java.io.FileNotFoundException, why?

Question

I have downloaded the SSJ library, a Java library for stochastic simulation. One of the files needs to open a *.dat file.

I am trying to run the file as downloaded, and the dat file is also there but I get the FileNotFoundException everytime.

Here's the source code:

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.StringTokenizer;
import umontreal.iro.lecuyer.randvar.ExponentialGen;
import umontreal.iro.lecuyer.rng.MRG32k3a;
import umontreal.iro.lecuyer.rng.RandomStream;
import umontreal.iro.lecuyer.simevents.Event;
import umontreal.iro.lecuyer.simevents.Sim;
import umontreal.iro.lecuyer.simprocs.Resource;
import umontreal.iro.lecuyer.simprocs.SimProcess;
import umontreal.iro.lecuyer.stat.Tally;

public final class Jobshop {
   int nbMachTypes;       // Number of machine types M.
   int nbTaskTypes;       // Number of task types N.
   double warmupTime;     // Warmup time T_0.
   double horizonTime;    // Horizon length T.
   boolean warmupDone;    // Becomes true when warmup time is over.
   Resource[] machType;   // The machines groups as resources.
   Jobshop.TaskType[] taskType;   // The task types.
   RandomStream streamArr = new MRG32k3a(); // Stream for arrivals.
   BufferedReader input;

   public Jobshop() throws IOException { readData(); }

   // Reads data file, and creates machine types and task types.
   void readData() throws IOException {
 // input = new BufferedReader (new FileReader ("Jobshop.dat"));
  input = new BufferedReader (new FileReader ("JobShop.dat"));
  StringTokenizer line = new StringTokenizer (input.readLine());
  warmupTime = Double.parseDouble (line.nextToken());
  line = new StringTokenizer (input.readLine());
  horizonTime = Double.parseDouble (line.nextToken());
  line = new StringTokenizer (input.readLine());
  nbMachTypes = Integer.parseInt (line.nextToken());
  nbTaskTypes = Integer.parseInt (line.nextToken());
  machType = new Resource[nbMachTypes];
  for (int m=0; m < nbMachTypes; m++) {
     line = new StringTokenizer (input.readLine());
     String name = line.nextToken();
     int nb = Integer.parseInt (line.nextToken());
     machType[m] = new Resource (nb, name);
  }
  taskType = new Jobshop.TaskType[nbTaskTypes];
  for (int n=0; n < nbTaskTypes; n++)
     taskType[n] = new Jobshop.TaskType();
  input.close();
}


class TaskType {
  public String     name;        // Task name.
  public double     arrivalRate; // Arrival rate.
  public int        nbOper;      // Number of operations.
  public Resource[] machOper;    // Machines where operations occur.
  public double[]   lengthOper;  // Durations of operations.
  public Tally      statSojourn; // Stats on sojourn times.

  // Reads data for new task type and creates data structures.
  TaskType() throws IOException {
     StringTokenizer line = new StringTokenizer (input.readLine());
     statSojourn = new Tally (name = line.nextToken()); 
     arrivalRate = Double.parseDouble (line.nextToken());
     nbOper = Integer.parseInt (line.nextToken());
     machOper = new Resource[nbOper];
     lengthOper = new double[nbOper];
     for (int i = 0; i < nbOper; i++) {
        int p = Integer.parseInt (line.nextToken());
        machOper[i] = machType[p-1];
        lengthOper[i] = Double.parseDouble (line.nextToken());
     }
  }

  // Performs the operations of this task (to be called by a process).
  public void performTask (SimProcess p) {
     double arrivalTime = Sim.time();
     for (int i=0; i < nbOper; i++) {
        machOper[i].request (1); p.delay (lengthOper[i]);
        machOper[i].release (1);
     }
     if (warmupDone) statSojourn.add (Sim.time() - arrivalTime);
  }
}

public class Task extends SimProcess {
  Jobshop.TaskType type;

  Task (Jobshop.TaskType type) { this.type = type; }

  public void actions() { 
  // First schedules next task of this type, then executes task.
     new Jobshop.Task (type).schedule (ExponentialGen.nextDouble
           (streamArr, type.arrivalRate));
     type.performTask (this);
  }
}

Event endWarmup = new Event() {
  public void actions() {
     for (int m=0; m < nbMachTypes; m++)
        machType[m].setStatCollecting (true);
     warmupDone = true;
  }
};

Event endOfSim = new Event() {
    @Override
  public void actions() { Sim.stop(); }
};

public void simulateOneRun() {
  SimProcess.init();
  endOfSim.schedule (horizonTime);
  endWarmup.schedule (warmupTime);
  warmupDone = false;
  for (int n = 0; n < nbTaskTypes; n++) {
     new Jobshop.Task (taskType[n]).schedule (ExponentialGen.nextDouble 
        (streamArr, taskType[n].arrivalRate));
  }
  Sim.start();
}

public void printReportOneRun() {
  for (int m=0; m < nbMachTypes; m++) 
     System.out.println (machType[m].report());
  for (int n=0; n < nbTaskTypes; n++) 
     System.out.println (taskType[n].statSojourn.report());
}

static public void main (String[] args) throws IOException { 
  Jobshop shop = new Jobshop();
  shop.simulateOneRun();
  shop.printReportOneRun();
}
}

and here's the output:

 Exception in thread "main" java.io.FileNotFoundException: JobShop.dat (O sistema não conseguiu localizar o ficheiro especificado)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:138)
at java.io.FileInputStream.<init>(FileInputStream.java:97)
at java.io.FileReader.<init>(FileReader.java:58)
at Jobshop.readData(Jobshop.java:31)
at Jobshop.<init>(Jobshop.java:26)
at Jobshop.main(Jobshop.java:133)
Java Result: 1

Any clue on how to fix it?

Thanks in advance.

Answer 1

The way the file is referred, it expects to find the file in the location where you run the application from. It seems like it cannot find it there.

Answer 2

确保相对于当前工作目录（运行java命令的目录）指定.dat文件的路径

Answer 3

您的路径可能是错误的：

input = new BufferedReader (new FileReader ("JobShop.dat"));

Answer 4

As I am using NetBeans IDE to run the project, the file should be added to the Main Project directory inside the NetBeansProjects dir.

As I was creating it inside the source packages, I had to add it's path when opening the file as such:

input = new BufferedReader (new FileReader ("src/JobShop.dat"));