迭代变量java

Question

我以随机的方式递增每个变量，直到要分配的点数之和等于0。有没有什么聪明的方法可以减少generate()方法中的代码量，例如，通过迭代变量而不是逐个列出它们？

public class RandomStatsGenerator {

    int Strength = 3;
    int Dexterity = 3;
    int Constitution = 3;
    int Intelligence = 3;
    int Wisdom = 3;
    int Charisma = 3;
    int sum = 45;
    static final int MAX_VALUE = 18;

    public void generate() {
        while (sum> 0 && Strength <= MAX_VALUE) {
            boolean test = getRandomBoolean();
            if (test == true) {
                Strength++;
                sum--;
            }
            test = getRandomBoolean();
            if (test == true && Dexterity <= MAX_VALUE) {
                Dexterity++;
                sum--;
            }
            test = getRandomBoolean();
            if (test == true && Constitution <= MAX_VALUE) {
                Constitution++;
                sum--;
            }
            test = getRandomBoolean();
            if (test == true && Intelligence <= MAX_VALUE) {
                Intelligence++;
                sum--;
            }
            test = getRandomBoolean();
            if (test == true && Wisdom <= MAX_VALUE) {
                Wisdom++;
                sum--;
            }
            test = getRandomBoolean();
            if (test == true && Charisma <= MAX_VALUE) {
                Charisma++;
                sum--;
            }
        }
        System.out.println("Strength: " + Strength + ".");
        System.out.println("Dexterity: " + Dexterity + ".");
        System.out.println("Constitution: " + Constitution + ".");
        System.out.println("Intelligence: " + Intelligence + ".");
        System.out.println("Wisdom: " + Wisdom + ".");
        System.out.println("Charisma: " + Charisma + ".");
    }

    private boolean getRandomBoolean() {
        Random random = new Random();
        return random.nextBoolean();
    }
}

Answer 1

通过提取与参数化方法类似的代码，可以减少类似的代码重复。

为了能够做到这一点，我们需要对你的代码进行一点转换，将相似的代码转换成相同的代码

public void generate() {
    while (sum> 0 && Strength <= MAX_VALUE) {
        int property = Strength;
        boolean test = getRandomBoolean();            
        if (test == true && property <= MAX_VALUE) { // added second condition to catch up with the following ifs
            property++;
            sum--;
        }
        Strength = property;

        property = Dexterity;
        test = getRandomBoolean();
        if (test == true && property <= MAX_VALUE) {
            property++;
            sum--;
        }
        Dexterity = property;
        // same for the rest

现在你有5行完全重复的代码：

        test = getRandomBoolean();
        if (test == true && property <= MAX_VALUE) {
            property++;
            sum--;
        }

您可以选择这5行中的第一行，并应用您的IDE提取方法重构。IDE将替换所选行的所有匹配项。

public void generate() {
    while (sum> 0 && Strength <= MAX_VALUE) {
        int property = Strength;
        property=extracted(property);
        Strength = property;

        property = Dexterity;
        property=extracted(property);
        Dexterity = property;
        // same for the rest
}
private int extracted(int property){
        test = getRandomBoolean();
        if (test == true && property <= MAX_VALUE) {
            property++;
            sum--;
        }
        return property;
}

当然，您应该在extaction过程中给新方法起一个更好的名字。我只是故意保留IDE建议的名称。

最后，您可以在原始方法中内联变量：

  public void generate() {
        while (sum> 0 && Strength <= MAX_VALUE) {
            Strength = extracted(Strength);
            Dexterity = extracted(Dexterity);
            // same for the rest
    }

Answer 2

为您的属性创建枚举，

public enum Attribute {
  STRENGTH,
  DEXTERITY,
  CONSTITUTION,
  INTELLIGENCE,
  WISDOM,
  CHARISMA;
}

然后，创建属性到其值的映射：

Map<Attribute, Integer> attributeValues = new HashMap<>();
attributeValues.put(Attribute.STRENGTH, 3);
attributeValues.put(Attribute.DEXTERITY, 3);
// ...
attributeValues.put(Attribute.CHARISMA, 3);

从贴图中选取一个随机属性并增加它：

Random rand = new Random();
Attribute toIncrement = Attribute.values()[rand.nextInt(Attributes.values().length)];
attributeValues.compute(toIncrement, (k, v) -> v + 1);

把它放在一个循环中，添加跟踪总和的代码，你就应该完成了。

顺便说一句，我不会遍历每次迭代的所有属性，如果你想增加它，就用随机布尔值检查每个属性，因为这将有利于增加的第一个属性。

Answer 3

您可以使用映射并迭代while循环中的条目集：

private Map<String, Integer> map = new HashMap<>();
{
    map.put("Strength", 3);
    map.put("Dexterity", 3);
    map.put("Constitution", 3);
    map.put("Intelligence", 3);
    map.put("Wisdom", 3);
    map.put("Charisma", 3);
}

int sum = 45;

public void generate() {
    while (sum > 0 && map.get("Strength") <= MAX_VALUE) {

        map.entrySet().forEach(entry -> {
            boolean test = getRandomBoolean();
            if (test) {
                map.merge(entry.getKey(), 1, (a, b) -> a + b);
                sum--;
            }
        });
    }

    map.entrySet().forEach(entry -> System.out.println(entry.getKey() + ": " 
       + entry.getValue() + "."));
}

如果所有变量的默认值都是3，您甚至可以使用列表进一步简化它：

List<String> keys = Arrays.asList("Stength", "Dexterity", 
        "Constitution", "Intelligence", "Wisdom", "Charisma");
private Map<String, Integer> map = new HashMap<>();

int sum = 45;

public void generate() {
    do {
        map.entrySet().forEach(entry -> {
            boolean test = getRandomBoolean();
            if (test) {
                map.merge(entry.getKey(), 3, (a, b) -> a + b);
                sum--;
            }
        });
    } while (sum > 0 && map.get("Strength") <= MAX_VALUE);

    //...rest