presto-main/src/main/java/io/prestosql/spi/expression/ConnectorExpressionTranslator.java/ConnectorToSqlExpressionTranslator/ConnectorToSqlExpressionTranslator
class ConnectorToSqlExpressionTranslator:        public ConnectorToSqlExpressionTranslator(Map<String, Symbol> variableMappings, LiteralEncoder literalEncoder)
        {
            this.variableMappings = requireNonNull(variableMappings, "variableMappings is null");
            this.literalEncoder = requireNonNull(literalEncoder, "literalEncoder is null");
        }