Question

I’m making a game in java, and I’m stuck with a design problem.
My resources (images, animations, sounds) are stored in a few HashMaps, one for each type of resource. These (static) hashmaps are located in a static class called “Res”. When an entity needs a resource, it accesses one of the hashmaps of the global class, and if the resource doesn’t exist, it is automatically loaded.

    static Map<String, Sprite> sprites = new HashMap<>();
static Map<String, BufferedImage> images = new HashMap<>();
static Map<String, Clip> sounds = new HashMap<>();
static Map<String, Font> fonts = new HashMap<>();

My question is: Is this design good enough? I’ve read that static functions are bad practice, but do I have to pass an instance of the class “Res” everytime then? Or are there other alternatives? And also, is this resource management system good practice?
Thanks in advance!

Answer 1

Use Singleton to maintain all of the resources instead of these static functions.

public class ResourceSingleton {
    private Map<String, Sprite> sprites = new HashMap<>();
    private Map<String, BufferedImage> images = new HashMap<>();
    private <String, Clip> sounds = new HashMap<>();
    private <String, Font> fonts = new HashMap<>();     

    public Map getSprites()
    {return sprites;}

    public void setSprites(Map<String,Sprite> sprites)
    { this.sprites = sprites; } 

    //generate other getter setter

    // Private constructor prevents instantiation from other classes
    private ResourceSingleton() { }


    private static class SingletonHolder { 
            public static final Singleton instance = new Singleton();
            //populate your resource here.
    }

    public static ResourceSingleton getInstance() {
            return SingletonHolder.instance;
    }

}

To use the resource you can just call

ResourceSingleton res = ResourceSingleton.getInstance();
Sprite firstSprite = res.getSprites().get("firstSprite");