docs: public BundleLinkComponent getLinkOrCreate(String theRelation) {
      org.apache.commons.lang3.Validate.notBlank(theRelation, "theRelation may not be null or empty");
      for (BundleLinkComponent next : getLink()) {
        if (theRelation.equals(next.getRelation())) {
          return next;
        }
      }
      BundleLinkComponent retVal = new BundleLinkComponent();
      retVal.setRelation(theRelation);
      getLink().add(retVal);
      return retVal;
    }