Below is the syntax highlighted version of MM1Queue.java
from §1.3 Stacks and Queues.
/****************************************************************************** * Compilation: javac MM1Queue.java * Execution: java MM1Queue lambda mu * Dependencies: Queue.java Histogram.java * * Simulate an M/M/1 queue where arrivals and departures are Poisson * processes with arrival rate lambda and service rate mu. * * % java MM1Queue .20 .33 * * % java MM1Queue .20 .25 * * % java MM1Queue .20 .21 * * * Remarks * ------- * - We assume the interrarrival and service times are independent. * * ******************************************************************************/ public class MM1Queue { public static void main(String[] args) { double lambda = Double.parseDouble(args[0]); // arrival rate double mu = Double.parseDouble(args[1]); // service rate Queue<Double> q = new Queue<Double>(); // arrival times of customers double nextArrival = StdRandom.exp(lambda); // time of next arrival double nextDeparture = Double.POSITIVE_INFINITY; // time of next departure // histogram object Histogram hist = new Histogram(60); // simulate an M/M/1 queue while (true) { // it's an arrival if (nextArrival <= nextDeparture) { if (q.isEmpty()) nextDeparture = nextArrival + StdRandom.exp(mu); q.enqueue(nextArrival); nextArrival += StdRandom.exp(lambda); } // it's a departure else { double wait = nextDeparture - q.dequeue(); StdOut.printf("Wait = %6.2f, queue size = %d\n", wait, q.size()); hist.addDataPoint(Math.min(60, (int) (Math.round(wait)))); hist.draw(); if (q.isEmpty()) nextDeparture = Double.POSITIVE_INFINITY; else nextDeparture += StdRandom.exp(mu); } } } }