CODEWITHSUNDEEP
javalibgdxconstants
Pablo1517
Pablo1517

Reputation: 73

Java - Constants and where to hold them

Ok so I've been reading up on good practices for using constants and enums but I still am confused as to what should I do.

Basically I need to store strings with paths to assets like

"/assets/sprites/ball.png"

and then i need simple name strings like "ball" and I want them to be related to each other. Those strings will be used very often and in different files/packages all across my game's code.

I have a TextureAtlas class that given the name ("ball") already provides me with the actual resource (graphics ready to draw etc). But when I need to load the resource i need to give actual path, not just name. I want to have 1 place where I will have all the constants declared and it would be nice if both the "name" constant and "path" constant were related somehow. So that I don't have to put actual path to the file whenever I want something to use that graphic, instead I want to use constant with the name String.

I hope you can understand what I mean.

Well, I think I could use a map, where key would be the name ("ball") and value would be path ("/assets/ball.png") but I still want to be able to just lets say, write something like this 

Assets.GetSprite(Assets.BALL);

and get an actual resource, or even better

Assets.GetSprite(BALL);

So there is this problem of constants, that I need to define name and corresponding path for my graphics in 1 place and be able to use it from anywhere in the program if I need it. It all needs to be in one place so that whenever I add new resource, like new sound or new sprite to the game I won't have to look all over my program to find the place where it should be manually typed, I want to have that 1 file that I will go over and just add new constant or something like that for that 1 file.

Cheers, Pablo.

Upvotes: 1

Views: 1884

Answers (4)

Tanmay Patil
Tanmay Patil

Reputation: 7057

It might be a good idea to use properties file.

Java Properties

config.properties

ball = /assets/sprites/ball.png
user = /assets/sprites/user.png

To read these values, at the game startup, do following

FileHandle propertiesFileHandle = Gdx.files
            .internal(PROPERTIES_FILE_PATH);
PROPERTIES = new Properties();
try {
    PROPERTIES.load(new BufferedInputStream(propertiesFileHandle.read()));
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}

Now you can share this PROPERTIES object wherever you need.

String ballPath = PROPERTIES.getProperty("ball");

Hope this helps.

Upvotes: 2

troymass
troymass

Reputation: 1062

You can create more complicated enums with parameters. Take a look at the Planet enum in this example http://docs.oracle.com/javase/tutorial/java/javaOO/enum.html or here is an example specific to your project. Remember that are required to create the constructor and the constructor must be private.

public class Asset {

    public enum AssetType {
        BALL("/assets/sprites/ball.png"),
        USER("/assets/sprites/user.png");

        private final String path;

        AssetsType(String path) {
            this.path = path;
        }

        public String getPath() {
            return this.path;
        }
    }

    private AssetType assetType;

    public Asset(AssetType assetType) {
        this.assetType = assetType;
    }

    // ...
}

Upvotes: 1

Thomas Junk
Thomas Junk

Reputation: 5676

I would go for something like this:

 public enum Assets {

     BALL, PLAYER // and so on

 }

 public class Configuration {

     Map<Assets, String> values= new HashMap<Assets, String>();

     public String getPathFor(Assets asset){

         if(!values.containsKey(asset)) throw new IllegalArgumentException();
         return values.get(asset);

     }

     /* Contains further logic to persist configuration */

 }

So you have well defined Assets and a Configuration object, where you store further Information.

Upvotes: 1

Aniket Thakur
Aniket Thakur

Reputation: 68985

What is the problem with the Map? Create a static HashMap and store you mapping there. You can directly get your values from there.

OR

if you simply need mappings where you key and values are constants then you can put them in an interface (Variables are by default public static and final).

Upvotes: 1

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