how to assign text in .txt file as a variable value? Java

Question

I wrote this code which takes a .txt file and scans it. Each line represents a separate process with its attributes. I need to be able to loop through each line of the .txt file and assign the different values to the process's fields.

Here's my process class:

public class Process {

    private String name;
    private int arrive_time= 0;
    private int burst_time = 0;
    private int remain_time = 0;

    public Process (String name, int arr_time, int bur_time) {

        this.arrive_time = arr_time;
        this.burst_time = bur_time;
        this.remain_time = burst_time;
        this.name = name;
    }

    public int getArrTime() {return arrive_time;}
    public int getBurTime() {return burst_time;}
    public int getRemTime() {return remain_time;}
    public String getName() {return name;}

    public void decRemTime() {this.remain_time--;}
}

Here's my .txt file:

p1 is supposed to be assigned to the name variable of the first process. 0 is the arrival time. and 8 is the burst time. Then we move onto the next line and do the same for a new process that we will be creating every time I move to a new line in the .txt

Here's my code for assigning things:

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.*;

public class Test {

    public static void main(String[] args) {

        //Priority queue for storing the initialized processes
        PriorityQueue<Process> prq = new PriorityQueue<Process>(5, new Comparator<Process> () {

            @Override
            public int compare(Process p1, Process p2) {
                return p1.getArrTime() - p2.getArrTime();
            }
        });

        BufferedReader br = null;
        String line;

        try {
            br =  new BufferedReader(new FileReader("C:\\Users\\Veni\\Desktop\\test\\test.txt\\"));
        }
        catch (FileNotFoundException fnfex) {
            System.out.println(fnfex.getMessage() + "File not found");
            System.exit(0);
        }

        try {
            int localProcessIndex = 0;

            /* Count number of lines in .txt and store number in localProcessIndex.
             * Then declare exactly that many processes.
             * 
             * Then move to the loop below and start reading each line's values
             * and start initialising the processes with those values.
             * 
             * Then move all the processes to the prq priority queue.
            */

            while((line = br.readLine()) != null) {


                //Process localProcessIndex = new Process(line.split);
                //System.out.println(line);
            }
        }
        catch(IOException ioex) {
            System.out.println(ioex.getMessage() + "Error reading");
        }

        SPN spn = new SPN(prq);
        spn.SPN_ALG();
    }
}

npinti · Accepted Answer · 2015-04-13 10:10:24Z

1

Assuming that your file will always have that same structure, you could use the split(String regex) method to process your data:

while((line = br.readLine()) != null) {
    try {
    String[] params = line.split(" ");
    prq.add(new Process(params[0], Integer.parseInt(params[1]), Integer.parseInt(params[2]))),
    ...
    }
    catch(Exception e) {
        //Log
    }
}

EDIT: What you need to do is to have a list of Process items. This will allow you to create the amount of processes you need and make them available at a later stage. I have modified the code above to provide this functionality.

edited Apr 13, 2015 at 10:10

answered Apr 13, 2015 at 9:51

npinti

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5 Comments

Rumen Hristov Over a year ago

Excellent. Now I need to figure out how I can generate the exact number of processes as there are lines. And do that automatically. If it helps, I wrote exactly what my problem is in the last code snippet - in comments.

npinti Over a year ago

@RumenHristov: I have updated my answer. Please try to use collections for these sort of scenarios, as opposed to creating a new item manually.

Rumen Hristov Over a year ago

that's exactly what I did. Here:prq.add(new Process(params[0], Integer.parseInt(params[1]), Integer.parseInt(params[2])));

npinti Over a year ago

@RumenHristov: Yes sorry my bad. Should be fixed now.

Rumen Hristov Over a year ago

Nice job. Thanks very much. Love this place! :) :)

Moishe Lipsker · Accepted Answer · 2015-04-13 13:42:24Z

1

For each line, split it by a space. Next use parseInt to get the numbers. Finally call the constructor with these values:

String line = "P1 0 8";
String params = line.split("\s");
Process process = new  Process(params[0], Integer.parseInt(params[1]), Integer.parseInt(params[2]));

edited Apr 13, 2015 at 13:42

answered Apr 13, 2015 at 9:52

Moishe Lipsker

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