code: public void format(StringBuilder sb, Object value) {
  		if (prefix != null) {
  			sb.append(prefix);
  		}
  		if (percentExpression != null && value != null) {
  			percentExpression.append(value, sb);
  		}
  		if (suffix != null) {
  			sb.append(suffix);
  		}
  	}
docs: Formats the extracted value assigned and returns the associated string