找到所有可能的枚举组合

Question

有没有一种有效的方法来查找Java中多个枚举之间的所有可能组合？

考虑以下三个枚举 -

public enum EnumOne {
   One ("One"),
   OneMore ("OneMore");
}

public enum EnumTwo {
   Two ("Two"),
}

public enum EnumThree {
   Three ("Three"),
   ThreeMore ("ThreeMore");
}

我希望输出产生这些多个枚举之间的所有可能组合,即

{EnumOne.One, EnumTwo.Two, EnumThree.Three},
{EnumOne.One, EnumTwo.Two, EnumThree.ThreeMore},
{EnumOne.OneMore, EnumTwo.Two, EnumThree.Three},
{EnumOne.OneMore, EnumTwo.Two, EnumThree.ThreeMore}

希望找到一种有效的方法来处理它.

谢谢

Answer 1

像这样的事情怎么样？

void printAll(List<Class> enums, int i, String[] msg) {
    if (!enums.get(i).isEnum()) {
        throw new IllegalStateException();
    }
    Object[] enumsConstants = enums.get(i).getEnumConstants();
    if (i == 0) {
        //first iteration
        for (Object o : enumsConstants) {
            if (enums.size() == 1) {
                System.out.println("{ " + o.toString() + " }");
            } else {
                msg = new String[enums.size()];
                msg[0] = "{ " + o.toString();
                printAll(enums, i + 1, msg);
            }
        }
    } else if (i == enums.size() - 1) {
        //on the last iteration
        for (Object o : enumsConstants) {
            msg[i] = ", " + o.toString() + " }";
            System.out.println(Arrays.toString(msg));
        }
    } else {
        //middle iteration
        for (Object o : enumsConstants) {
            msg[i] = ", " + o.toString();
            printAll(enums, i + 1, msg);
        }
    }
}

你会像这样使用它

printAll(allMyEnumClassesList, 0, null);