新舊兩個接口，功能類似，舊的接口已漸漸不再使用，如何讓舊接口調整為新接口的樣式呢（方便其他程序調用）？寫一個銜接作用的adapter即可。
如下：Duck和Turkey是兩個接口，他們的功能類似，僅僅是方法的名稱不同。如何把Turkey接口調整成Duck，以方便調用呢？
package javaapplication31;
public class Main {
public static void main(String[] args) {
Duck duck = new MallardDuck();
duck.quack();
Turkey turkey = new WildTurkey();
turkey.gobble();
}
}
interface Duck {
public void quack();
public void fly();
}
class MallardDuck implements Duck {
public void quack() {
System.out.println("Mallard quacked");
}
public void fly() {
System.out.println("Mallard flying");
}
}
interface Turkey {
public void gobble();
public void fly();
}
class WildTurkey implements Turkey {
public void gobble() {
System.out.println("Wild gobbled");
}
public void fly() {
System.out.println("Wild flying");
}
}
新增一個TurkeyAdapter類來完成轉換：
package javaapplication31;
public class Main {
public static void main(String[] args) {
Duck duck = new MallardDuck();
duck.quack();
Turkey turkey = new WildTurkey();
duck = new TurkeyAdapter(turkey);
duck.quack();
}
}
interface Duck {
public void quack();
public void fly();
}
class MallardDuck implements Duck {
public void quack() {
System.out.println("Mallard quacked");
}
public void fly() {
System.out.println("Mallard flying");
}
}
class TurkeyAdapter implements Duck {
Turkey turkey;
TurkeyAdapter(Turkey turkey) {
this.turkey = turkey;
}
public void quack() {
turkey.gobble();
}
public void fly() {
turkey.fly();
}
}
interface Turkey {
public void gobble();
public void fly();
}
class WildTurkey implements Turkey {
public void gobble() {
System.out.println("Wild gobbled");
}
public void fly() {
System.out.println("Wild flying");
}
}
看到這個Adapter，是否想到了Command Pattern中的“裝載器”呢？異曲同工之妙。