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Refactoring of format-specific read/write features for Jackson 3

Author

Tatu Saloranta (@cowtowncoder)

Version history

• 2024-11-20: first and definitive version

Status

Work completed on 2024-11-20.

Overview

As of Jackson 2.x, format-specific features have been typically added as inner-class Enums of format-specific parsers/generators: for example, Avro module (jackson-dataformat-avro) has:

• AvroParser.Feature for reader-side on/off features
• AvroGenerator.Feature for writer-side on/off features

Not all formats have such features (and some only reader- or writer-side ones), but all follow the same pattern. This was modeled based on original JsonParser.Feature (mix of JSON-specific and general features), JsonGenerator.Feature approach. Jackson 2.10, however, split JsonParser.Feature into 2 sets of Features:

• StreamReadFeature for general-purpose (cross-format, non-JSON-specific) features
• JsonReadFeature for JSON-specific features

While there is no confusion on format-specific/general features outside of JSON package, it seems ideal to follow same naming convention, so that:

• AvroParser.Feature becomes AvroReadFeature
• AvroGenerator.Feature becomes AvroWriteFeature

Changes by component

Here are issues created for work on this JSTEP, by format module:

• Avro: dataformats-binary#522
• CBOR: dataformats-binary#524
• CSV: dataformats-text#510
• Ion: dataformats-binary#526
• Properties: No read/write features, nothing to do
• Protobuf: No read/write features, nothing to do
• Smile: dataformats-binary#528
• TOML: Already using "new style" read/write features, nothing to do
• XML: dataformat-xml#687
• YAML: dataformats-text#512