code: private Set<String> getInString(List<ModificationFeature> list)
  	{
  		Set<String> text = new HashSet<String>(list.size());
  
  		for (ModificationFeature mf : list)
  		{
  			String term = getModificationTerm(mf);
  			String loc = getPositionInString(mf);
  
  			if (term != null)
  			{
  				String s = term + loc;
  				if (!text.contains(s)) text.add(s);
  			}
  		}
  		return text;
  	}
docs: Gets the modifications is a string that is separated with comma.
  @param list modification list
  @return String representing the modifications