Hide system specific details from an application

I'd like to hide system specific implementations from my application logic. I have chosen the following design (abstract ex开发者_Python百科ample):

public class Mesh implements Drawable {

    @Override
    public void draw(API api) {
        api.render(this);
    }

}

public class OpenGL implements API {

    @Override
    public void render(Drawable drawable) {
        // render drawable, using OpenGL
        // another API implementing class might use DirectX instead
    }

}

Especially the draw(API api) method looks odd to me because the object, the API is passed to, will pass itself to the API.

My (naive) questions are:

1. Is this eventually a Bridge Pattern?
2. Is this approach a proper implementation? (The aim is to hide system specifics.)
3. Would you recommend a better approach?

---

It would be a Bridge Pattern if you passed the API to the constructor of Mesh. On the other hand, it looks similar to the visitor pattern.

This approach may be proper, but I cant tell that from the short snippet. A good design could look like this (which is a simple example of the visitor pattern).

• interface API
  • void render(Mesh mesh);
  • void render(Sprite sprite);
• interface Drawable
  • void draw(API api);
• class Mesh implements Drawable
  • void draw(API api) { api.render(this); }
• class Sprite implements Drawable
  • void draw(API api) { api.render(this); }
• class Group implements Drawable
  • void draw(API api) { for (Drawable e: elements) e.draw(api); }

In this case, this reference passing makes sense, because the implementations of Drawable select the proper (overloaded) method of the API.

Without more information, this is what I would recommend.