JsonIdentityInfo for Map (not pojo)

[zengkid]

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Describe the bug

I know that @JsonIdentityInfo can resolve the recyle reference for pojo, but how about the Map object?

Version Information

No response

Reproduction

<-- Any of the following

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// sample for map
Map category = new HashMap();
category.put("id", 1);
category.put("name", "category1");

Map product = new HashMap();
product.put("id", 1);
product.put("name", "product1");
product.put("price", "100");
product.put("category", category);

List<Map> products = new ArrayList<>();
products.add(product);
category.put("products", products);

//

Expected behavior

No response

Additional context

No response

[JooHyukKim]

What about it? Could u clarify the intention of this issue?

Seems like Bug Report has been filed. Did identity-info feature ever worked with Maps?

[zengkid]

I'de like to serialize an immutable Map, however, the Map has cyclical references (e.g. map of maps of maps). I can't use any of the POJO annotations (backrefs, Ignore, etc.) as its a dynamic model. I just want to specify the max depth to traverse down the map tree (graph).

Anyone know the easiest way to control the depth of the serializer in either configuration, or perhaps how to override the recursive traversal method in jackson?

[pjfanning]

Jackson has StreamReadConstraints and one applies a default limit to how deep the Jackson parser will traverse. Nesting Depth is the constraint name.

[cowtowncoder]

Easiest thing would be to use a wrapper, to be honest: POJO that contains Map, with @JsonIdentityInfo.

Otherwise in theory you could use mix-in annotations to associate with specific Map type but I am not confident it would work correctly.

This may be one of rare cases where I'd suggest considering custom (de)serializers.

[cowtowncoder]

On constraints: for reading (deserialization), we have StreamReadConstraints; for writing (serialization), StreamWriteConstraints. Both allow limiting maximum nesting depth -- on exceeding, exception is thrown which may or may not be what you want.