Deserialize a SortedSet with a provided Comparator

Question

Is it possible to deserialise a SortedSet or TreeSet (or SortedMap or TreeMap as a matter of fact) with a provided Comparator?

Answer 1

There is an open Jackson issue (jackson-databind#2162) to allow specifying a Comparator when deserializing a SortedMap. It has been open since October 2018, but it doesn't look like any work has been done on it.

Answer 2

One solution is to create a custom Converter which converts a SortedSet to one which is sorted using the desired Comparator:

public static class MyStringSetConverter
        extends StdConverter<SortedSet<String>, SortedSet<String>> {
    private static final Comparator<String> COMPARATOR =
            String.CASE_INSENSITIVE_ORDER
                    .thenComparing(Comparator.naturalOrder());

    @Override
    public SortedSet<String> convert(SortedSet<String> value) {
        SortedSet<String> sortedSet = new TreeSet<>(COMPARATOR);
        sortedSet.addAll(value);
        return sortedSet;
    }
}

public static class MyType {
    @JsonDeserialize(converter = MyStringSetConverter.class)
    private SortedSet<String> value;

    public SortedSet<String> getValue() { return value; }
    public void setValue(SortedSet<String> value) { this.value = value; }
    public String toString() { return Objects.toString(value); }
}