Representing optional beams in the note class

BaseNoteModel.java

public class BaseNoteModel extends StaffElementModel {
	
	// snip ...
	
	/*
	 * A note or rest can have multiple beams
	 */
	private Optional<List<BeamEnum>> beams = Optional.empty();
	
	// snip ... 
	
	public Optional<List<BeamEnum>> getBeams() {
		return beams;
	}
	public void setBeams(Optional<List<BeamEnum>> beams) {
		this.beams = beams;
	}	

}