converter

In the DeleteCommand example, the path parameter is required, while verbosity is optional. The @Parameter and @Option annotations do not have boolean attributes like required or optional. Instead, the multiplicity is determined by the parameter type.

Multiplicity table

(option|param) type	Multiplicity	Arity (if option)
boolean	0..1 (optional)	nullary(*)
Optional<A>	0..1 (optional)	unary
Optional{Int,Long,Double}	0..1 (optional)	unary
List<A>	0..* (repeatable)	unary
A (exact match)	1 (required)	unary

where A must be one of the auto types, otherwise compilation will fail.

(*) only available when the converter Attribute is not set