Java访问者模式实现优雅的对象结构处理

public interface Animal {
    void accept(Visitor visitor);
}

@Data
public class Bird implements Animal{
    private String name;
    private String habitat;
    public Bird(String name, String habitat) {
        this.name = name;
        this.habitat = habitat;
    }
    @Override
    public void accept(Visitor visitor) {
        visitor.visitor(this);
    }
}
@Data
public class Cat implements Animal{
    private String sound;
    private int age;
    public Cat(String sound, int age) {
        this.sound = sound;
        this.age = age;
    }
    @Override
    public void accept(Visitor visitor) {
        visitor.visitor(this);
    }
}
@Data
public class Dog implements Animal{
    private String color;
    private int size;
    public Dog(String color, int size) {
        this.color = color;
        this.size = size;
    }
    @Override
    public void accept(Visitor visitor) {
        visitor.visitor(this);
    }
}

public interface Visitor {
    void visitor(Dog dog);
    void visitor(Cat cat);
    void visitor(Bird bird);
}

public class AnimalCountVisitor implements Visitor{
    private int dogCount;
    private int birdCount;
    private int catCount;
    @Override
    public void visitor(Dog dog) {
        dogCount++;
    }
    @Override
    public void visitor(Cat cat) {
        catCount++;
    }
    @Override
    public void visitor(Bird bird) {
        birdCount++;
    }
    public void printCount(){
        System.out.println("狗的个数:"+dogCount);
        System.out.println("猫的个数:"+catCount);
        System.out.println("鸟的个数:"+birdCount);
    }
}
public class AnimalFeatureVisitor implements Visitor {
    private List<String> features;
    public AnimalFeatureVisitor() {
        features = new ArrayList<>();
    }
    @Override
    public void visitor(Dog dog) {
        features.add("Dog:color=" + dog.getColor() + ",size=" + dog.getSize());
    }
    @Override
    public void visitor(Cat cat) {
        features.add("Car:sound=" + cat.getSound() + ",age=" + cat.getAge());
    }
    @Override
    public void visitor(Bird bird) {
        features.add("Bird:name=" + bird.getName() + ",habitat=" + bird.getHabitat());
    }
    public void printFeatures(){
        features.forEach(System.out::println);
    }
}

public class Demo {
    public static void main(String[] args) {
        List<Animal> animals = new ArrayList<>();
        animals.add(new Dog("褐色", 50));
        animals.add(new Dog("白色", 45));
        animals.add(new Cat("喵喵叫", 2));
        animals.add(new Cat("呜呜声", 3));
        animals.add(new Bird("鹦鹉", "森林"));
        animals.add(new Bird("麻雀", "田野"));
        AnimalCountVisitor animalCountVisitor = new AnimalCountVisitor();
        AnimalFeatureVisitor animalFeatureVisitor = new AnimalFeatureVisitor();
        animals.forEach(animal -> {
            animal.accept(animalCountVisitor);
            animal.accept(animalFeatureVisitor);
        });
        animalCountVisitor.printCount();
        animalFeatureVisitor.printFeatures();
    }
}