Library Puzzlers - Java Puzzlers: Traps, Pitfalls, and Corner Cases - page 189

Comparator<Integer> cmp = new Comparator<Integer>() {
public int compare(Integer i1, Integer i2) {
return i2 - i1;
}
};
Arrays.sort(arr, cmp);
System.out.println(order(arr));
}
enum Order { ASCENDING, DESCENDING, CONSTANT, UNORDERED };
static Order order(Integer[] a) {
boolean ascending = false;
boolean descending = false;
for (int i = 1; i < a.length; i++) {
ascending |= (a[i] > a[i-1]);
descending |= (a[i] < a[i-1]);
}
if (ascending && !descending)
return Order.ASCENDING;
if (descending && !ascending)
return Order.DESCENDING;
if (!ascending)
return Order.CONSTANT; // All elements equal
return Order.UNORDERED; // Array is not sorted