/**
  * Check relationList and classRelations both have the same relationships Eventually, relationList
  * must keep synchronous to classRelations Using two nested loop
  */
 public void refreshRelationList() {
   if (classRelations == null || classRelations.size() == 0) {
     return;
   }
   if (relationList == null || relationList.getRelations() == null) {
     this.setRelationList(new RelationList(className, classRelations));
   } else {
     for (ClassRelation classRelation : classRelations) {
       for (ClassRelation iterateRelation : relationList.getRelations()) {
         if (!classRelation.valueEquals(iterateRelation)) {
           relationList.getRelations().add(classRelation);
         }
       }
     }
   }
 }