Error Handling in WebUtil CLIENT_OLE2.get_obj_property

Question

Hello,
we have a problem with the error handling in WebUtil's CLIENT_OLE2.get_obj_property function. The WebUtil version is 1.0.2 and the problem can be reproduced on the 9iAS, 9iDS and 10gAS as well.
Problem description:
The get_obj_property function does not throw a PL/SQL exception when it is given an invalid object as first argument (i.e. an object handle to an application that has intermittently been closed by the user). Instead, the function returns a NULL value and the control flow of our application code continues as if the function had succeeded. So the problem is that the get_obj_property function neither throws an exception nor can the failure be caught by calling WEBUTIL_CORE.IsError as this returns that no error occurred.
Example:
PACKAGE BODY word IS
OBJ_HND CLIENT_OLE2.OBJ_TYPE := NULL;
mydocs CLIENT_ole2.obj_type;
-- Start Word97
PROCEDURE wordopen is                         
BEGIN
obj_hnd := null;
obj_hnd := CLIENT_OLE2.create_obj ('Word.Application');
CLIENT_OLE2.Set_property(obj_hnd,'Visible',1);
END;
PROCEDURE test is
BEGIN
IF obj_hnd IS NULL THEN
wordopen;
END IF;
BEGIN
mydocs := CLIENT_OLE2.get_obj_property(obj_hnd,'Documents');
EXCEPTION WHEN OTHERS THEN
-- Word has probably been closed by the user
-- so just start it again and retry...
wordopen;
mydocs := CLIENT_OLE2.get_obj_property(obj_hnd,'Documents');
END;
END;
END;
If the procedure test is called once then the Word application is started and the procedure performs some work. The procedure could be called several times on the same Word instance but fails in case the user closes the Word application because the procedure does not get an exception or error from WebUtil's get_obj_property function. Only a JACOB Java exception is logged in the Java console of the user's computer - the PL/SQL code has no way of knowing that an error has occurred.
Possible solution / patch for webutil.pll:
The webutil.pll can be patched to throw an exception if it is given an invalid object handle. In webutil.pll version 1.0.2 in get_object_property, line 1205, just add the condition "(v_javaHandle IS NULL) or " at the beginning of the if-statement in that line so that an OLE_ERROR will be raised if v_javaHandle is NULL:
if (v_javaHandle IS NULL) or (v_javaHandle = 0) or (v_javaHandle='') or (v_javaHandle=-1) then     
raise OLE_ERROR;      
end if;     
Can you confirm the error and re-release a patched webutil.pll at a later time?
Regards,
Andreas Leidner
infoteam GmbH Berlin

Answer 1

Hi
It is mentioned in webutil doc that, you must regenerate webutil.pll before using it; otherwise you’ll encounter error ORA-06508 when running a form with the attached library.
Hope this helps...
Regards,
Amatu Allah