StoneBoulder.java

package net.glowstone.generator.objects;

import org.bukkit.DoublePlantSpecies;
import org.bukkit.Material;
import org.bukkit.World;
import org.bukkit.block.Block;
import org.bukkit.block.BlockFace;
import org.bukkit.block.BlockState;
import org.bukkit.material.DoublePlant;
import org.bukkit.material.MaterialData;

import java.util.Random;

public class StoneBoulder {

    private static final Material[] GROUND_TYPES = {Material.GRASS, Material.DIRT, Material.STONE};
    private static final Material[] PLANT_TYPES = {Material.LONG_GRASS, Material.YELLOW_FLOWER, Material.RED_ROSE,
            Material.DOUBLE_PLANT, Material.BROWN_MUSHROOM, Material.RED_MUSHROOM};

    public void generate(World world, Random random, int sourceX, int sourceY, int sourceZ) {
        boolean groundReached = false;
        while (!groundReached && sourceY > 3) {
            final Block block = world.getBlockAt(sourceX, sourceY - 1, sourceZ);
            if (!block.isEmpty()) {
                for (Material mat : GROUND_TYPES) {
                    if (mat == block.getType()) {
                        groundReached = true;
                        sourceY++;
                        break;
                    }
                }
            }
            sourceY--;
        }
        if (groundReached && world.getBlockAt(sourceX, sourceY, sourceZ).isEmpty()) {
            for (int i = 0; i < 3; i++) {
                int radiusX = random.nextInt(2);
                int radiusZ = random.nextInt(2);
                int radiusY = random.nextInt(2);
                float f = (radiusX + radiusZ + radiusY) * 0.333F + 0.5F;
                for (int x = -radiusX; x <= radiusX; x++) {
                    for (int z = -radiusZ; z <= radiusZ; z++) {
                        for (int y = -radiusY; y <= radiusY; y++) {
                            if (x * x + z * z + y * y <= f * f) {
                                final BlockState state = world.getBlockAt(sourceX + x, sourceY + y, sourceZ + z).getState();
                                final Block blockAbove = state.getBlock().getRelative(BlockFace.UP);
                                for (Material mat : PLANT_TYPES) {
                                    if (blockAbove.getType() == mat) {
                                        if (mat == Material.DOUBLE_PLANT && blockAbove.getState().getData() instanceof DoublePlant &&
                                                ((DoublePlant) blockAbove.getState().getData()).getSpecies() == DoublePlantSpecies.PLANT_APEX) {
                                            blockAbove.getRelative(BlockFace.UP).setType(Material.AIR);
                                        }
                                        blockAbove.setType(Material.AIR);
                                        break;
                                    }
                                }
                                state.setType(Material.MOSSY_COBBLESTONE);
                                state.setData(new MaterialData(Material.MOSSY_COBBLESTONE));
                                state.update(true);
                            }
                        }
                    }
                }
                sourceX += random.nextInt(4) - 1;
                sourceZ += random.nextInt(4) - 1;
                sourceY -= random.nextInt(2);
            }
        }
    }
}