Multiple converter for Map

[sbernard31]

I would like to do something like :

@Option(
        names =  { "-mo", "--my-option } ,
        description = { "syntax is : - attrKey1=attrValue1,attrKey2=attrValue2" },
        split = ",")
public Map<Type1, Type2> myOption;

Note there is no default converter for Type1 and Type2.

Ideally :

1. I would like to add converter to this option for both type.
2. I would like to validate that attrValue is a valid value for the given attrKey.

I don't know what is the recommended way ?

From a user perspective, I would like to be able to just add a converter which respect this API :

public interface IMapTypeConverter<K,V> {
  // Maybe there is better idea than Map.entry ?
   Map.entry<K,V> convert(String key, String value) throws Exception;
}

(I share the idea just in case)

I guess solutions with current API could be :

• Register converters to the command (using CommandLine.registerConverter) and do post validation (in run() when using Runnable) ?
• OR use a collection of <Map.entry<K,V> (or a decicated class) with only one converter but I need to split by "=" by myself ?

Any advice or recommendation?

[remkop]

I would use CommandLine.registerConverter to register type converters for the key and value types.

Validation can be done in the run method like you said, or you can have an annotated setter method instead of an annotated Map field. That allows you to do the validation in the setter method. However picocli will call this method multiple times; using the run method is probably simpler.

This section in the user manual has examples for both ways to do validation.

[sbernard31]

Thx for quick answer 🙏

Any opinion about the IMapTypeConverter idea ?

[remkop]

To be honest I am not enthusiastic about adding API for something that can already be accomplished with the existing functionality.

[sbernard31]

I guess there is a lot of feature which are just about making some use case more easier/straightforward to use.

E.g. : CommandLine.registerConverter vs converter = MyConverter.class seems like redundant feature.

But I can understand that you could think that this use case is not common enough to deserve dedicate feature.

Anyway, thx again for your help 🙏

(On my side, I get my answers so, feel free to close the issue)