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

[Marek Hajduczenia]

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