FCFSScheduling.java

package algorithms;

import java.util.Arrays;
import java.util.Comparator;

public class FCFSScheduling {

	public void schedule(Process[] processes) {
		// Sort processes by arrival time
		Arrays.sort(processes, Comparator.comparingInt(p -> p.arrivalTime));

		int currentTime = 0;

		for (Process process : processes) {
			// If arrival time is later than current time, advance time
			if (process.arrivalTime > currentTime) {
				currentTime = process.arrivalTime;
			}

			process.startTime = currentTime;
			currentTime += process.burstTime;
			process.completionTime = currentTime;
			process.turnAroundTime = process.completionTime
					- process.arrivalTime;
			process.waitingTime = process.turnAroundTime - process.burstTime;
		}
	}

	// Calculate and return average waiting time
	public double getAverageWaitingTime(Process[] processes) {
		double totalWaitingTime = 0;
		for (Process p : processes) {
			totalWaitingTime += p.waitingTime;
		}
		return totalWaitingTime / processes.length;
	}

	// Calculate and return average turnaround time
	public double getAverageTurnaroundTime(Process[] processes) {
		double totalTurnaroundTime = 0;
		for (Process p : processes) {
			totalTurnaroundTime += p.turnAroundTime;
		}
		return totalTurnaroundTime / processes.length;
	}
}