Essentia/api/src/main/java/com/alttd/essentia/EssentiaAPI.java

package com.alttd.essentia;

import org.jetbrains.annotations.ApiStatus;

public interface EssentiaAPI {

    static EssentiaAPI get() {
        return Provider.instance;
    }

    final class Provider {
        private static EssentiaAPI instance = null;

        @ApiStatus.Internal
        static void register(EssentiaAPI instance) {
            if (Provider.instance != null)
                throw new UnsupportedOperationException("Cannot redefine singleton");

            Provider.instance = instance;
        }
    }
}