Java - Java의 다형성 예제

interface Cannon{
    void fireCannon();
}
 
interface Missile{
    void fireMissile();
}
 
interface Nuclear{
    void fireNuclear();
}
 
class Cannon1 implements Cannon{
    @Override
    public void fireCannon() {
        System.out.println("1단계 대포 : 펑!");
    }
}
 
class Cannon2 implements Cannon{
    @Override
    public void fireCannon() {
        System.out.println("2단계 대포 : 펑펑!");
    }
}
 
class Cannon3 implements Cannon{
    @Override
    public void fireCannon() {
        System.out.println("3단계 대포 : 콰쾅!");
    }
}
 
class InstallMissile implements Missile{
    @Override
    public void fireMissile() {
        System.out.println("미사일 발사 : 슈~펑!");
    }
}
 
class InstallNuclear implements Nuclear{
    @Override
    public void fireNuclear() {
        System.out.println("핵 미사일 발사 : 초전박살!");
    }
}
 
abstract class Tank{
    private String tName;
    private Cannon cannon;
    private Missile missile;
    private Nuclear nuclear;
    
    Tank(String tName, Cannon cannon){
        this.tName = tName;
        this.cannon = cannon;
    }
    
    Tank(String tName, Cannon cannon, Missile missile){
        this(tName, cannon);
        this.missile = missile;
    }
    
    Tank(String tName, Cannon cannon, Missile missile, Nuclear nuclear){
        this(tName, cannon, missile);
        this.nuclear = nuclear;
    }
    
    public void printTankName() {
        System.out.printf("%s : ", tName);
    }
    
    public void fireCannon() {
        if(cannon == null) {
            return;
        }
        printTankName();
        cannon.fireCannon();
    }
    
    public void fireMissile() {
        if(missile == null) {
            return;
        }
        printTankName();
        missile.fireMissile();
    }
    
    public void fireNuclear() {
        if(nuclear == null) {
            return;
        }
        printTankName();
        nuclear.fireNuclear();
    }
}
 
class Tank1 extends Tank{
    public Tank1(String name, Cannon cannon) {
        super(name, cannon);
    }
}
 
class Tank2 extends Tank{
    public Tank2(String name, Cannon cannon, Missile missile) {
        super(name, cannon, missile);
    }
}
 
class Tank3 extends Tank{
    public Tank3(String name, Cannon cannon, Missile missile, Nuclear nuclear) {
        super(name, cannon, missile, nuclear);
    }
}
 
public class Main{
    public static void main(String[] args) {
        Tank1 tank1 = new Tank1("레벨1 탱크", new Cannon1());
        Tank2 tank2 = new Tank2("레벨2 탱크", new Cannon2(), new InstallMissile());
        Tank3 tank3 = new Tank3("레벨3 탱크", new Cannon3(), new InstallMissile(), new InstallNuclear());
        
        tank1.fireCannon();
        tank1.fireMissile();
        tank1.fireNuclear();
        
        tank2.fireCannon();
        tank2.fireMissile();
        tank2.fireNuclear();
        
        tank3.fireCannon();
        tank3.fireMissile();
        tank3.fireNuclear();
    }
}