Generating Annotations, Lombok Lite for ConfigLib

[RE4ERKA]

The Lombok library, which generates methods and constructors using annotations, indeed works very well with ConfigLib library. However, configuration classes often become too verbose due to the number of annotations, especially when there are many configuration sections (i.e., nested classes).

It would be great if, despite the fact that this functionality can already be fully achieved through Lombok, using just a single @Configuration annotation could automatically generate getters and, more importantly, empty constructors required for reflective instantiation of the class.

Example class using Lombok:

@Getter
@Accessors(fluent = true)
@NoArgsConstructor(access = AccessLevel.PRIVATE)
@SuppressWarnings("FieldMayBeFinal")
@Configuration
public final class BaseConfiguration {

  private String content;
  private int value;

  private ConfigurationSection = new ConfigurationSection();

  @Getter
  @Accessors(fluent = true)
  @NoArgsConstructor(access = AccessLevel.PRIVATE)
  @Configuration
  public final class ConfigurationSection {
    
    private String content;
    private int value;
  }
}

A more concise version:

@SuppressWarnings("FieldMayBeFinal")
@Configuration(fluent = true)
public final class BaseConfiguration {

  private String content;
  private int value;

  private ConfigurationSection = new ConfigurationSection();

  @Configuration(fluent = true)
  public final class ConfigurationSection {
    
    private String content;
    private int value;
  }
}

In my example, the @Configuration annotation also takes into account whether the getters should be fluent or not, which is useful for those who prefer even more concise methods for accessing values from the class.

Most likely, a separate project would need to be created for these annotations — something like ConfigLib-Annotations — which users would also need to add to their project dependencies if they want to use these annotations.

implementation 'de.exlll:configlib-yaml:4.6.1'

compileOnly 'de.exlll:configlib-annotations:1.0.0'
annotationProcessor 'de.exlll:configlib-annotations:1.0.0'

[Exlll]

Hey @RE4ERKA, this is an interesting proposal, thank you!

I suppose that introducing such functionality would also require support from IDEs as without such support IDEs will not be aware of the auto-generated methods and will therefore be complaining when someone tries to call them in other parts of their code, right?

Perhaps you can use Java records instead of classes? If you define ConfigurationSection as a record, you not only get the getters you're interested in but you also don't have to annotate the record definition with @Configuration.

[RE4ERKA]

Hey @RE4ERKA, this is an interesting proposal, thank you!

I suppose that introducing such functionality would also require support from IDEs as without such support IDEs will not be aware of the auto-generated methods and will therefore be complaining when someone tries to call them in other parts of their code, right?

Perhaps you can use Java records instead of classes? If you define ConfigurationSection as a record, you not only get the getters you're interested in but you also don't have to annotate the record definition with @Configuration.

Yes, you're right. In my specific example, using a Java record would make sense.

But in practice (or almost always, from what I've seen), I prefer to initialize the fields of my configuration classes directly where they are declared.

About IDE support, yeah, that could complicate things. Still, if you ever decide to implement something like this, like I said earlier, it'd be cool, even if it's not a must-have.

[Exlll]

Yes, I agree that it would be cool. But I don't think that it makes sense to spend time implementing functionality that Lombok (and the tooling around it) already provides - at least not as long as I have other features to work on.

I prefer to initialize the fields of my configuration classes directly where they are declared.

You could do something similar with records by initializing the values in zero-args constructor:

public record ConfigurationSection(String content, int value) {
    public ConfigurationSection() {
        this("Initial value", 10);
    }
}

This has the added benefit that the compiler will complain if you forget to provide a default value for a component.