Webutil, read registry with defaut entry?

Question

webutil, read registry not working well?
Hi,
I cannot read the default value for an entry in the registry.
if I read another value, it works fine.
On metalink, a note was giving an exemple that was doing that... but it doesn't work when I try it....
Doc ID:      Note:121909.1
Subject:      How to Open a File with its Associated Program from Forms ?
Here is my code, the first block works, but the others don't work. Could somebody explain me how do I do to access the default value?
PROCEDURE P_TEST IS
lv_valeur_retour1 VARCHAR2(255);
BEGIN
BEGIN
-- this works fine
lv_valeur_retour1 :=
CLIENT_WIN_API_ENVIRONMENT.READ_REGISTRY
('HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows',
'Device',
TRUE);
message(lv_valeur_retour1);
pause;
EXCEPTION
WHEN NO_DATA_FOUND THEN
:F_RETOUR := '10';
END;
pause;
BEGIN
-- this doesn't work
lv_valeur_retour1 :=
CLIENT_WIN_API_ENVIRONMENT.READ_REGISTRY
('HKEY_CLASSES_ROOT\' || '.doc',
NULL,
TRUE);
message(lv_valeur_retour1);
pause;
EXCEPTION
WHEN NO_DATA_FOUND THEN
:F_RETOUR := '11';
END;
pause;
BEGIN
-- this doesn't work
lv_valeur_retour1 :=
CLIENT_WIN_API_ENVIRONMENT.READ_REGISTRY
('HKEY_CLASSES_ROOT\' || '.doc',
'Default',
TRUE);
message(lv_valeur_retour1);
pause;
EXCEPTION
WHEN NO_DATA_FOUND THEN
:F_RETOUR := '12';
END;
pause;
BEGIN
-- this doesn't work
lv_valeur_retour1 :=
CLIENT_WIN_API_ENVIRONMENT.READ_REGISTRY
('HKEY_CLASSES_ROOT\' || '.doc',
'(Default)',
TRUE);
message(lv_valeur_retour1);
pause;
EXCEPTION
WHEN NO_DATA_FOUND THEN
:F_RETOUR := '15';
END;
pause;
BEGIN
-- this doesn't work
lv_valeur_retour1 :=
CLIENT_WIN_API_ENVIRONMENT.READ_REGISTRY
('HKEY_CLASSES_ROOT\' || '.doc',
'0',
TRUE);
message(lv_valeur_retour1);
pause;
EXCEPTION
WHEN NO_DATA_FOUND THEN
:F_RETOUR := '14';
END;
pause;
BEGIN
-- this doesn't work
lv_valeur_retour1 :=
CLIENT_WIN_API_ENVIRONMENT.READ_REGISTRY
('HKEY_CLASSES_ROOT',
'.doc',
TRUE);
message(lv_valeur_retour1);
pause;
EXCEPTION
WHEN NO_DATA_FOUND THEN
:F_RETOUR := '13';
END;
END;

Answer 1

I had to customize the webutil.pll to get this to work. I modified the WEBUTIL_C_API.ADD_PARAMETER_WU function so it did not always consume null string parameters. The change follows.
FUNCTION ADD_PARAMETER_WU (paramList IN ParameterList, parameterType IN PLS_INTEGER,
inOut IN PLS_INTEGER, str IN VARCHAR2, strmaxlen IN PLS_INTEGER) RETURN ParameterHandle IS
paramHnd ParameterHandle;
BEGIN
     IF (str = 'mjpNULLmjp') THEN
                    WebUtil_Core.SetProperty(WebUtil_Core.WUL_PACKAGE,'WUL_PARAM_PROPERTIES', 'B|' -- indicate Bind
          || TO_CHAR(paramList.hnd) || '|'
          || TO_CHAR(parameterType) || '|'
          || TO_CHAR(inOut) || '|'
          || TO_CHAR(strmaxlen) || '|'
          || '',false);
     ELSE
          IF str IS NULL THEN
          WebUtil_Core.SetProperty(WebUtil_Core.WUL_PACKAGE,'WUL_PARAM_PROPERTIES', 'B|' -- indicate Bind
          || TO_CHAR(paramList.hnd) || '|'
          || TO_CHAR(parameterType) || '|'
          || TO_CHAR(inOut) || '|'
          || TO_CHAR(strmaxlen) || '|'
          || '(null)',false);
     ELSE          
          WebUtil_Core.SetProperty(WebUtil_Core.WUL_PACKAGE,'WUL_PARAM_PROPERTIES', 'B|' -- indicate Bind
          || TO_CHAR(paramList.hnd) || '|'
          || TO_CHAR(parameterType) || '|'
          || TO_CHAR(inOut) || '|'
          || TO_CHAR(strmaxlen) || '|'
          || str,false);
     END IF;
     END IF;
     paramHnd.hnd := TO_NUMBER(WebUtil_Core.GetProperty(WebUtil_Core.WUL_PACKAGE,'WUL_ADD_PARAMETER'));
     RETURN paramHnd;
EXCEPTION
when WebUtil_Core.BEAN_NOT_REGISTERED then
WebUtil_Core.Error(15,WebUtil_Core.getImplClass(WebUtil_Core.WUF_PACKAGE));               
RAISE FORM_TRIGGER_FAILURE;
when WebUtil_Core.PROPERTY_ERROR then
RAISE FORM_TRIGGER_FAILURE;
END ADD_PARAMETER_WU;
Here is an example call to get the default registry entry:
reg_val := CLIENT_WIN_API_ENVIRONMENT.READ_REGISTRY('HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\IEXPLORE.EXE','mjpNULLmjp',FALSE);