equivalent-exchange-3/src/main/java/com/pahimar/ee3/array/AlchemyArrayRegistry.java

package com.pahimar.ee3.array;

import java.util.SortedSet;
import java.util.TreeSet;

import com.google.common.collect.ImmutableSortedSet;
import com.pahimar.ee3.api.array.AlchemyArray;
import com.pahimar.ee3.util.LoaderHelper;
import com.pahimar.ee3.util.LogHelper;
import cpw.mods.fml.common.Loader;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.MarkerManager;

public class AlchemyArrayRegistry {
    public static final Marker ALCHEMY_ARRAY_MARKER
        = MarkerManager.getMarker("EE3_ALCHEMY_ARRAY", LogHelper.MOD_MARKER);
    private static AlchemyArrayRegistry alchemyArrayRegistry = null;
    private SortedSet<AlchemyArray> registeredAlchemyArrays;

    private AlchemyArrayRegistry() {}

    public static AlchemyArrayRegistry getInstance() {
        if (alchemyArrayRegistry == null) {
            alchemyArrayRegistry = new AlchemyArrayRegistry();
            alchemyArrayRegistry.init();
        }

        return alchemyArrayRegistry;
    }

    private void init() {
        registeredAlchemyArrays = new TreeSet<AlchemyArray>();
    }

    public AlchemyArray getAlchemyArray(int index) {
        if (registeredAlchemyArrays != null) {
            AlchemyArray[] alchemyArrays = new AlchemyArray[0];
            alchemyArrays = registeredAlchemyArrays.toArray(alchemyArrays);

            if (index < alchemyArrays.length) {
                return alchemyArrays[index];
            }
        }

        return null;
    }

    public SortedSet<AlchemyArray> getRegisteredAlchemyArrays() {
        return ImmutableSortedSet.copyOf(registeredAlchemyArrays);
    }

    public boolean registerAlchemyArray(AlchemyArray alchemyArray) {
        if (!registeredAlchemyArrays.contains(alchemyArray)) {
            LogHelper.trace(
                ALCHEMY_ARRAY_MARKER,
                "[{}]: Mod with ID '{}' added alchemy array {}",
                LoaderHelper.getLoaderState(),
                Loader.instance().activeModContainer().getModId(),
                alchemyArray
            );
            return registeredAlchemyArrays.add(alchemyArray);
        }

        return false;
    }
}