Class: Avromatic::IO::DatumWriter

Inherits:
Avro::IO::DatumWriter
  • Object
show all
Defined in:
lib/avromatic/io/datum_writer.rb

Overview

Subclass DatumWriter to use additional information about union member index.

Instance Method Summary collapse

Instance Method Details

#write_union(writers_schema, datum, encoder) ⇒ Object

Raises:

  • (Avro::IO::AvroTypeError) 


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# File 'lib/avromatic/io/datum_writer.rb', line 8

def write_union(writers_schema, datum, encoder)
  optional = writers_schema.schemas.first.type_sym == :null
  if datum.is_a?(Avromatic::IO::UnionDatum)
    index_of_schema = datum.member_index
    # Avromatic does not treat the null of an optional field as part of the union
    index_of_schema += 1 if optional
    datum = datum.datum
  elsif optional && writers_schema.schemas.size == 2
    # Optimize for the common case of a union that's just an optional field
    index_of_schema = datum.nil? ? 0 : 1
  else
    index_of_schema = writers_schema.schemas.find_index do |schema|
      Avro::Schema.validate(schema, datum)
    end
  end

  raise Avro::IO::AvroTypeError.new(writers_schema, datum) unless index_of_schema

  encoder.write_long(index_of_schema)
  write_data(writers_schema.schemas[index_of_schema], datum, encoder)
end