public Object freeze(ColumnLoader.ValueSet valueSet) {
final int n = valueSet.map.keySet().size();
int extra = valueSet.containsNull ? 1 : 0;
Comparable[] codeValues = valueSet.map.keySet().toArray(new Comparable[n + extra]);
Arrays.sort(codeValues, 0, n);
ColumnLoader.ValueSet codeValueSet = new ColumnLoader.ValueSet(int.class);
for (Comparable value : valueSet.values) {
int code;
if (value == null) {
code = n;
} else {
code = Arrays.binarySearch(codeValues, value);
assert code >= 0 : code + ", " + value;
}
codeValueSet.add(code);
}
Object codes = representation.freeze(codeValueSet);
return Pair.of(codes, codeValues);
}
