code: public boolean canBeInObjStm() {
          switch (type) {
              case NULL:
              case BOOLEAN:
              case NUMBER:
              case STRING:
              case NAME:
              case ARRAY:
              case DICTIONARY:
                  return true;
              case STREAM:
              case INDIRECT:
              default:
                  return false;
          }
      }
docs: Whether this object can be contained in an object stream.
  
  PdfObjects of type STREAM OR INDIRECT can not be contained in an
  object stream.
  
  @return <CODE>true</CODE> if this object can be in an object stream.
  Otherwise <CODE>false</CODE>