private List<Component> getNecessaryComponents(List<SequenceAlternative> sequenceAlternatives) {
		List<Component> necessaryComponents = new LinkedList<>();
		for (SequenceAlternative sa : sequenceAlternatives)
			for (Component component : sa.getComponents())
				if (!necessaryComponents.contains(component))
					necessaryComponents.add(component);
		return necessaryComponents;
	}