Currently, I have a program which simulates a shortest job first strategy for a set of processes. However, my task is to make it for multi-priority level queues. So a queue for HIGH, MILD, LOW: HIGH = 1, MILD = 2, LOW = 3. The original code works fine and now I am stuck with trying to implement it for the 3 separate process queues. I have managed to add the correct processes into each queue but there's as far as I got to. The problem is, how do I apply the SJF strategy to each queue
import java.util.ArrayList;import java.util.Collections;import java.util.List;public class TEST{ List<Process> processList; List<Process> highPriorityQueue; List<Process> mildPriorityQueue; List<Process> lowPriorityQueue; List<Process> finalProcessList; private int count; private int timeQuantum; int j=0; private int ganntP[]; private int ganntT[]; private int totalWaitingTime=0; private int totalTurnAroundTime=0; private float avgWatingTime=0; private float avgTurnaroundTime=0; TEST(List<Process> processList) { count=processList.size(); this.timeQuantum=timeQuantum; this.processList=new ArrayList<Process>(); this.highPriorityQueue=new ArrayList<Process>(); this.mildPriorityQueue=new ArrayList<Process>(); this.lowPriorityQueue=new ArrayList<Process>(); this.finalProcessList = new ArrayList<Process>(); ganntT=new int[200]; ganntP=new int[200]; for(Process p : processList) { if(p.getPriority()==1) this.highPriorityQueue.add(new Process(p.getProcessId(), p.getArrivalTime(), p.getBurstTime(),p.getPriority())); else if(p.getPriority()==2) this.mildPriorityQueue.add(new Process(p.getProcessId(), p.getArrivalTime(), p.getBurstTime(),p.getPriority())); else if(p.getPriority()==3) this.lowPriorityQueue.add(new Process(p.getProcessId(), p.getArrivalTime(), p.getBurstTime(),p.getPriority())); } Collections.sort(highPriorityQueue, Process.BY_ARRIVAL_TIME); Collections.sort(highPriorityQueue, Process.BY_BURST_TIME); Collections.sort(mildPriorityQueue, Process.BY_ARRIVAL_TIME); Collections.sort(mildPriorityQueue, Process.BY_BURST_TIME); Collections.sort(lowPriorityQueue, Process.BY_ARRIVAL_TIME); Collections.sort(lowPriorityQueue, Process.BY_BURST_TIME); // CREATE NEW QUEUE WITH COMBINED PRIORITIES IN ORDER // SEE WHAT PROBLEM IS // CHECK SJF WHY NOT WORKING //finalProcessList.addAll(highPriorityQueue); //finalProcessList.addAll(mildPriorityQueue); //finalProcessList.addAll(lowPriorityQueue); } /*public void simulate() { int currentTime=0; int remainingProcess=count; while (remainingProcess > 0) { int min=1000; int index=-1; Process current = null; for (int i = 0; i < count; i++) { current = processList.get(i); if (current.getRemainingTime() > 0 && current.getBurstTime()<min &¤t.getArrivalTime()<=currentTime ) { index=i; min=current.getBurstTime(); } } if(index==-1) { currentTime++; continue; } current = processList.get(index); if (current.getStartTime()==-1) { current.setStartTime(currentTime); } ganntP[j]=current.getProcessId(); ganntT[j]=currentTime; j++; current.setRemainingTime(0); current.setEndTime(currentTime +current.getBurstTime()); currentTime+=current.getBurstTime(); remainingProcess--; } for(int i=0;i<count;i++) { Process current=processList.get(i); current.setWaitingTime(current.getEndTime()-current.getBurstTime()-current.getArrivalTime()); current.setTurnaroundTime(current.getEndTime() - current.getArrivalTime()); totalWaitingTime+=current.getWaitingTime(); totalTurnAroundTime+=current.getTurnaroundTime(); } avgWatingTime=(float)totalWaitingTime/count; avgTurnaroundTime=(float)totalTurnAroundTime/count; }*/ public void printResult() { Collections.sort(this.processList, Process.BY_PROCESSID); System.out.println("Simulation result of TEST "); System.out.println("ProcessID | ArrivalTime | BurstTime | Priority | StartTime | EndTime| WaitingTime | TurnAroundTime"); System.out.println("PId ArrivalT BurstT Priority StartT EndT WaitingT TurnAroundT"); for(Process p : processList) { System.out.println(p); } System.out.println("Average Waiting Time of Multilevel "+avgWatingTime); System.out.println("Average TurnAround Time of Multilevel "+avgTurnaroundTime); System.out.println("HIGH PRIORITY"); System.out.println("PId ArrivalT BurstT Priority StartT EndT WaitingT TurnAroundT"); for(Process p : highPriorityQueue) { System.out.println(p); } System.out.println("MILD PRIORITY"); System.out.println("PId ArrivalT BurstT Priority StartT EndT WaitingT TurnAroundT"); for(Process p : mildPriorityQueue) { System.out.println(p); } System.out.println("LOW PRIORITY"); System.out.println("PId ArrivalT BurstT Priority StartT EndT WaitingT TurnAroundT"); for(Process p : lowPriorityQueue) { System.out.println(p); } for(int i=0;i<j;i++) { System.out.println("Time "+ganntT[i]+" Process "+ganntP[i]); } System.out.println(); System.out.println("LIST COMBINE TEST"); System.out.println("PId ArrivalT BurstT Priority StartT EndT WaitingT TurnAroundT"); for(Process p : finalProcessList) { System.out.println(p); } }}As you'll see the simulate method is commented out due to it being for the SJF strategy, here is where I need to change it to be able to work for all 3 queues I've created.
EDIT:In my brief it states I need to use shortest job first strategy for multi priority level queues - so my goal is to apply sjf to each queue, then find a way to avoid starvation to low/mild priorities
My final goal being: A scheudler which has multiple queues for each priority - each implementing shortest job first and a way to avoid starvation to low/mild priorities and avoid long wait time for long burst time processes