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omnet++

Update parameter value in XML format

I have parameters stored in an XML file. Below is a sample of the file.

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <terminal id="A">
      <terminalCapacity>3</terminalCapacity>
      <terminalMembers id="1">
            <memberID>0001</memberID>
            <memberCapacity>2</memberCapacity>
      </terminalMembers>
    </terminal>
    <terminal id="B">
      <terminalCapacity>4</terminalCapacity>
      <terminalMembers id="1">
          <memberID>0002</memberID>
          <memberCapacity>1</memberCapacity>
      </terminalMembers>
      <terminalMembers id="2">
          <memberID>0003</memberID>
          <memberCapacity>3</memberCapacity>
      </terminalMembers>
    </terminal>
</root>

Each terminalID is associated to a type of simpleModule found in my NED file. The idea is to programmatically update these values throughout the simulation run. The current logic revolves around getting the current parameters in XML format and update the memberCapacity field.

From the Omnet cPar and cXMLElement documentation, I tried using the par("moduleParameter").xmlValue()->getXML() function, but this returns the XML as a string. I also tried using the getAttribute() function, but to no success.

Solution

  • Don't do this. par("moduleParameter").xmlValue() will give you the in memory object tree of the XML document, but that is not meant for modification. Your XML file seems to be just a hierarchical structure and modules and their parameters can mirror that exactly. There is absolutely no reason to reinvent the wheel when you can mirror that with INI file parameters.