Stop hasmap going less than 0

So i've got a hashmap, and i'm using it for a currency
and i've got a minus method

Code:java

public void minusCoins(String player, int amount) {
                coins.put(player, coins.get(player) - amount);
                    Bukkit.getLogger().info(player + " had " + Integer.valueOf(amount) + " minused from their account");                               
    }
 

So how do stop it dropping into negatives, and send the player that they don't have enough coins yadadadada

 

This will return false if the player dont have enough money to remove X amount from, and true otherwise.

Code:

public boolean minusCoins(String player, int amount) {
  int has = coins.get(player);
  if((has - amount) < 0) return false;
  coins.put(player, has - amount);
  return true;
}