apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/service/ItemService.java/ItemService/isModified
class ItemService:  private boolean isModified(String sourceValue, String targetValue, String sourceComment, String targetComment) {

    if (!sourceValue.equals(targetValue)) {
      return true;
    }

    if (sourceComment == null) {
      return !StringUtils.isEmpty(targetComment);
    }
    if (targetComment != null) {
      return !sourceComment.equals(targetComment);
    }
    return false;
  }