } public String getEmpName() { return empName; } public void setEmpName(String empName) { this.empName = empName; } public int getLeaveDays() { return leaveDays; } public void setLeaveDays(int leaveDays) { this.leaveDays = leaveDays; } public String getReason() { return reason; } public void setReason(String reason) { this.reason = reason; } }
Leader:
package com.gcxzflgl.chainOfResp; /** * 抽象类 * @author Administrator * */ public abstract class Leader { protected String name; protected Leader nextLeader; //责任链上的后继对象 public Leader(String name) { super(); this.name = name; } //设定责任链上的后继对象 public void setNextLeader(Leader nextLeader) { this.nextLeader = nextLeader; } /** * 处理请求的核心的业务方法 * @param request */ public abstract void handleRequest(LeaveRequest request); }
主任:
package com.gcxzflgl.chainOfResp; /** * 主任 * @author Administrator * */ public class Director extends Leader { public Director(String name) { super(name); } @Override public void handleRequest(LeaveRequest request) { if(request.getLeaveDays()<3){ System.out.println("员工:"+request.getEmpName()+"请假,天数:"+request.getLeaveDays()+",理由:"+request.getReason()); System.out.println("主任:"+this.name+",审批通过!"); }else{ if(this.nextLeader!=null){ this.nextLeader.handleRequest(request); } } } }
经理:
package com.gcxzflgl.chainOfResp; /** * 经理 * @author Administrator * */ public class Manager extends Leader { public Manager(String name) { super(name); } @Override public void handleRequest(LeaveRequest request) { if(request.getLeaveDays()<10){ System.out.println("员工:"+request.getEmpName()+"请假,天数:"+request.getLeaveDays()+",理由:"+request.getReason()); System.out.println("经理:"+this.name+",审批通过!"); }else{ if(this.nextLeader!=null){ this.nextLeader.handleRequest(request); } } } }
副总经理:
package com.gcxzflgl.chainOfResp; /** * 副总经理 * @author Administrator * */ public class ViceGeneralManager extends Leader { public ViceGeneralManager(String name) { super(name); } @Override public void handleRequest(LeaveRequest request) { if(request.getLeaveDays()<20){ System.out.println("员工:"+request.getEmpName()+"请假,天数:"+request.getLeaveDays()+",理由:"+request.getReason()); System.out.println("副总经理:"+this.name+",审批通过!"); }else{ if(this.nextLeader!=null){ this.nextLeader.handleRequest(request); } } } }
总经理:
package com.gcxzflgl.chainOfResp; /** * 总经理 * @author Administrator * */ public class GeneralManager extends Leader { public GeneralManager(String name) { super(name); } @Override public void handleRequest(LeaveRequest request) { if(request.getLeaveDays()<30){ System.out.println("员工:"+request.getEmpName()+"请假,天数:"+request.getLeaveDays()+",理由:"+request.getReason()); System.out.println("总经理:"+this.name+",审批通过!"); }else{ System.out.println("莫非"+request.getEmpName()+"想辞职,居然请假"+request.getLeaveDays()+"天!"); } } }
测试:
package com.gcxzflgl.chainOfResp; public class Client { public static void main(String[] args) { Leader a = new Director("张三"); Leader b = new Manager("李四"); Leader b2 = new ViceGeneralManager("李小四"); Leader c = new GeneralManager("王五"); //组织责任链对象的关系 a.setNextLeader(b); b.setNextLeader(b2); b2.setNextLeader(c); //开始请假操作 LeaveRequest req1 = new LeaveRequest("TOM", 15, "回英国老家探亲!"); a.handleRequest(req1); } }