enum ordinal serialization

[ias-dt]

Enums serialized via it's ordinal value will get sent in JSON notation as an integer. In piriti in the enum.vm template for the reader there is a check if the sent value is a string. So currently we cannot use enum ordinal serialization. Even if we tried to implement a converter it would not kick in, as it is only called after the string check.

We propose an extension to the enum.vm reader template like the following:

• if it's not a string try to get the enum value via it's ordinal value

so something like this (beware, not syntax checked or tried)

if (${jsonValue}.isNull() == null) 
{
    JSONString jsonString = ${jsonValue}.isString();
    if (jsonString != null)
    {
// [..]
    } 
    else 
    {
        $valueType[] values = $valueType.values();
        if (0 <= $jsonValue && $jsonValue < values.length) 
                {
            $value = values[$jsonValue];
        }
    }
}

would ensure the reader works out of the box with enums serialized as name and as ordinal without any need for configuration.

For the writer something similar, but with some new configuration switch.

if ($value != null)
{
    #if ($property.converter)
        #createConverter()
        String $valueAsString = ${converter}.serialize($value);
    #else
        #if ($property.asOrdinal)
            String $valueAsString = $value.ordinal();
        #else
            String $valueAsString = String.valueOf($value);
        #end
    #end
    if (isNumber($valueAsString))
    {
        out.append($valueAsString);
    }
    else
    {
        out.append(JsonUtils.escapeValue($valueAsString));
    }
}
else
{
    out.append("null");
}