public String resolveAttributeType(ObjectProperty attribute) {
   StringBuffer type = new StringBuffer("");
   if (attribute.isMultiple()) {
     if (attribute.getBag() != null && !"".equals(attribute.getBag())) {
       type.append(attribute.getBag());
     } else {
       type.append("java.util.List");
     }
     type.append("<");
   }
   type.append(attribute.getClassName());
   if (attribute.isMultiple()) {
     type.append(">");
   }
   return type.toString();
 }