Control serialization of a Map (order: explicit + alphanumeric)

[lfvjimisola]

It could be that I can solve this like this, but it's seem like overkill.

1. I have a Map data that I want to be in alphanumeric order (D1, D2) etc.

For this I can use mapper.configure(SerializationFeature.ORDER_MAP_ENTRIES_BY_KEYS, true);

2. However, on the same level as data I want additiontal key/value such as version. And I want version to be on top and the rest of the Map shall be in alphanumeric order. I use a Map result with { "version" = "0.0.1", data = { D1 = {..}, D2 = {..} } }.

Is it possible to create deterministic serialization where I can control the order (similar to @JsonPropertyOrder but) for Maps so that it's a combination of explicit and alphanumeric. Ideally, something similar to @JsonPropertyOrder because then I could use:

@JsonKeyOrder ({"version"}, alphabetic = true)
Map result;

@JsonKeyOrder (alphabetic = true)
Map data;

version: "0.0.1"
data:
  D1:
  - element: "dataX"
    category: 1
  D2:
  - element: "dataY"
    category: 1
  - element: "dataZ"
    category: 2

[cowtowncoder]

No, there is no way to do that with default annotations (or AnnotationIntrospector) that I know.
Maps -- unlike POJOs -- are assumed to be mostly unordered collections of things, with less emphasis on output ordering. As such options are limited.

I guess from user perspective support could be added to consider @JsonPropertyOrder, if anyone has time to propose a PR.
If so, might be worth filing an issue asking for/suggesting implementation.

[pjfanning]

What happens if you use a TreeMap? For me, that is the right type to use if you want a map with ordered keys.