Instant, YearMonth and MonthDay not use pattern in @JsonFormat

[devdevx]

I'm trying to define a custom patterns for this classes but sems that the @JsonFormat is ignored.

Jackson version: 2.9.3
Jackson datatype version: 2.9.6

Example of @JsonFormat anotation:

    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd/MM/yyyy HH_mm_ss_SSS|z")
    private Instant customInstant;
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy/MM")
    private YearMonth customYearMonth;
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "MM_dd")
    private MonthDay customMonthDay;

Current result:

When serialize the fields are formated with the default pattern and when deserialize a exception is throw.

Expected result:

Serialization and deserialization works sucessfully using the defined pattern.

Thanks !

[cowtowncoder]

Thank you for reporting the problem. I assume reproduction should be easy, if anyone has time to look into this (I may have but right now no guarantees).

[devdevx]

After reading the source code I think that this could work:

• YearMonth serialization

YearMonth uses the ToStringSerializer.instance, it should be replaced by a new class (maybe YearMonthSerializer) that extends the JodaDateSerializerBase and should be similar to LocalDateSerializer.

• YearMonth deserialization

YearMonthDeserializer should extend JodaDateDeserializerBase instead of JodaDeserializerBase.

Doing this the attribute this._formatter should contain the formatter for the custom pattern (or the default pattern if custom not exist?)

In the method deserialize of YearMonthDeserializer we need to change the YearMonth.parse(str) by YearMonth.parse(str, this._formatter)

• MonthDay serialization

MonthDay uses the ToStringSerializer.instance, it should be replaced by a new class (maybe MonthDaySerializer) that extends the JodaDateSerializerBase and should be similar to LocalDateSerializer.

• MonthDay deserialization

MonthDayDeserializer should extend JodaDateDeserializerBase instead of JodaDeserializerBase

Doing this the attribute this._formatter should contain the formatter.

In the method deserialize of MonthDayDeserializer we need to change the MonthDay.parse(str) by MonthDay.parse(str, this._formatter)

• Instant serialization

In InstantSerializer the gen.writeString(value.toString()) of the method serialize should be replaced by gen.writeString(this._format.createFormatter(provider).print(value))

• Instant deserialization

InstantDeserializer should extend JodaDateDeserializerBase instead of JodaDeserializerBase

Doing this the attribute this._formatter should contain the formatter.

In the method deserialize of InstantDeserializer we need to change the new Instant(str) by Instant.parse(str, this._formatter)

What do you think? If you wish, I think that I could try to do a PR in the comming days.

[cowtowncoder]

@devdevx I think that makes sense, and help would be welcome. I'll see if I could implement part of this, maybe InstantDeserializer, as a starting point. Changes can and should go against 2.9 branch since there's no API change; and that way would get in 2.9.7.

[cowtowncoder]

I was able to implement support for custom format for Instant, leaving MonthDay and YearMonth.