인터페이스

인터페이스를 활용하면 객체지향을 조금 더 편리하게 구현할 수 있다.

 

public interface Car {
    void move();
}

public class FastCar implements Car {
    @Override
    public void move() {
        System.out.println("빠르게 달립니다.");
    }
}

public class SnowCar implements Car {
    @Override
    public void move() {
        System.out.println("겨울에 잘 달립니다.");
    }
}

public class SuperCar implements Car {
    @Override
    public void move() {
        System.out.println("슈퍼하게 달립니다.");
    }
}

- 인터페이스를 통해, 다형성과 추상화를 구현한 사례이다. 

 

public interface LivingBeing {
    void grow();
    void reproduce();
    void die();
}

public interface Animal extends LivingBeing {
    void makeSound();
}

public class Dog implements Animal {
    @Override
    public void grow() {
        System.out.println("The dog is growing.");
    }

    @Override
    public void reproduce() {
        System.out.println("The dog is reproducing.");
    }

    @Override
    public void die() {
        System.out.println("The dog has died.");
    }

    @Override
    public void makeSound() {
        System.out.println("Woof woof!");
    }

    // Additional member variables and methods specific to dogs can be defined here.
}

- 인터페이스는 상속도 가능하다.

- 클래스랑 달리, 다중 상속도 가능하다.

 

public interface LivingBeing {
    void grow();
    void reproduce();
    void die();
}

public interface Animal extends LivingBeing {
    void makeSound();
}

public class Dog implements Animal {
    private String name;
    private int age;

    public Dog(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public void grow() {
        System.out.println(name + " the dog is growing.");
    }

    @Override
    public void reproduce() {
        System.out.println(name + " the dog is reproducing.");
    }

    @Override
    public void die() {
        System.out.println(name + " the dog has died.");
    }

    @Override
    public void makeSound() {
        System.out.println(name + " the dog says: Woof woof!");
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

public class Cat implements Animal {
    private String name;
    private int age;

    public Cat(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public void grow() {
        System.out.println(name + " the cat is growing.");
    }

    @Override
    public void reproduce() {
        System.out.println(name + " the cat is reproducing.");
    }

    @Override
    public void die() {
        System.out.println(name + " the cat has died.");
    }

    @Override
    public void makeSound() {
        System.out.println(name + " the cat says: Meow meow!");
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

- 고양이 사례도 추가되었고, 이름과 나이를 직접 접근하지 않고도 캡슐화를 통해 메서드로 파악할 수 있다.