Java多态子类函数调用

Question

我很确定我可以在 Stackoverflow 上找到这个问题的答案。不幸的是，我不知道这样做的具体公式。

鉴于以下代码我有问题，我想避免类型检查。 cmets 可能会比我的话更好地描述它。

现在我正在尝试创建一个形状系统，其中每个形状都可以与每个可能的特定形状发生碰撞。 碰撞类：

public class ShapeCollision {
    public static boolean intersects(RectShape rectShape1, RectShape rectShape2) { return true; }

    public static boolean intersects(LineShape lineShape, RectShape rectShape) { return true; }

    public static boolean intersects(RectShape rectShape1, Shape shape) { return true; }

    public static boolean intersects(LineShape lineShape, Shape shape) { return true; }

    public static boolean intersects(Shape shape1, Shape shape2){ return true; }
}

形状类：

public class RectShape extends Shape {
    Vector size;
    public RectShape(Vector pos, Vector size) {
        super(pos);
        this.size = size;
    }
    @Override
    public boolean intersects(IShape shape) {
        return ShapeCollision.intersects(this, shape);
    }
}

public class LineShape extends Shape {
    Vector pos2;
    public LineShape(Vector pos, Vector pos2) {
        super(pos);
        this.pos2 = pos2;
    }
    @Override
    public boolean intersects(IShape shape) {
        return ShapeCollision.intersects(this, shape);
    }
}

public class Shape implements IShape {
    protected Vector pos;
    public Shape(Vector pos) {
        this.pos = pos;
    }
    @Override
    public Vector getPos() {
        return pos;
    }
    @Override
    public void setPos(Vector pos) {
        this.pos = pos;
    }
    @Override
    public void move(Vector movementAmount) {
        pos.add(movementAmount);
    }
    @Override
    public boolean intersects(IShape shape) {
        return ShapeCollision.intersects(this, shape);
    }
}

这对我来说是令人困惑的部分：

Shape rect = new RectShape(new Vector(0,0), new Vector(20,20));
Shape rect2 = new RectShape(new Vector(0,0), new Vector(20,20));
Shape line = new LineShape(new Vector(0,0), new Vector(20,20));

//Since I am saving shape and no specific shapetype, it will pass shape and pick the specific superFunction 
//Right now it calls the intersects(RectShape rectShape1, Shape shape) function due to calling it through the shape variable
rect.intersects(rect2); 
//This calls the intersects(LineShape lineShape, Shape shape) function
rect.intersects(line);    
//This calls the intersects(Shape shape1, Shape shape2) function
ShapeCollision.intersects(rect, line);

如何在不指定变量类型的情况下实现它，即调用带有子类参数的“正确”函数。 （例如：（LineShape lineShape，RectShape rectShape））

我不想在这些函数中进行任何类型检查并专门调用这些函数，而是尽可能使用一些 DesignPatters 或类似的东西:)

Answer 1

如果没有在函数内部进行一些类型检查或在将 Shape 实例传递给函数调用之前对它们进行一些显式转换，则无法实现您想要的。

当然你可以用特定的类来声明对象引用，但我想这并没有什么帮助。