code: public boolean joinLine() {
  		if (!isCurrentLine()) {
  			return false;
  		}
  		if (!isNextLine()) {
  			return false;
  		}
  		if (!isNextTag()) {
  			return true; // no next tag -> continue block
  		}
  		if (!isCurrentTag()) {
  			return false; // no current tag -> new block
  		}
  		// compare current and next tag
  		return getCurrentTag().equals(getNextTag());
  	}
docs: Returns true if the next and current lines can be joined together either
  because they have the same tag or because the next line does not have a
  tag.