/* ------------------------------------------------------------------------- * This program simulates a single-server FIFO service node using arrival * times and service times read from a text file.  The server is assumed * to be idle when the first job arrives.  All jobs are processed completely * so that the server is again idle at the end of the simulation.   The * output statistics are the average interarrival time, average service * time, the average delay in the queue, and the average wait in the service  * node.  * * Name              : Ssq1.java  (Single Server Queue, version 1) * Authors           : Steve Park & Dave Geyer * Translated by     : Jun Wang & Richard Dutton * Language          : Java * Latest Revision   : 6-16-06 * Program ssq1      : Section 1.2 * -------------------------------------------------------------------------  */import java.io.*;import java.util.*;import java.text.*;class Ssq1Sum {                                 /* sum of ...           */  double delay;                                 /*   delay times        */  double wait;                                  /*   wait times         */  double service;                               /*   service times      */  double interarrival;                          /*   interarrival times */  void initSumParas() {    delay = 0.0;    wait = 0.0;    service = 0.0;    interarrival = 0.0;  }}class Ssq1 {  static String FILENAME = "Ssq1.dat";          /* input data file */  static double START = 0.0;  public static void main(String[] args) throws IOException {          FileInputStream fis = null;    try {      fis = new FileInputStream(FILENAME);    } catch (FileNotFoundException fnfe) {      System.out.println("Cannot open input file" + FILENAME);      System.exit(1);    }          InputStreamReader r = new InputStreamReader(fis);    BufferedReader in = new BufferedReader(r);    try {      String line = null;      StringTokenizer st = null;      long   index     = 0;                     /* job index            */      double arrival   = START;                 /* arrival time         */      double delay;                             /* delay in queue       */      double service;                           /* service time         */      double wait;                              /* delay + service      */      double departure = START;                 /* departure time       */      Ssq1Sum sum = new Ssq1Sum();      sum.initSumParas();      while ( (line = in.readLine()) != null ) {        index++;        st = new StringTokenizer(line);        arrival = Double.parseDouble(st.nextToken());        if (arrival < departure)          delay    = departure - arrival;       /* delay in queue    */        else          delay    = 0.0;                       /* no delay          */        service = Double.parseDouble(st.nextToken());        wait         = delay + service;        departure    = arrival + wait;          /* time of departure */        sum.delay   += delay;        sum.wait    += wait;        sum.service += service;      }      sum.interarrival = arrival - START;      DecimalFormat f = new DecimalFormat("###0.00");      System.out.println("\nfor " + index + " jobs");      System.out.println("   average interarrival time =  " + f.format(sum.interarrival / index));      System.out.println("   average service time .... =  " + f.format(sum.service / index));      System.out.println("   average delay ........... =  " + f.format(sum.delay / index));      System.out.println("   average wait ............ =  " + f.format(sum.wait / index));    } catch (EOFException eofe) {      System.out.println("Ssq1:" + eofe);    }    // if the file opened okay, make sure we close it     fis.close();  }    }