code: protected final SourceFolder getOrCreateSourceFolder(String name) {
  		SourceFolder sourceFolder = this.sourceFolders.get(name);
  		if (sourceFolder == null) {
  			sourceFolder = new SourceFolder(name);
  			this.sourceFolders.put(name, sourceFolder);
  		}
  		return sourceFolder;
  	}
docs: Get or create a {@link SourceFolder} with the given name.
  @param name the name of the folder
  @return an existing or newly added {@link SourceFolder}