@Override
 public String toExpression() {
   if (!objType.equals(fieldType)) {
     return "((" + objType + ") " + parentIr.toExpression() + "." + fieldName + ")";
   } else {
     return parentIr.toExpression() + "." + fieldName;
   }
 }
 public GetInvokerRecord(String fieldType, String fieldName, InvokerRecord parentIr) {
   this.parentIr = parentIr;
   this.fieldName = fieldName;
   this.fieldType = fieldType;
   parentIr.incUsageCount();
 }