Table of Contents

Class NullableFractionJsonConverter

Namespace
DatabentoDotNet.Reference.Json
Assembly
DatabentoDotNet.Reference.dll

Reads and writes a Fraction whose wire code may be blank, mapping the blank to null.

public sealed class NullableFractionJsonConverter : JsonConverter<Fraction?>
Inheritance
NullableFractionJsonConverter
Inherited Members

Remarks

Fraction and PaymentType are the only two of the nine char-coded reference enums with a second converter, and the dictionary is why. The FRACCD and FRACTIONS groups of corporate_actions.list_enums each carry an entry with a null code and the description "A Blank value is possible"; the other six groups do not. Upstream agrees by declaring the field Option<Fraction> (corporate.rs:373). So a blank is a value here rather than a malformed response, and it maps to null.

The empty string is the case that needs this converter; JSON null is not. System.Text.Json answers a null token for a Nullable<T> itself, without reaching the underlying converter — so a Fraction? field carrying only FractionJsonConverter would already read null as no value, and would then throw on "", which is the same absence spelled differently. Verified against System.Text.Json rather than assumed.

HandleNull is true, and it is stated rather than required. System.Text.Json derives the property from whether default(T) is null, so it comes out false here — a Nullable<T> converter is not handed the null token by default, and the framework answers null for it. That is the same answer this converter gives, so the shipped behaviour is identical with the override and without it; probed rather than reasoned about, and note that the nine non-nullable converters get the opposite default for the same rule. It is written down anyway because reading a blank as no value is this file's decision rather than the framework's, and it should stay this file's decision if that default ever moves.

This one has to be named on the property, not on the type. A [JsonConverter] attribute on Fraction can only name one converter, and that is the non-nullable FractionJsonConverter. The model field this exists for is Fraction, declared Fraction? with [JsonConverter(typeof(NullableFractionJsonConverter))] on the property. The source generator does honour a property-level attribute, so registering this converter in Internal/CorporateActionsJson.cs's options as well would be duplication rather than belt-and-braces — established by a test in which a "" reads as null, which is the assertion that would fail if FractionJsonConverter were reached instead.

Properties

HandleNull

true, so a JSON null is a value this converter answers rather than one System.Text.Json answers on its own. Both give null; see the type's remarks for why the override is kept regardless.

public override bool HandleNull { get; }

Property Value

bool

Methods

Read(ref Utf8JsonReader, Type, JsonSerializerOptions)

Reads and converts the JSON to type Fraction?.

public override Fraction? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)

Parameters

reader Utf8JsonReader

The reader.

typeToConvert Type

The type to convert.

options JsonSerializerOptions

An object that specifies serialization options to use.

Returns

Fraction?

The converted value.

Write(Utf8JsonWriter, Fraction?, JsonSerializerOptions)

Writes a specified value as JSON.

public override void Write(Utf8JsonWriter writer, Fraction? value, JsonSerializerOptions options)

Parameters

writer Utf8JsonWriter

The writer to write to.

value Fraction?

The value to convert to JSON.

options JsonSerializerOptions

An object that specifies serialization options to use.

Edit this page