JSTEP 7

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New DataTypeFeature configuration options (Jackson 2.x)

Related change issues: JSTEP-3 contains/-ed aspects of JsonNodeFeature

Author

Tatu Saloranta (@cowtowncoder)

Version history

• 2022-01-16: The first draft version

Background

Over time, various XxxFeature on/off options have proven useful and popular with developers: they are easy to set, change and (for the most part), understand.

Original set of "Features" were configurable at Streaming API and Databind level, including:

• JsonParser.Feature / JsonGenerator.Feature / JsonFactory.Feature for Streaming API
• MapperFeature / SerializationFeature / DeserializationFeature for databind

and for Streaming API, further split of format-specific (often JSON-specific) vs. generic (across all or most formats) features, resulted in:

• JsonParser.Feature split into generic StreamReadFeature and XxxReadFeature (like JsonReadFeature)
• JsonGenerator.Feature split into generic StreamWriteFeature and XxxWriteFeature (like JsonWriteFeature).

But while this split allowed better support for Format-specific features (via Streaming API), there is no similar mechanism for more granular configuration for datatype-specific features. This has lead to inclusion of some "too [datatype] specific" features at databind level; for example:

• DeserializationFeature.READ_ENUMS_USING_TO_STRING
• DeserializationFeature.READ_DATE_TIMESTAMPS_AS_NANOSECONDS
• SerializationFeature.WRITE_DATES_AS_TIMESTAMPS

Such configuration is against the idea that these Features should be cross-cutting across dataformats AND datatypes. But it is worth noting that there is need for such configuration, at some other granularity. This lead to the idea of "datatype-specific" features.

Challenges, choices