High level api for route parameters.

Add support for multiple route parameters deserialisation.

It can be similar to HasUrlParameter which supports deserialisation of one route parameter.

Make use of the route parameters api implemented in https://github.com/vaadin/flow/pull/7608.

Related to https://github.com/vaadin/flow/issues/2740 and https://github.com/vaadin/flow/issues/4213

[Legioth]

My hypothesis is that at least 80% of all cases will need only one parameter. Out of the remaining 20%, another 80% will need only two parameters and so on.

The 80% case with only one parameter is already nicely served by the current HasUrlParameter<T> API. My main question is whether any design for he remaining 20% would bring so much improvements to application cod that it would be worth the investment from our side compared to some other DX improvements that we could do that would target some more common use case.

Other cases can with relatively little boilerplate do something like this:

String param1 = parameters.get("foo").orElse(null);
int param2 = parameters.get("bar", -1);

Introducing a DTO for those two parameters would require the additional overhead of actually defining that DTO class. That DTO could then be used in combination with the current one-parameter approach as HasUrlParameter<DtoType>. The actual routing code could then be simplified to this:

String param1 = dto.getFoo();
int param2 = dto.getBar();

The reduction in the needed code is quite minimal, but a secondary benefit is that type conversions and magic strings are moved out of sight. Another benefit is the possibility of creating a RouterLink based on an instance of dto (which would work without additional API additions if done based on HasUrlParameter<DtoType>).

[bogdanudrescu]

Actually, in our routing context there should be no need for handling these exceptions if the route is defined correctly. If the regex assigned to the route parameter doesn’t match the value of the parameter in the url, then the navigation fails before reaching conversion phase.