设计模式之适配器模式

适配器模式定义：将一个类的接口，转换成客户期望的另一个接口。适配器让原本接口不兼容的类可以合作无间。

简单定义：封装对象，并提供不同的接口。

简单例子：

鸭子接口：

package headfirst.adapter.ducks;

public interface Duck {
public void quack();
public void fly();
}

具体鸭子：

package headfirst.adapter.ducks;

public class MallardDuck implements Duck {
public void quack() {
System.out.println("Quack");
}

public void fly() {
System.out.println("I'm flying");
}
}

火鸡接口：

package headfirst.adapter.ducks;

public interface Turkey {
public void gobble();
public void fly();
}

具体火鸡：

package headfirst.adapter.ducks;

public class WildTurkey implements Turkey {
public void gobble() {
System.out.println("Gobble gobble");
}

public void fly() {
System.out.println("I'm flying a short distance");
}
}

将火鸡适配成鸭子：

package headfirst.adapter.ducks;

public class TurkeyAdapter implements Duck {
Turkey turkey;

public TurkeyAdapter(Turkey turkey) {
this.turkey = turkey;
}

public void quack() {
turkey.gobble();
}

public void fly() {
for(int i=0; i < 5; i++) {
turkey.fly();
}
}
}

测试：

package headfirst.adapter.ducks;

public class DuckTestDrive {
public static void main(String[] args) {
MallardDuck duck = new MallardDuck();

WildTurkey turkey = new WildTurkey();
Duck turkeyAdapter = new TurkeyAdapter(turkey);

System.out.println("The Turkey says...");
turkey.gobble();
turkey.fly();

System.out.println("\nThe Duck says...");
testDuck(duck);

System.out.println("\nThe TurkeyAdapter says...");
testDuck(turkeyAdapter);
}

static void testDuck(Duck duck) {
duck.quack();
duck.fly();
}
}

输出：

The Turkey says...
Gobble gobble
I'm flying a short distance

The Duck says...
Quack
I'm flying

The TurkeyAdapter says...
Gobble gobble
I'm flying a short distance
I'm flying a short distance
I'm flying a short distance
I'm flying a short distance
I'm flying a short distance