MelonDecorator.java

package net.glowstone.generator.decorators.overworld;

import org.bukkit.Chunk;
import org.bukkit.Material;
import org.bukkit.World;
import org.bukkit.block.BlockState;
import org.bukkit.generator.BlockPopulator;
import org.bukkit.material.MaterialData;

import java.util.Random;

public class MelonDecorator extends BlockPopulator {

    @Override
    public void populate(World world, Random random, Chunk source) {
        int sourceX = (source.getX() << 4) + random.nextInt(16);
        int sourceZ = (source.getZ() << 4) + random.nextInt(16);
        int sourceY = random.nextInt(world.getSeaLevel() << 1);

        for (int i = 0; i < 64; i++) {
            int x = sourceX + random.nextInt(8) - random.nextInt(8);
            int z = sourceZ + random.nextInt(8) - random.nextInt(8);
            int y = sourceY + random.nextInt(4) - random.nextInt(4);

            if (world.getBlockAt(x, y, z).getType() == Material.AIR &&
                    world.getBlockAt(x, y - 1, z).getType() == Material.GRASS) {
                final BlockState state = world.getBlockAt(x, y, z).getState();
                state.setType(Material.MELON_BLOCK);
                state.setData(new MaterialData(Material.MELON_BLOCK));
                state.update(true);
            }
        }
    }
}