Server.java

class Server {

int Queue_size = 32000;
int next_event_type;
int num_custs_delayed;
int num_events=2;
int num_in_q;
int server_status;
int num_delays_required;
double area_num_in_q;
double area_server_status;
double sim_time;
double time_last_event;
double total_of_delays;
double mean_interarrival;
double mean_service;
 
double[] time_arrival = new double[Queue_size];;
double[] time_next_event=new double[3];
 
void initialize() {

sim_time = 0;
server_status = 0;
num_in_q = 0;
time_last_event = 0;
 
num_custs_delayed = 0;
total_of_delays = 0;
area_num_in_q = 0;
area_server_status = 0;
 
time_next_event[1] = sim_time + MultiServerQueueingSystem.expon(mean_interarrival) ;
time_next_event[2] = 1.0e+30;
}


void timing() {

int   i;
double min_time_next_event = 1.0e+29;
 
next_event_type = 0;
 
for (i = 1; i <= num_events; ++i) { 

if (time_next_event[i] < min_time_next_event) {
min_time_next_event = time_next_event[i];
next_event_type = i;
}
}
 
 
if (next_event_type == 0) {
System.out.println("\nEvent list empty at time"+ sim_time);
}
 
sim_time = min_time_next_event;
}

void arrive(double time) {
double delay;
 
time_next_event[1] = time;
 
if (server_status == 1) {
num_in_q++;
time_arrival[num_in_q] = sim_time;
}
 
else {
delay = 0;
total_of_delays += delay;
 
num_custs_delayed++;
server_status = 1;
 
time_next_event[2] = sim_time + MultiServerQueueingSystem.expon(mean_service);
}
}

void depart() {
int   i;
double delay;
 
if (num_in_q == 0) {
server_status = 0;
time_next_event[2] = 1.0e+30;
}
 
else {
num_in_q--;
 
delay = sim_time - time_arrival[1];
total_of_delays += delay;
 
num_custs_delayed++;
time_next_event[2] = sim_time + MultiServerQueueingSystem.expon(mean_service);
 
for (i = 1; i <= num_in_q; i++)
time_arrival[i] = time_arrival[i + 1];
}
}
 
void report() {
System.out.println( "TOtal customer uses this server " + num_custs_delayed + "\n");
System.out.println( "Average delay in queue minutes  " + total_of_delays / num_custs_delayed + "\n");
System.out.println( "Average number in queue  " + area_num_in_q / sim_time + "\n");
System.out.println( "Server utilization  " + area_server_status / sim_time + "\n");
}

void update_time_avg_stats()
{
double time_since_last_event;
 
time_since_last_event = sim_time - time_last_event;
time_last_event = sim_time;
 
area_num_in_q += num_in_q * time_since_last_event;
 
area_server_status += server_status * time_since_last_event;
}
}