compareTo method
Compares this object to another object.
Returns a value like a Comparator when comparing this
to other
.
That is, it returns a negative integer if this
is ordered before other
,
a positive integer if this
is ordered after other
,
and zero if this
and other
are ordered together.
The other
argument must be a value that is comparable to this object.
Implementation
int compareTo(other) {
if (other == null) return 1;
if (other is AbstractKey) {
if (key == null && other.key == null) return 0;
return key!.compareTo(other.key);
}
return -1;
}