Config Injection

[Emily-Jiang]

For config injection, the dependency will be on JSR 330.

Propose :

• Support a singlar property injection for single property lookup e.g. @Inject @ConfigProperty("name") String/other type
• Support a type injection e.g. @Inject @ConfigProperty("prefix") MyConfigMapping mapping;

The property lookup will be identical for single property or ConfigMapping. For ConfigMapping, the value will be treated as prefix while for non configmapping, the name will be the exact property name.

Any thoughts on this?

[dmlloyd]

I would vote "no" on single property injection.

For type injection of configuration mapped objects, I would suggest only supporting the simple form for MVP: @Inject MyConfigMapping mapping;.

[m0mus]

I agree with David. Prefix can be specified as an optional parameter of the annotation placed on the interface.

[dmlloyd]

Here is an example:

public interface MyConfigMapping {
    String name();
    int age();
}

@ConfigMapping // ← this is only (?) strictly necessary when injecting so maybe it should be part of that instead; maybe call it `@InjectableConfig` or something...
public interface OuterMapping {
    MyConfigMapping customer();
    MyConfigMapping client();
}

public class MyBean {
    @Inject OuterMapping theMapping;

    // …
}

[Emily-Jiang]

David and I discussed this during today's call and agreed. In the MVP, the prefix will not be configured. In this case, the annotation ConfigMapping is not required as only one bean is available.

[Emily-Jiang]

I will create a PR with a few sentences for further discussion.

[radcortez]

The injection point should not require (or override the prefix). I believe that was a mistake we made in MP Config. It is a pain to maintain and implement, and it hardly has any usage.

But we still need a way to set up the initial path segment to start the mapping process.