EDFScheduling.java

packagecom.thealgorithms.scheduling;

importjava.util.ArrayList;
importjava.util.Comparator;
importjava.util.List;

/**
 * The Earliest Deadline First (EDF) Scheduling class implements a dynamic scheduling algorithm.
 * It assigns the CPU to processes with the earliest deadlines, ensuring that deadlines are met if possible.
 * This scheduling algorithm is ideal for real-time systems where meeting deadlines is critical.
 */
publicfinalclassEDFScheduling {
privateEDFScheduling() {
 }

privateList<Process> processes;

/**
 * Constructs an EDFScheduling object with a list of processes.
 *
 * @param processes List of processes to be scheduled.
 */
publicEDFScheduling(finalList<Process> processes) {
this.processes = processes;
 }

/**
 * Schedules the processes using Earliest Deadline First (EDF) scheduling.
 * Processes are sorted by their deadlines, and the method simulates their execution.
 * It calculates the waiting time and turnaround time for each process.
 *
 * @return List of processes after they have been executed in order of earliest deadline first.
 */
publicList<Process> scheduleProcesses() {
processes.sort(Comparator.comparingInt(Process::getDeadline));

intcurrentTime = 0;
List<Process> executedProcesses = newArrayList<>();

for (Processprocess : processes) {
process.setWaitingTime(currentTime);
currentTime += process.getBurstTime();
process.setTurnAroundTime(process.getWaitingTime() + process.getBurstTime());

if (currentTime > process.getDeadline()) {
System.out.println("Warning: Process " + process.getProcessId() + " missed its deadline.");
 }

executedProcesses.add(process);
 }

returnexecutedProcesses;
 }

/**
 * The Process class represents a process with an ID, burst time, deadline, waiting time, and turnaround time.
 */
publicstaticclassProcess {
privateStringprocessId;
privateintburstTime;
privateintdeadline;
privateintwaitingTime;
privateintturnAroundTime;

publicProcess(StringprocessId, intburstTime, intdeadline) {
this.processId = processId;
this.burstTime = burstTime;
this.deadline = deadline;
 }

publicStringgetProcessId() {
returnprocessId;
 }

publicintgetBurstTime() {
returnburstTime;
 }

publicintgetDeadline() {
returndeadline;
 }

publicintgetWaitingTime() {
returnwaitingTime;
 }

publicvoidsetWaitingTime(intwaitingTime) {
this.waitingTime = waitingTime;
 }

publicintgetTurnAroundTime() {
returnturnAroundTime;
 }

publicvoidsetTurnAroundTime(intturnAroundTime) {
this.turnAroundTime = turnAroundTime;
 }
 }
}