docs: public IFeatureAlphabet rebuildFeatureAlphabet(String name)	{
  		IFeatureAlphabet alphabet = null;
  		if (maps.containsKey(name))	{
  			alphabet = (IFeatureAlphabet) maps.get(name);
  			alphabet.clear();
  		}else{
  			return buildFeatureAlphabet(name,defaultFeatureType);
  		}
  		return alphabet;
  	}