implemeting an active alarm table

[Frank Fock]

Hi Dave,

Please find my comments inline:

Dave Mason wrote:
> Hi,
> I'm building a table to maintain a list of currently active alarms. This 
> table must be persistent.  That is, if I shut down my agent and restart 
> it, I need the table to contain the same rows that it had before.  Does 
> the MibTable class give me this behavior, or do I need to use a 
> StorageTable?  The MIB definition for the table does not have a 

Every MibTable has support for persistency. It is activated, when
you add your table to a MibGroup which is then added to a MibInstance
with a configured persistency directory.
So while your table does not have a StorageType column, it does
not make sense to inherit from StorageTable.

> StorageType column, but I could make one behind the scenes if I needed 
> to.  Also, I have a scalar MIB object associated with the table to 
> record a timestamp whenever the alarm table changes (whenever a row is 
> added or deleted.)  Does this mean I need to subclass the table off of 
> TimeStampTable and use its timestamp?  Maybe I need to inherit from both 
It could save you some implementation effort to do so (inherit from
TimeStampTable only), but it is not a must.

> (hopefully not the case), or I need to make my own subclass that does 
> both.  I suspect it may be easier to just manage the timestamp object 
> myself, but I wanted to make sure I wasnt missing anything.  I use 
> AgentGen Pro to make my table class - now it just inherits from MibTable 
> but I could change that.
> 
> Also, I'm a little rusty on tables.  This table does not have a 
> RowStatus column, so does the logic to create it and add/delete rows 
> look something like this?
> 
> create:
> activeAlarmEntry *aae = new activeAlarmEntry();
> or can I just use activeAlarmEntry::instance instead of making a new 
> object?
You need to create a activeAlarmEntry instance exactly once,
then you can use activeAlarmEntry::instance for further operations.

> 
> add/delete:
> Oidx indexOid("1"); // my index is an Unsigned32
> MibTableRow* row = aae->instance->add_row(indexOid);
> aae->set_row(row, ...columnar object values...);
> or
> row = result of search for row with columns equal to desired values
> aae->remove_row(row);
> 
That's OK.

> Just a couple more questions.  (Hope this isnt too long. :)  When do I 
> need to call mib.add(), if at all?  If I do, do I need to update mib

mib.add(..) is used to register your MIB objects with the dispatcher.
So you need to call it for every MibGroup and for every unmanaged
(regarding persistency) MIB object instance (MibLeaf, MibTable, etc.).

> when I delete a row?  And here's the last - do I need to manage the 
No, you do not need to update Mib when you delete a row.

> index myself, or is there a way to have the table object just use the 
> next higher one when adding a row?  If so, I'll need a way to know what 
> the index was.
For simple indecies MibTable::get_next_avail_index() will do the job.

Best regards,
Frank