1. #include <omnetpp.h>
2. //using namespace omnetpp; //for Omnet++ ver. 5
3.  
4. class Server : public cSimpleModule
5. {  
6.   private:
7.     cQueue queue;             //the queue of jobs; it is assumed that the first job in the queue is the one being serviced
8.  cMessage *departure;        //special message; it reminds about the end of service and the need for job departure
9.  simtime_t departure_time;   //time of the next departure
10.  int bufforSize;
11.  int lostPackages = 0;
12.  int packages = 0;
13.  int lostPackegesOneByOne = 0;
14.  
15.  simtime_t overflowTime;
16.  cDoubleHistogram hisOverflowTime;
17.  cLongHistogram hisOverflowTimeOneByOne;
18.  
19.  
20.   protected:
21.     virtual void initialize();
22.     virtual void handleMessage(cMessage *msgin);
23.  
24. };
25.  
26. Define_Module(Server);
27.  
28.  
29. void Server::initialize()
30. {
31.  departure = new cMessage("Departure");
32.  bufforSize = par("buffor_size");
33.  //hisOverflowTime.setRange(0, 2.5);
34. }
35.  
36.  
37. void Server::handleMessage(cMessage *msgin)  //two types of messages may arrive: a job from the source, or the special message initiating job departure
38. {  
39.     if (msgin==departure)   //job departure
40.  {
41.   cMessage *msg = (cMessage *)queue.pop();    //remove the finished job from the head of the queue
42.   send(msg,"out");
43.  
44.  
45.   if(queue.length() == bufforSize - 1){
46.  
47.       hisOverflowTime.collect(simTime() - overflowTime);
48.  
49.       if(lostPackegesOneByOne != 0){
50.           hisOverflowTimeOneByOne.collect(lostPackegesOneByOne);
51.       }
52.   }
53.  
54.  
55.  
56.   if (!queue.isEmpty())                         //if the queue is not empty, initiate the next service, i.e. schedule the next departure event in the future
57.   {
58.    departure_time=simTime()+par("service_time");
59.          scheduleAt(departure_time,departure);
60.   }
61.  }
62.  else                    //job arrival
63.  {
64.      packages++;
65.  
66.   if (queue.isEmpty())  //if the queue is empty, the job that has just arrived has to be served immediately, i.e. the departure event of this job has to be scheduled in the future
67.   {
68.    departure_time=simTime()+par("service_time");
69.             scheduleAt(departure_time,departure);
70.   }
71.   if(queue.length() < bufforSize){
72.  
73.       queue.insert(msgin); //insert the job at the end of the queue
74.  
75.       if(queue.length() == bufforSize){
76.           overflowTime = simTime();
77.       }
78.       else{
79.            lostPackeges
80.       }
81.   }else{
82.       lostPackages++;
83.       delete msgin;
84.       lostPackegesOneByOne++;
85.   }
86.  
87.   double L = (lostPackages * 1.0) / packages;
88.   ev << "L = " << L;
89.  }
90. }
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