code: @Override
    public Set<String> getProperties() {
  		Set<String> result = new HashSet<String>();
  		for (DefinedUnit unit : model.getDefinedUnits()) {
  			result.add(unit.getProperty());
  		}
  		return result;		
  	}
docs: /* (non-Javadoc)
  @see org.eclipse.ohf.ucum.UcumServiceEx#getProperties()