binding configuration to Names in guice recursively - configuration

Question

My application has configurations which are loaded using parsing annotations into a file using Jackson's fasterxml annotations. For example:
public class RootConfiguration extends Configuration {
#JsonProperty
#NotEmpty
public String foo;
#JsonProperty
public BarConfiguration bar;
public class BarConfiguration extends Configuration {
#JsonProperty
public String baz;
}
}
The configuration is then injected into providers in my Module that help me bind those properties to places in the code that use them. Like so:
#Provides
#Named("config")
public RootConfiguration provideRootConfiguration(RootConfiguration configuration) {
return configuration;
}
#Provides
#Named("config.foo")
public String provideFooConfiguration(RootConfiguration configuration) {
return configuration.foo;
}
#Provides
#Named("config.bar")
public BarConfiguration provideBarConfiguration(RootConfiguration configuration) {
return configuration.bar;
}
And so on.
I'm looking for a framework to help me avoid this tedious work.
I would imagine something that looks like this:
#Configuration(value = "config", bindSubProperties = true)
public class RootConfiguration extends Configuration {
...
That would use Reflection to bind any sub fields in my class as guice Names.
I've looked into Governator's annotations for configurations but as far as I can see they need to be applied to every configuration that I want to bind, which saves me some coding, but is essentially the same (I still have to manually specify the path for each and every configuration I want to bind).
Before I roll out my own implementation for this, is there something that will give me what I need?
Note: I'm using this for a Dropwizard project so the constraint on using Jackson to map the configuration to POJOs is rather tight (unless I move the application configuration outside of the config yaml).

Answer 1

I don't know of any tool that would do this for you, but you could do it yourself pretty easily with something like this:
void bindConfiguration() {
for (Field field : RootConfiguration.class.getFields() {
bindConfiguration(TypeLiteral.get(field.getGenericType()), field);
}
}
<T> void bindConfiguration(TypeLiteral<T> type, Field field) {
bind(type)
.annotatedWith(Names.named("config." + field.getName()))
.toProvider(new ConfigurationProvider<T>(field))
.in(Singleton.class);
}
class ConfigurationProvider<T> implements Provider<T> {
private final Field field;
#Inject RootConfiguration configuration;
ConfigurationProvider(Field field) {
this.field = field;
}
#Override
public T get() {
return (T) field.get(configuration);
}
}