Problem with Stack

Question

Hi,
I need a stack implementation of an stack. I found some code on http://download-west.oracle.com/docs/cd/B10501_01/appdev.920/a96624/10_objs.htm (see chapter Object Type Example: Stack), but I don't know how to handle it.
When I try
declare
  s Stack;
begin
  s.INITIALIZE;
end;I get an ORA-30625
ORA-30625: Methoden-Dispatch mit Argument NULL SELF ist nicht zulässig
ORA-06512: in Zeile 4can somebody please help me and show me where's the problem or how I have to handle this object?
Thanks

Answer 1

can somebody please help me and show me where's the problem or how I have to handle this object?
SQL>  create type intarray as varray (25) of integer;
Type created.
SQL>  create type stack as object (
   max_size   integer,
   top        integer,
   position   intarray,
   member procedure initialize
Type created.
SQL>  create type body stack
as
   member procedure initialize
   is
   begin
      top := 0;
      /* call constructor for varray and set element 1 to null. */
      position := intarray (null);
      max_size := position.limit;               -- get varray size constraint
      position.extend (max_size - 1, 1);         -- copy element 1 into 2..25
   end initialize;
end;
Type body created.
SQL>  declare
   s   stack := stack (null,null,null);
begin
   s.initialize;
end;
PL/SQL procedure successfully completed.