java generics T extends Simpletype?

debugcn Published at Dev

BennX

I'd like to write a method, that does return something of a PrimitiveType like float, integer, boolean and also String if possible. I'd like to use generics for it but i stuck and dont find a solution for it. I do need it for a Configparser. Ill use it to get different values from the Config.

Current it des look like this and i know that the switch does not work like this but you get an idea of what id like to do:

public class ConfigurationManager extends XmlReader {
    private final static String FILE_PATH = "config/config.cfg";
    private static Element xml;

    public ConfigurationManager() throws IOException {
        FileHandle handle = Gdx.files.internal(FILE_PATH);
        this.xml = this.parse(handle);
    }

    public Resolution getResolution() {
        Resolution r = new Resolution();
        r.height = xml.getFloat("height");
        r.width = xml.getFloat("width");
        return r;
    }

    public static <T> T getConfig(Class<T> type, String name) {
        if (type.equals(Integer.class)) {
            return type.cast(xml.getInt(name));
        } else if (type.equals(Float.class)) {
            return type.cast(xml.getFloat(name));
        } else if (type.equals(Boolean.class)) {
            return type.cast(xml.getBoolean(name));
        } else if (type.equals(String.class)) {
            return type.cast(xml.get(name));
        }
        throw new AssertionError("Invalid type");
    }
}

Thanks alot

Edwin Dalorzo

Well, I don't think you can do it with primitive types directly, but how about something like this:

public static <T> T getConfig(Class<T> type, String name) {
   if(type.equals(Integer.class)){
    return type.cast(xml.getInteger(name));
   } else if(type.equals(Float.class)){
    return type.cast(xml.getFloat(name));
   } else if(type.equals(Double.class)) {
    return type.cast(xml.getDouble(name));
   } else if(type.equals(String.class)) {
    return type.cast(xml.getString(name));
   } 
   throw new AssertionError("Invalid type");
}

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