code: private int getTagIndex(final String tag) {
  		if (tag == null) {
  			return 0;
  		} else {
  			int index = knownTags.indexOf(tag);
  			return index == -1 ? knownTags.size() + 1 : index + 1;
  		}
  	}
docs: Gets the index of a tag.
  
  @param tag
  Name of tag
  @return Index of tag