| Interface | Description | 
|---|---|
| DependentSourceSet | A source set that can have dependencies on other Libraries. | 
| FunctionalSourceSet | A container holding  LanguageSourceSets with a similar function
 (production code, test code, etc.). | 
| LanguageSourceSet | A set of sources for a programming language. | 
| ProjectSourceSet | A container of  LanguageSourceSets. |