java - 如何编写比较器以将列表的所有元素与输入进行比较并移动到顶部

Question

我有一个列表

List<String> myList = Arrays.asList("1234", "1214", "1334");

我的输入是:

String mInput = "1214"

---

如何编写一个比较器，将myList的所有元素与mInput进行比较，如果相等，则将其移至列表顶部

Answer 1

您可以编写自己的比较器:

class BringToFrontComparator<T extends Comparable<T>> implements Comparator<T> {
    T front;

    public BringToFrontComparator(T front) {
        this.front = front;
    }

    @Override
    public int compare(T o1, T o2) {
        return o1.equals(front) && !o2.equals(front)
                // Front one is always less than anything other than itself.
                ? -1
                // Normal comparison elsewhere.
                : o1.compareTo(o2);
    }
}

public void test(String[] args) throws Exception {
    List<String> myList = Arrays.asList("1234", "1214", "1334");
    String mInput = "1334";
    Collections.sort(myList, new BringToFrontComparator<>(mInput));
    System.out.println(myList);
}

打印

[1334, 1214, 1234]