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QuestionHow to catch new enent of OFFICE WORD Pin
yanshiqi21-Apr-03 16:10
yanshiqi21-Apr-03 16:10 
AnswerRe: How to catch new enent of OFFICE WORD Pin
Anonymous22-Apr-03 0:31
Anonymous22-Apr-03 0:31 
GeneralThreads in COM Pin
rattagarn18-Apr-03 1:16
rattagarn18-Apr-03 1:16 
GeneralRe: Threads in COM Pin
Imran_Farooqui18-Apr-03 1:23
sussImran_Farooqui18-Apr-03 1:23 
GeneralCOM server location on CLSID Pin
thowra17-Apr-03 23:30
thowra17-Apr-03 23:30 
GeneralRe: COM server location on CLSID Pin
Abebe28-Apr-03 23:08
Abebe28-Apr-03 23:08 
GeneralRe: COM server location on CLSID Pin
thowra29-Apr-03 3:13
thowra29-Apr-03 3:13 
GeneralApplication is still running or a crash occured Pin
ovidiu_pon17-Apr-03 22:07
ovidiu_pon17-Apr-03 22:07 
Hello,

Application
-----------
I've created a multi-tier application. Its architecture is:
On client machine --> the client application is an ActiveX EXE component (VBasic).
On server machine --> some COM+ server applications and a SQLServer database.


Use Case
--------
CLIENT1
--> asks SQLServer database for an object (= a row in objects table).
The state of this object is stored in a storage file.
--> if the object can be check out, it means nobody else have checked out the object,
the server will set the objects.checkedoutby = ClientID and will copy the stg file
in a shared folder on server machine.
CLIENT2
--> tries to check out the same object
--> the server must know (??? - MY QUESTION IS ABOUT THIS POINT) if the CLIENT1 application
is still running or a crash has occured and CLIENT1 was not able to check in the object.

Remarks
-------
1) CLIENT2 will receive a copy of the storage file if CLIENT1 is still running
2) CLIENT2 will have the possibility to restore the storage file from
an older version if a crash occured in the CLIENT1 application.
3) Many clients can log in using the same account (user name and password)
4) There can be more than one instances of the application on the same client machine

My solution
-----------
My solution is to create an instance of an "watchdog" ActiveX EXE on the client machine
when the client application is started. This "watchdog", from time to time (5 minutes by example),
will modify the value of a date field named NotificationDate in database.
When the client application shuts down, the "watchdog" will stop updating that field.
The stored procedure responsible for check out will use the value of NotificationDate field
to decide whether the CLIENT1 application that use this object is still running or a crash has occured.

Questions
---------
1) Is there a pattern for this problem?
2) What about my solution?

10x,
Ovidiu
GeneralOverloading an Interface Method in VC++ COM Pin
Vidya Ramani16-Apr-03 23:50
Vidya Ramani16-Apr-03 23:50 
GeneralRe: Overloading an Interface Method in VC++ COM Pin
safee ullah28-Apr-03 22:42
safee ullah28-Apr-03 22:42 
Generaldeskband and changing viewmode Pin
maos16-Apr-03 5:58
maos16-Apr-03 5:58 
GeneralRe: deskband and changing viewmode Pin
J. Dunlap16-Apr-03 8:46
J. Dunlap16-Apr-03 8:46 
GeneralGet COM object's instance handle Pin
thowra14-Apr-03 16:36
thowra14-Apr-03 16:36 
GeneralRe: Get COM object's instance handle Pin
Hans Ruck23-Apr-03 5:32
Hans Ruck23-Apr-03 5:32 
Generalmeaning of HRESULTs in Office Automation Pin
moredip14-Apr-03 12:00
moredip14-Apr-03 12:00 
Questionhow to get client's icon? Pin
mojimejl12-Apr-03 5:06
mojimejl12-Apr-03 5:06 
AnswerRe: how to get client's icon? Pin
pba_13-Apr-03 7:40
pba_13-Apr-03 7:40 
AnswerRe: how to get client's icon? Pin
Brian Shifrin13-Apr-03 17:41
Brian Shifrin13-Apr-03 17:41 
Questioni am new in COM: what are COMs ? Pin
Sendel11-Apr-03 15:53
Sendel11-Apr-03 15:53 
AnswerRe: i am new in COM: what are COMs ? Pin
Michael Dunn11-Apr-03 16:20
sitebuilderMichael Dunn11-Apr-03 16:20 
GeneralRe: i am new in COM: what are COMs ? Pin
Sendel11-Apr-03 16:40
Sendel11-Apr-03 16:40 
General_RecordsetPtr Detach / Debug Exception Pin
Ecator11-Apr-03 6:52
Ecator11-Apr-03 6:52 
GeneralRe: _RecordsetPtr Detach / Debug Exception Pin
pba_13-Apr-03 7:31
pba_13-Apr-03 7:31 
GeneralRe: _RecordsetPtr Detach / Debug Exception Pin
Ecator13-Apr-03 17:53
Ecator13-Apr-03 17:53 
GeneralRe: _RecordsetPtr Detach / Debug Exception Pin
pba_14-Apr-03 4:11
pba_14-Apr-03 4:11 

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