code: private boolean wasResolved(File schemaSourceFile)
    {
      final FileDataSchemaLocation schemaLocation = new FileDataSchemaLocation(schemaSourceFile);
      return _schemaResolver.locationResolved(schemaLocation);
    }
docs: Whether a source file has already been resolved to data schemas.
  
  @param schemaSourceFile provides the source file.
  
  @return true if this source file has already been resolved to data schemas.