Reading a NUMERIC from an Avro GENERIC RECORD

ReadNumeric.java

GenericRecord record = input.getRecord()
Schema fieldSchema = record.getSchema().getField(fieldName).schema();
Schema.Type type = fieldSchema.getType();
// LogicalType will be Decimal for NUMERIC, and null for most of other types
Optional<LogicalType> logicalType = Optional.ofNullable(fieldSchema.getLogicalType);
 
switch (type) {
  case BYTES:
    if (!logicalType.isPresent()) {
      // Type is not NUMERIC, Bytes can also be used for the BigQuery BYTES type)
      throw new RuntimeException("We are implementing only NUMERIC parsing")
    }

    // Type is NUMERIC
    // Get scale property
    Decimal decimalType = (Decimal) logicalType.get();
    int scale = decimalType.getScale();
    // Transform value into BigDecimal
    ByteBuffer value = (ByteBuffer) rec.get(fieldName);
    byte[] bytes = new byte[value.remaining()];
    value.get(bytes);
    BigDecimal bigDecimalValue = new BigDecimal(new BigInteger(bytes), scale);
    return bigDecimalValue;
}