public void registerMonster(Monster m) {
   if (!monsters.containsKey(m.getId())) {
     monsters.put(m.getId(), m);
   }
 }
  public void spawnNearPlayers() {
    Monster monster = null;
    float prob, rand;
    int count;
    HashMap<String, Player> players = registry.getPlayerManager().getPlayers();
    Player player = null;
    Integer spawnCoolDown = null;
    for (String key : players.keySet()) {
      player = (Player) players.get(key);

      // check for spawning Melvin
      if (registry.currentTime >= nextBossOrcSpawn && nextBossOrcSpawn != 0) {
        // to spawn melvin, player must have 40 AP, be within a range on the map and be on the
        // surface
        if (player.getMapX() >= 2000
            && player.getMapX() <= 5000
            && player.getLevel() >= 10
            && player.getMapY() == this.findFloor(player.getMapX())) {
          spawnBossOrc(player);
        }
      }

      if (spawnCoolDowns.containsKey(key)) {
        spawnCoolDown = spawnCoolDowns.get(key);
      } else {
        spawnCoolDown = new Integer(0);
        spawnCoolDowns.put(key, spawnCoolDown);
      }
      spawnCoolDown--;
      if (spawnCoolDown < 0) {
        int x = player.getMapX();
        int y = player.getMapY();
        int groundLevel = registry.getBlockManager().getLevelByY(y);
        count = -groundLevel;
        try {
          for (String key2 : monsters.keySet()) {
            monster = (Monster) monsters.get(key2);
            if (monster.getCenterPoint().distance(player.getCenterPoint())
                < MonsterManager.mobSpawnRangeMax * 3 / 2) {
              if (monster.getTouchDamage() > 0
                  && !monster.getName().equals("BlueThorn")
                  && !monster.getName().equals("VineThorn")) {
                count++;
              }
            }
          }
        } catch (ConcurrentModificationException concEx) {
          // another thread was trying to modify monsters while iterating
          // we'll continue and the new item can be grabbed on the next update
        }
        if (count < 4) {
          for (MonsterType monsterType : MonsterType.values()) {
            if (count < 4) {
              rand = Rand.getFloat();
              prob = getShouldSpawn(monsterType, groundLevel);
              if (prob > 0.0f) {
                if ((prob - count * spawnRatioDiff) > 0.005f) {
                  prob += -count * spawnRatioDiff;
                } else {
                  prob = 0.005f;
                }
              }
              if (rand <= prob) {
                // System.out.println("spawn near player " + monsterType.name());
                spawn(monsterType.name(), "Roaming", x, y);
                count++;
              }
            }
          }
        } else {
          // EIError.debugMsg("too many to spawn");
          spawnCoolDown = 20;
        }
      }
    }
  }