java接口应用—策略设计模式
策略模式:定义了一系列算法,将每一种算法封装起来并可以相互替换使用,策略模式让算法独立于使用它的客户应用而独立变化
strategy pattern:The Strategy Pattern defines a family of algorithms,encapsulates each one,and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.
oo设计原则:
1、面向接口编程(面向抽象编程)
2、封装变化
3、多用组合,少用继承
例子:
1 package practice1;
2
3 public class Test9 {
4
5 public static void main(String[] args) {
6 Duck duck=new BlackDuck("黑鸭子", new FlyImpl());
7 duck.fly();
8
9 Duck duck2=new ModeDuck("白鸭子", new NotFlyImpl());
10 duck2.fly();
11 }
12 }
13 class Duck{
14 private String name;
15 private Flyable flyable;//把接口作为属性
16
17 public Duck(String name,Flyable flyable){
18 this.name=name;
19 this.flyable=flyable;
20 }
21 public void fly(){
22 flyable.fly();
23 }
24 }
25
26 class BlackDuck extends Duck{
27
28 public BlackDuck(String name, Flyable flyable) {
29 super(name, flyable);
30 }
31
32 }
33 class ModeDuck extends Duck{
34
35 public ModeDuck(String name, Flyable flyable) {
36 super(name, flyable);
37 }
38
39 }
40 //接口
41 interface Flyable{
42 public void fly();
43 }
44
45 class FlyImpl implements Flyable{
46
47 @Override
48 public void fly() {
49 System.out.println("会飞");
50 }
51
52 }
53
54 class NotFlyImpl implements Flyable{
55
56 @Override
57 public void fly() {
58 System.out.println("不会飞");
59 }
60
61 }