java - Java 泛型的乐趣

Question

有人知道如何使用泛型编写下面的代码片段并避免编译器警告吗？ (@SuppressWarnings("unchecked") 被认为作弊)。

也许，通过泛型检查“左”的类型是否与“右”的类型相同？

public void assertLessOrEqual(Comparable left, Comparable right) {
    if (left == null || right == null || (left.compareTo(right) > 0)) {
        String msg = "["+left+"] is not less than ["+right+"]";
        throw new RuntimeException("assertLessOrEqual: " + msg);
    }
}

Answer 1

这也适用于 Comparable 类型的子类:

public <T extends Comparable<? super T>> void assertLessOrEqual(T left, T right) {
  if (left == null || right == null || left.compareTo(right) > 0) {
    String msg = "["+left+"] is not less than ["+right+"]";
    throw new RuntimeException("assertLessOrEqual: " + msg);
  }
}