/// <summary>
/// Converts the JSON stored in a reader into the relevant Noda Time type.
/// </summary>
/// <param name="reader">The Json.NET reader to read data from.</param>
/// <param name="objectType">The type to convert the JSON to.</param>
/// <param name="existingValue">An existing value; ignored by this converter.</param>
/// <param name="serializer">A serializer to use for any embedded deserialization.</param>
/// <exception cref="InvalidNodaDataException">The JSON was invalid for this converter.</exception>
/// <returns>The deserialized value.</returns>
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null)
{
Preconditions.CheckData(objectType == NullableT,
"Cannot convert null value to {0}",
objectType);
return(null);
}
// Handle empty strings automatically
if (reader.TokenType == JsonToken.String)
{
string value = (string)reader.Value;
if (value == "")
{
Preconditions.CheckData(objectType == NullableT,
"Cannot convert null value to {0}",
objectType);
return(null);
}
}
// Delegate to the concrete subclass. At this point we know that we don't want to return null, so we
// can ask the subclass to return a T, which we will box. That will be valid even if objectType is
// T? because the boxed form of a non-null T? value is just the boxed value itself.
// Note that we don't currently pass existingValue down; we could change this if we ever found a use for it.
return(ReadJsonImpl(reader, serializer));
}
/// <summary>
/// Reads the time zone ID (which must be a string) from the reader, and converts it to a time zone.
/// </summary>
/// <param name="reader">The JSON reader to fetch data from.</param>
/// <param name="serializer">The serializer for embedded serialization.</param>
/// <exception cref="DateTimeZoneNotFoundException">The provider does not support a time zone with the given ID.</exception>
/// <returns>The <see cref="DateTimeZone"/> identified in the JSON, or null.</returns>
protected override DateTimeZone ReadJsonImpl(JsonReader reader, JsonSerializer serializer)
{
Preconditions.CheckData(reader.TokenType == JsonToken.String,
"Unexpected token parsing instant. Expected String, got {0}.",
reader.TokenType);
var timeZoneId = reader.Value.ToString();
return(provider[timeZoneId]);
}