[SNMP4J] Updating registered managed objects (adding rows to MIB table)

[Marek Hajduczenia]

Hi Frank, 

 

thanks for the quick feedback. I must have not been really clear in my
explanation and I apologize for that. What I want to achieve is not to add
new rows into the table definition, but add new entries (new rows using
addRowValue command) into the table. 

 

In other words, how do I add row values (addRowValue) to builder after
having executed 

 

server.registerManagedObject(builder.build());

 

? 

 

When I try to add row values using builder.addRowValue and then register the
MO again, I get exception (quite expected, it is registered already)

 

Thanks again 

 

Marek

 

> Hi,

> 

> The answer is very simple: Just add rows to the table (i.e. its table 

> model).

> You can do this while the table itself is registered (operation is 

> thread safe).

> 

> Best regards,

> Frank

> 

 


Subject: Updating registered managed objects (adding rows to MIB table)

 

Dear all, 

 

I am writing a small SNMP related project for my course. The task is to
create an SNMP agent that will monitor a local selected folder and list all
files stored in this folder in a MIB. I have already MIB designed, agent
working fine on the initial pass, i.e., it creates a MIB table, populates
initial values (files found at first pass through the folder) and then
registers MIB with the agent. 

 

The code snippet building the table structure is shown below:

 

MOTableBuilder builder = new MOTableBuilder(oidNewRoot);

                                                

// MIB structure

                                

builder.addColumnType(SMIConstants.SYNTAX_INTEGER32,MOAccessImpl.ACCESS_READ
_ONLY);

builder.addColumnType(SMIConstants.SYNTAX_OCTET_STRING,MOAccessImpl.ACCESS_R
EAD_ONLY);

builder.addColumnType(SMIConstants.SYNTAX_INTEGER,MOAccessImpl.ACCESS_READ_O
NLY);             

builder.addColumnType(SMIConstants.SYNTAX_OCTET_STRING,MOAccessImpl.ACCESS_R
EAD_ONLY);                                               

builder.addColumnType(SMIConstants.SYNTAX_INTEGER32,MOAccessImpl.ACCESS_READ
_ONLY);                                        

builder.addColumnType(SMIConstants.SYNTAX_INTEGER32,MOAccessImpl.ACCESS_READ
_ONLY);                                        

builder.addColumnType(SMIConstants.SYNTAX_OCTET_STRING,MOAccessImpl.ACCESS_R
EAD_ONLY);                                               

builder.addColumnType(SMIConstants.SYNTAX_OCTET_STRING,MOAccessImpl.ACCESS_R
EAD_ONLY);                                               

builder.addColumnType(SMIConstants.SYNTAX_INTEGER32,MOAccessImpl.ACCESS_READ
_ONLY);                                        

builder.addColumnType(SMIConstants.SYNTAX_INTEGER,MOAccessImpl.ACCESS_READ_W
RITE);

 

The code snippet adding a row is shown below (it is repeated in a loop to
add all found files):

 

builder.addRowValue(new Integer32(index));

index++;

builder.addRowValue(new OctetString(fileName.getName()));

builder.addRowValue(new Integer32(3));

builder.addRowValue(new OctetString(fileName.getPath()));

builder.addRowValue(new Integer32((int)fileName.length()));

builder.addRowValue(new Integer32(323));

builder.addRowValue(new OctetString("Artista"));

builder.addRowValue(new OctetString("Album"));

builder.addRowValue(new Integer32(1980));

builder.addRowValue(new Integer32(4));

 

Finally, I register the new MIB with the agent:

 

server.registerManagedObject(builder.build());

 

After that, I run agent on a loop, every 5 seconds checking whether a new
file was added to the folder. When that happens, I can detect a new file
added and create list of such files. However, I do not know (could not find
any information) on how to add row to already registered MIB. One thought
was on reusing previously constructed table and just deregister it, then add
new rows as needed and the register again but it seems like a very crude
solution to me. Is there any way to do that better? if so, I would
appreciate any pointers. 

 

Thank you in advance

 

Marek