Question

Java: Hello, can someone please find a way to call my arraylist "list" and linkedhashmap called "jobMap" in my main method instead of calling them in the 2 classes? Also, is there a way to avoid the "Suppress Warning" portion in RoundRobin.java? I haven't been able to find a way for some reason. This is a job scheduling program, so the output should give the same values. To run: javac Main.java, java Main 5jobs.txt . txt file will be provided below.

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Main.java

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.Scanner;

public class Main{
public static void main(String[] args) throws IOException{

int time;
float turnaround;

Scanner scan = new Scanner(new File(args[0]));

// linkedhashmap used to maintain order jobs are read
LinkedHashMap jobs = new LinkedHashMap();

// reads each value, first the string (job title), then its value (time)
while(scan.hasNextLine()){
jobs.put(scan.nextLine(), Integer.parseInt(scan.nextLine()));
}

// checks for an empty file
if(jobs.isEmpty()){
System.out.println("ERROR: File is empty. Please try again.");
System.exit(0);
}

ShortestJobFirst sjf = new ShortestJobFirst();
RoundRobin rr = new RoundRobin();

sjf.shortestJobFirst(jobs, 0, 0);
rr.roundRobin(jobs, 0, 0, 2);
rr.roundRobin(jobs, 0, 0, 5);   
}

}

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ShortestJobFirst.java:

import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;

public class ShortestJobFirst{
public static void shortestJobFirst(LinkedHashMap jobs, int time, float turnaround){

System.out.println("Shortest-Job-First (SJF): \n");
System.out.println("Job\t\tStart Time\tEnd Time\tJob Description\n");

// specific method that sorts linkedhashmap by values in ascending order
LinkedHashMap jobMap = jobs.entrySet().stream()
.sorted(Map.Entry.comparingByValue())
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
(oldValue, newValue) -> oldValue, LinkedHashMap::new));

// displaying start times, calculating end time
for (String job : jobMap.keySet()){
System.out.print(job + "\t\t" + time + "\t\t");
time += jobs.get(job);
turnaround += time;
System.out.println(time + "\t\t" + job + " completed at time " + time);
}

// displaying average turnaround time
System.out.print("\nAverage turnaround time (SJF): ");
System.out.printf("%.2f / %d = %.2f", turnaround, jobs.keySet().size(), (turnaround/ jobs.keySet().size()));
System.out.println("\n**********************************************************************");
}

}

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RoundRobin.java

import java.util.ArrayList;
import java.util.LinkedHashMap;

public class RoundRobin{
@SuppressWarnings("unchecked")
public static void roundRobin(LinkedHashMap jobs, int time, float turnaround, int time_slice){

LinkedHashMap jobMap = (LinkedHashMap)jobs.clone();
ArrayList list = new ArrayList();

for (String job : jobs.keySet()) list.add(job);
   System.out.println("Round Robin with time slice = " + time_slice);
   System.out.println("Job\t\tStart Time\tEnd Time\tJob Description");

while (!list.isEmpty()) {

String job = (String)list.remove(0);
System.out.print(job + "\t\t" + time + "\t\t");

if ((Integer)jobMap.get(job) <= time_slice) {
time += (Integer)jobMap.get(job);
turnaround += time;
jobMap.put(job, 0);
System.out.println(time + "\t\t" + job + " completed at time " + time);
}else{
time += time_slice;
jobMap.put(job, (Integer)jobMap.get(job) - time_slice);
System.out.println(time);
list.add(job);
}
}

// displaying average turnaround time
System.out.print("\nAverage turnaround time (RR): ");
System.out.printf("%.2f / %d = %.2f", turnaround, jobs.keySet().size(), (turnaround/ jobs.keySet().size()));
System.out.println("\n**********************************************************************");
}

}

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5jobs.txt

Job1
10
Job2
5
Job3
8
Job4
18
Job5
12

Answer 1

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.Scanner;

class ShortestJobFirst {
    public static void shortestJobFirst(LinkedHashMap<String, Integer> jobMap, int time, float turnaround) {

        System.out.println("Shortest-Job-First (SJF): \n");
        System.out.println("Job\t\tStart Time\tEnd Time\tJob Description\n");

        // displaying start times, calculating end time
        for (String job : jobMap.keySet()) {
            System.out.print(job + "\t\t" + time + "\t\t");
            time += jobMap.get(job);
            turnaround += time;
            System.out.println(time + "\t\t" + job + " completed at time " + time);
        }

        // displaying average turnaround time
        System.out.print("\nAverage turnaround time (SJF): ");
        System.out.printf("%.2f / %d = %.2f", turnaround, jobMap.keySet().size(), (turnaround / jobMap.keySet().size()));
        System.out.println("\n**********************************************************************");
    }

}

class RoundRobin {
    public static void roundRobin(ArrayList<String> list, LinkedHashMap<String, Integer> jobs, int time, float turnaround, int time_slice) {

        Map<String, Integer> jobMap = jobs.entrySet()
                .stream().collect(Collectors.toMap(Map.Entry<String, Integer>::getKey, Map.Entry<String, Integer>::getValue));

        for (String job : jobs.keySet())
            list.add(job);
        
        System.out.println("Round Robin with time slice = " + time_slice);
        System.out.println("Job\t\tStart Time\tEnd Time\tJob Description");

        while (!list.isEmpty()) {

            String job = (String) list.remove(0);
            System.out.print(job + "\t\t" + time + "\t\t");

            if ((Integer) jobMap.get(job) <= time_slice) {
                time += (Integer) jobMap.get(job);
                turnaround += time;
                jobMap.put(job, 0);
                System.out.println(time + "\t\t" + job + " completed at time " + time);
            } else {
                time += time_slice;
                jobMap.put(job, (Integer) jobMap.get(job) - time_slice);
                System.out.println(time);
                list.add(job);
            }
        }

// displaying average turnaround time
        System.out.print("\nAverage turnaround time (RR): ");
        System.out.printf("%.2f / %d = %.2f", turnaround, jobs.keySet().size(), (turnaround / jobs.keySet().size()));
        System.out.println("\n**********************************************************************");
    }

}

public class Main {
    public static void main(String[] args) throws IOException {

        Scanner scan = new Scanner(new File(args[0]));

        // linkedhashmap used to maintain order jobs are read
        LinkedHashMap<String, Integer> jobs = new LinkedHashMap<>();

        // reads each value, first the string (job title), then its value (time)
        while (scan.hasNextLine()) {
            jobs.put(scan.nextLine(), Integer.parseInt(scan.nextLine()));
        }

        // checks for an empty file
        if (jobs.isEmpty()) {
            System.out.println("ERROR: File is empty. Please try again.");
            System.exit(0);
        }
        ArrayList<String> list = new ArrayList<>();

        // specific method that sorts linkedhashmap by values in ascending order
        LinkedHashMap<String, Integer> jobMap = jobs.entrySet().stream().sorted(Map.Entry.comparingByValue()).collect(Collectors
                .toMap(Map.Entry::getKey, Map.Entry::getValue, (oldValue, newValue) -> oldValue, LinkedHashMap::new));
        
        ShortestJobFirst.shortestJobFirst(jobMap, 0, 0);
        
        RoundRobin.roundRobin(list, jobs, 0, 0, 2);
        
        list.clear();
        RoundRobin.roundRobin(list, jobs, 0, 0, 5);

        scan.close();
    }

}

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