Follow up of Unknown Enum Deserialization issues , Map : <Enum,String>

[isuribb]

Hi

This is a follow up issue from "issue handling unknown/unmapped Enum keys #1859"

Tried using the "READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE " with the JsonEnumDefaultValue annotation. It worked for the type Enum as expected. Then we have another issue where we are using a Map<Enum,String> object in our Bean class which didnot get resolved with above. When tried debugging, noticed the following code is going inside the class, EnumResolver since we a . It would be good if we can handle the same default value handling done in EnumDeserializer class , on this class as well so that we can use the default value we have defined. Appreciate a quick response.. Thank you.

StdKeyDeserializer :

@Override
public Object _parse(String key, DeserializationContext ctxt) throws IOException
{
if (_factory != null) {
try {
return _factory.call1(key);
} catch (Exception e) {
ClassUtil.unwrapAndThrowAsIAE(e);
}
}
EnumResolver res = ctxt.isEnabled(DeserializationFeature.READ_ENUMS_USING_TO_STRING)
? _getToStringResolver(ctxt) : _byNameResolver;
Enum<?> e = res.findEnum(key);
if ((e == null) && !ctxt.getConfig().isEnabled(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_AS_NULL)) {
return ctxt.handleWeirdKey(_keyClass, key, "not one of values excepted for Enum class: %s",
res.getEnumIds());
// fall-through if problems are collected, not immediately thrown
}
return e;
}

[cowtowncoder]

As per my comments on the issue, you do need to change type to EnumMap. Handling for regular Map with Enum key will not fully work.

[isuribb]

We are unable to use EnumMap since the beans are generated through Apache Thrift, which is only allowing Map "HashMap".

[cowtowncoder]

@isuribb then you will probably need a custom key deserializer (or deserializer).

[mawifu]

It seems like EnumDeserializer works different than StdKeyDeserializer.EnumKD for Enums as keys.
#1877 is another issue which shows another facet of this unbalance.
There EnumMap doesn't solve the problem.

[isuribb]

Thanks All... We went with a custom deserilizer and defaulting to a custom value and it resolved our issue. EnumMap also was not an option due to thrift model is not supporting any custom maps except map and tree map.

[cowtowncoder]

@mawifu true, ordinals are not (for now) supported for keys. But for this issue I EnumMap does matter, wrt filtering (exclusion).

I also do think that for Jackson 3.0 I can do something that helps here, that I realized now: it should be possible to map all Map<ENUMTYPE,V> types into EnumMap<ENUMTYPE,v>, as "abstract type mapping" -- Map otherwise maps to LinkedHashMap by default (since it must map to a concrete type). So if key type is of Enum type, such mapping would make sense.
That would not only help with some of enum-specific handling, but also make things more efficient, and users can still use more specific type (like TreeMap or HashMap) if they really want some other type.

I will file another issue for that work. Thank you for all the input here.