Not properly executed overridden code using an INET extended module

Question

I have to extend the UdpBasicApp module from INET4 in OMNeT++ 5.6.1 (Ubuntu 18.04.4) and execute two overridden methods (initialize and handleMessageWhenUp). It seems an easy task, and looked like it was all fine when I built the project (momentarily stored inside the "examples" folder in inet4) with no errors but, after starting the simulation the code isn't successfully overridden. The original code (the one from UdpBasicApp) is executed instead. In fact, after inspecting the code in the editor, the methods' name isn't bold (as should be) and the keywords aren't colored as they normally should be. My C++ skill is not high (nor my OMNeT one) hence I'm not sure what is really happening. The extended simple module is called "PriorityApp" (I added just an integer field more).

This is the .ned code (not sure if you need it)

package inet.examples.MyProject.src;

import inet.applications.udpapp.UdpBasicApp;

// The module extends UdpBasicApp adding a priority parameter
simple PriorityApp extends UdpBasicApp
{
    parameters:
        int priority = default(0);  // priority 0 = higher priority
}

This is the .h code

#ifndef __INET4_PRIORITYAPP_H_
#define __INET4_PRIORITYAPP_H_

#include "inet/applications/udpapp/UdpBasicApp.h"

namespace inet {

class PriorityApp : public UdpBasicApp
{
  protected:
    int priority;

    virtual void initialize(int stage) override;
    virtual void handleMessageWhenUp(cMessage *msg) override;
};

} // namespace inet

#endif  // ifndef __INET_PRIORITYAPP_H

This is the .cc code

#include "PriorityApp.h"

namespace inet {

Define_Module(PriorityApp);

void PriorityApp::initialize(int stage)
{
    msg = new cMessage("priority");
    EV << "Example Message" << endl;
}

void PriorityApp::handleMessageWhenUp(cMessage *msg)
{

}

} //namespace inet

This is the .ini file

[General]

[Config SwitchedNet1G]
description = "1Gbps Switched Network"
network = SwitchedNet

**.dataRate = 1Gbps                                         # 1 Gbps channel datarate

# Priority stuff
**.host[0].app[0].priority = 1

# Dst Params
**.sink.app[*].typename = "UdpSink"                         # Destination host (it receives messages)
**.sink.app[*].localPort = 2500

# Src Params
**.host[0].app[0].packetName = "Host0-Data"
**.host[*].app[0].typename = "PriorityApp"                  # Source host (they send messages)
**.host[*].app[0].destPort = 2500
**.host[*].app[0].destAddresses = "sink"
**.host[0].app[0].sendInterval = 3s
**.host[*].app[0].startTime = uniform (0s, 3s)

# EthInterface Setup
**.eth[*].qEncap.typename = "Ieee8021qEncap"                # 8021Q Encapsulation
**.etherSwitch.numEthInterfaces = 2                         # Switch ethInterfaces total number (2)
**.numEthInterfaces = 1

# Global Params
**.messageLength = 100B
**.numHosts = 1
**.numApps = 1                                  # every host has 1 app (UdpBasicApp or UdpSink)

Answer 1

There are two independent faults here:

1.) You should NOT add C++ code into INET's examples folder. That folder is NOT designated as a source folder, so the build system will not pick up, build and link to the executable, meaning that your code is not present in the model. That's one reason why you are not getting your new behavior.

2.) Even if you place your source code in the src folder along with the UdpBasicApp and the build system would properly link it in, you still have to properly set up the NED part. Specifically you have to specify the @class property to tell NED which C++ class you intend to use to specify behavior: @class(PriorityApp) Otherwise your PriorityApp module would inherit the value of @class property from UdpBasicApp and would use the CdpBasicApp C++ class.

import inet.applications.udpapp.UdpBasicApp;

// The module extends UdpBasicApp adding a priority parameter
simple PriorityApp extends UdpBasicApp
{
    @class(PriorityApp)
    parameters:
        int priority = default(0);  // priority 0 = higher priority
}