Hello, I have to make a Super Market Simulator in Java Script . I finished up th

Question

Hello, I have to make a Super Market Simulator in Java Script. I finished up the program but keep getting an error about my main class, Can someone help me fix my main class issue on this program below?

Thanks for the help!!!

Program so far:

package grocerystoresimulation;

import java.util.PriorityQueue;

import java.util.Random;

import java.util.ArrayList;

import java.util.Date;

import java.text.DateFormat;

import java.text.SimpleDateFormat;

public class GroceryStoreSimulation {

private PriorityQueue<Integer> pq = new PriorityQueue<Integer>();

private Random rand = new Random(); //instantiate new Random object   

private Date date = new Date();

private DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd - hh:mm:ss a");

private ArrayList<String> timeStamp = new ArrayList<String>(); //store timestamps

private int totalCustomers; //# of customers served during simulation

private long startTime = System.nanoTime(); //time of initial build

private long simulationTime = 1; //desired time in minutes

private long firstWaitTime = generateWaitTime();

private long serviceCustomerAt;

public GroceryStoreSimulation(){

System.out.println("Instantiated new GroceryStoreSimulation @ ["

+ dateFormat.format(date) + "] " + insertDivider());

} //GroceryStoreSimulation()

public void run(){

//Main program body

try {

Thread.sleep(firstWaitTime); //generate wait time for first customer

System.out.println("Delay until first customer: " + firstWaitTime);

newCustomer(totalCustomers);

serveCustomer();

} catch (InterruptedException e){/*Catch 'em all*/}

while((System.nanoTime()-startTime)<=(simulationTime*60000000000L)-firstWaitTime){

try {

newCustomer(totalCustomers); //enque customer

serveCustomer();

} catch(Exception e){/*Catch 'em all*/}

}

System.out.println("Exit");

System.exit(0); //stop runtime

} //run()

@Override

public String toString(){

return this.pq.toString();

}

private void serveCustomer(){

long elapsedTime = System.nanoTime()-startTime;

while((elapsedTime)<(serviceCustomerAt)){

elapsedTime += System.nanoTime()/10000000;

}

if(pq.size()!=0){

System.out.println("Dequeued customer @[" + dateFormat.format(new Date())

+ "]");

pq.poll(); //remove first element of queue

} else {

System.out.println("ERROR: Queue is empty!");

}

} //serveCustomer()

private void newCustomer(int ID){

long elapsedTime = System.nanoTime()-startTime;

long waitTime = (long)generateWaitTime()*1000000;

long generateAt = elapsedTime+waitTime;

while((elapsedTime)<(generateAt)){/*Wait*/   

elapsedTime += System.nanoTime()/10000000; //increment elapsed time

}   

serviceCustomerAt = 0; //reset service wait time value

System.out.println("Customer # " + totalCustomers + " added to queue. . .");

totalCustomers++;

pq.offer(ID); //insert element into PriorityQueue

System.out.println("Queue size: " + pq.size()); //output linesize

assignTimestamp(ID); //call assignArrivalTime() method

//Calculate time until customer served

waitTime = (long)generateWaitTime()*1000000;

elapsedTime = System.nanoTime()-startTime;

serviceCustomerAt = elapsedTime + waitTime;

System.out.println("Service delay: " + waitTime/1000000);

}

private void assignTimestamp(int ID){

timeStamp.add(ID + ": " + dateFormat.format(new Date()));

System.out.println(timeStamp.get(totalCustomers-1));

} //assignArrivalTime()

private int generateWaitTime(){

//Local variables

int Low = 1000; //1000ms

int High = 4000; //4000ms

return rand.nextInt(High-Low) + Low;

}

private static String insertDivider(){

return ("****");

}

}

Explanation / Answer

package grocerystoresimulation;

import java.util.PriorityQueue;
import java.util.Random;
import java.util.ArrayList;
import java.util.Date;
import java.text.DateFormat;
import java.text.SimpleDateFormat;

public class GroceryStoreSimulation
{

private PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
private Random rand = new Random(); //instantiate new Random object  

private Date date = new Date();
private DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd - hh:mm:ss a");
private ArrayList<String> timeStamp = new ArrayList<String>(); //store timestamps

private int totalCustomers; //# of customers served during simulation

private long startTime = System.nanoTime(); //time of initial build
private long simulationTime = 1; //desired time in minutes
private long firstWaitTime = generateWaitTime();
private long serviceCustomerAt;

/*
* @constuctor
*/
public GroceryStoreSimulation(){
    System.out.println("Instantiated new GroceryStoreSimulation @ ["
            + dateFormat.format(date) + "] " + insertDivider());
}
public void run()
{

    try {
        Thread.sleep(firstWaitTime); //generate wait time for first customer
        System.out.println("Delay until first customer: " + firstWaitTime);
        newCustomer(totalCustomers);
        serveCustomer();
    } catch (InterruptedException e)
    {}

    while((System.nanoTime()-startTime)<=(simulationTime*60000000000L)-firstWaitTime)
    {
        try {
            newCustomer(totalCustomers);
            serveCustomer();
        } catch(Exception e)
        {
        }
    }
    System.out.println("Exit");
    System.exit(0);
}

public String toString(){
    return this.pq.toString();
}

private void serveCustomer(){
    long elapsedTime = System.nanoTime()-startTime;
    while((elapsedTime)<(serviceCustomerAt)){
        elapsedTime += System.nanoTime()/10000000;
    }
    if(pq.size()!=0){
        System.out.println("Dequeued customer @[" + dateFormat.format(new Date())
                + "]");
        pq.poll(); //remove first element of queue
    } else {
        System.out.println("ERROR: Queue is empty!");
    }
} //serveCustomer()

/*
* @param String ID
*/
private void newCustomer(int ID){
    long elapsedTime = System.nanoTime()-startTime;
    long waitTime = (long)generateWaitTime()*1000000;
    long generateAt = elapsedTime+waitTime;

    while((elapsedTime)<(generateAt)){/*Wait*/  
        elapsedTime += System.nanoTime()/10000000; //increment elapsed time
    }    
    serviceCustomerAt = 0; //reset service wait time value
    System.out.println("Customer # " + totalCustomers + " added to queue. . .");
    totalCustomers++;
    pq.offer(ID); //insert element into PriorityQueue
    System.out.println("Queue size: " + pq.size()); //output linesize
    assignTimestamp(ID); //call assignArrivalTime() method

    //Calculate time until customer served
    waitTime = (long)generateWaitTime()*1000000;
    elapsedTime = System.nanoTime()-startTime;

    serviceCustomerAt = elapsedTime + waitTime;
    System.out.println("Service delay: " + waitTime/1000000);
} //newCustomer()

private void assignTimestamp(int ID){
    timeStamp.add(ID + ": " + dateFormat.format(new Date()));
    System.out.println(timeStamp.get(totalCustomers-1));
} //assignArrivalTime()

private int generateWaitTime(){
    //Local variables
    int Low = 1000; //1000ms
    int High = 4000; //4000ms
    return rand.nextInt(High-Low) + Low;
}

private static String insertDivider(){
    return ("****");
}

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