java之策略模式

  1 //抽象被裝飾者
  2 public abstract class Component{
  3     private String lsh="output:";//output:生成流水號
  4     public abstract String operation();//抽象方法（包裝）
  5     public String getlsh(){
  6         return lsh;
  7     }
  8 }
  9 //具體被裝飾者
 10 public class detailComponent{
 11     @Override
 12     public String operation(){
 13         return getlsh();
 14     }   
 15 }
 16 //具體裝飾者：常量
 17 public class constant extends Component{
 18     private Component com;
 19     private String cl;        
 20     public constant( Component com,String cl){
 21         this.com=com;           
 22         this.cl=cl;
 23     }
 24     @Override
 25     public String operation(){
 26         return com.operation()+cl;
 27     } 
 28 }
 29 //具體裝飾者：日期
 30 public class time extends Component{
 31   private Component com;
 32   private String rq
 33   public time ( Component com,String rq){
 34     this.rq=rq;
 35    this.com=com;
 36   } 
 37   @Override
 38   public void operation(){
 39    return com.operation()+rq;
 40   }
 41 }
 42 //具體裝飾者：自增數
 43 public class num extends Component{
 44     private String num
 45     public num ( Component com,String num){
 46         this.com=com;
 47         this.num=num;
 48     } 
 49     @Override
 50     public void operation(){
 51         com.operation()+num;
 52 }
 53 }
 54 //測試
 55 public class test {
 56     public static void main(String[] args) {    
 57         //客戶端傳來 三個 規則
 58         String a = "DB";
 59         String b = "YYYY";
 60         String c = "001";
 61         //當前時間 字符串
 62         b = cDate(b);        
 63         Component com = new detailComponent();//創建 被裝飾者
 64         com  = new num (new time(new constant(com,a),b),c);//裝飾 
 65         com.operation();//輸出為：output:DB2020001
 66         Component com2 = new detailComponent();//創建 被裝飾者
 67         c = autoNum(c);//c+1
 68         com2  = new num (new time(new constant(com2,a),b),c);
 69     }
 70     public String autoNum(String c){
 71         StringBuilder strbd = new StringBuilder();
 72         int i,j;
 73         i = Integer.parseInt(c);
 74         i++;
 75         int d = c.length()-Integer.toString(i).length();
 76         j=0;
 77         while(j<d){
 78             j++;
 79             strbd.append("0");
 80         }
 81         strbd.append(i);
 82         return strbd.toString();
 83     }
 84     public String cDate(String b){
 85         SimpleDateFormat dateFormat ;
 86         String str = null;
 87         if(b.length()==8) {
 88             str = "YYYYMMDD";
 89         }
 90         else if(b.length()==6){
 91             str = "YYYYMM";
 92         }
 93         else if(b.length()==4){
 94             str = "YYYY";
 95         }else {
 96             return "error";
 97         }
 98         dateFormat = new SimpleDateFormat(str);
 99         String currentDate = dateFormat.format(new Date());
100         return currentDate;
101     }
102 }