An example of using an enum to control flower generation for TFC

ExampleFlowers.java

import java.util.*;
import java.util.function.Supplier;
import java.util.stream.Collector;
import java.util.stream.Collectors;

import net.minecraft.world.World;
import net.minecraft.world.chunk.IChunkProvider;
import net.minecraft.world.gen.IChunkGenerator;
import net.minecraftforge.fml.common.IWorldGenerator;
import net.minecraftforge.registries.IForgeRegistry;
import net.minecraftforge.registries.IForgeRegistryEntry;

public class ExampleFlowers
{
    /**
     * This is the flower registry object
     * It is built with some spawn conditions, maybe multiple
     */
    public static class Flower extends IForgeRegistryEntry.Impl<Flower>
    {
        private FlowerSpawnConditions[] conditions;

        public Flower(FlowerSpawnConditions... conditions)
        {
            this.conditions = conditions;
        }

        public boolean hasSpawnCondition(FlowerSpawnConditions condition)
        {
            for (FlowerSpawnConditions c : conditions)
            {
                if (c == condition)
                {
                    return true;
                }
            }
            return false;
        }
    }

    /**
     * These are possible flower spawn conditions
     * For now it should be an enum, but in future this could be dynamic, to allow addons to add to this.
     * (Or they could add to this as an enum with forge's enum manipulation tools (I think))
     */
    public enum FlowerSpawnConditions
    {
        NORMAL,
        CLAY_INDICATOR
    }

    /**
     * A sample world generator that uses the CLAY_INDICATOR flower spawn condition
     */
    public static class WorldGenClay implements IWorldGenerator
    {
        @Override
        public void generate(Random random, int i, int i1, World world, IChunkGenerator iChunkGenerator, IChunkProvider iChunkProvider)
        {
            // Generate clay

            // If clay generation happened:
            List<Flower> validFlowers = TFCRegistries.FLOWERS
                    .getValuesCollection()
                    .stream()
                    .filter(x -> x.hasSpawnCondition(FlowerSpawnConditions.CLAY_INDICATOR))
                    // Also filter on rain / temperature here
                    .collect(Collectors.toList());

            Flower pickedFlower = validFlowers.get(new Random().nextInt(validFlowers.size()));

            // Generate the pickedFlower
        }
    }
}