检查具有特定值的类是否在hashmap的键中？

Question

我有一个班级：

public class Decision {
    int leftIndex;
    int rightIndex;
    String player;
    public Decision(int leftIndex, int rightIndex, int player) {
        this.leftIndex = leftIndex;
        this.rightIndex = rightIndex;
        this.player = player;
    }
}

和实例化散列映射的类（作为缓存，使用Decision值作为键和整数值）并检查特定Decision值是否已保存结果。如果是这样，我们会返回该结果。否则，我们计算该值并将其存储在hashmap中。我怎样才能让它发挥作用？有一个更好的方法吗？我没有想法，这就是我的想法。

public class Game {

    Map<Decision, Integer> hm = new HashMap<Decision, Integer>();
    int checkIfExists(int left, int right, String player) {
        if (hm.containsKey(new Decision(left, right, player)) {
            return hm.get(new Decision(left, right, player));
        } else {
            // compute value of decision
            hm.add(new Decision(left, right, player), result);
        }
        return result;
    }
}