Thread: Scanner closed error

What would be the problem with this code?

import java.io.*;
import java.util.Scanner; 
 
/**
 * Write a description of class capital here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class capital
{public static void main(String[] args) throws FileNotFoundException
    {
        // ask the user for the search string
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Please enter part of the country name: ");
        String searchString = keyboard.next().trim().toLowerCase();
 
        // open the data file
        File countryFile = new File("CountryData.csv");
 
        // create a scanner from the file
        Scanner countryInput = new Scanner(countryFile);
 
        // set up the scanner to use "," as the delimiter
        countryInput.useDelimiter("[\\r,]");
 
        // read one line of data at a time, processing each line
        while(countryInput.hasNext())
        {
            // read the 3 parts of the line
 
            // first the country and capital
            String country = countryInput.next();
            String capital = countryInput.next(); 
 
            // then the population info
            int population = countryInput.nextInt();
 
            // print out the info if the country name contains the input search string
            if(country.toLowerCase().contains(searchString))
            {
                System.out.println(country + "\t" +
                    capital + "\t" + population);
            }
            // be polite and close the file
            countryInput.close();
        }
    }
}

where I get this error:
java.lang.IllegalStateException: Scanner closed
at java.util.Scanner.ensureOpen(Scanner.java:1115)
at java.util.Scanner.hasNext(Scanner.java:1379)
at capital.main(capital.java:28)

It doesnt seem to read the file, which was working before.
And would anyone tell me how I can get a message to appear if there is no match from the file? If I use an else statement, the message appears on every line, causing the same message to appear 5 times.

Basically the program is meant to read the file, user inputs part of the name, it shows user the information. If it cannot find it, it needs to show a helpful message.

--- Update ---

I really need help. Its due tomorrow, this is really stressful.

Hi

You need to put the statement countryInput.close(); i.e close the scanner after the while loop.
And for displaying the message define a variable found before the while loop as int found = 0;
increment it i.e found++ in the if condition.
and outside the while loop i.e after putting countryInput.close() put the below condition
if (found==0)
{
System.out.println("The File does not contain the input string");
}
hope this solves your problem.

Sorry, I had the original file and now all i need is how to get a message displayed when there is no match in the file. I put something like this as a test:

 if(country.toLowerCase().contains(searchString))
            {
                System.out.println(country + "\t" +
                    capital + "\t" + population);
            }
            else
            {
                System.out.print("test");
            }

and it resulted in this:
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test
test

This would indicate it is going through the file and trying to find the phrase, then returning test with each line that doesnt have the phrase.
So how can I get this to occur once?

Hi

You can define a counter variable "found" before the while loop as int found = 0;
increment it i.e found++ in the if condition.
and outside the while loop put the below condition
if (found==0)
{
System.out.println("The File does not contain the input string");
}

How would this look in my code above?
Because I have tried and it doesnt work. I might be doing something wrong.

hi

have appended the wid your code below

public class capital
{public static void main(String[] args) throws FileNotFoundException
{
// ask the user for the search string
Scanner keyboard = new Scanner(System.in);

System.out.print("Please enter part of the country name: ");
String searchString = keyboard.next().trim().toLowerCase();

// open the data file
File countryFile = new File("D:/Nut SMS/Project/SMSApplicationService/src/CountryData.csv");

// create a scanner from the file
Scanner countryInput = new Scanner(countryFile);

// set up the scanner to use "," as the delimiter
countryInput.useDelimiter("[\\r,]");

// read one line of data at a time, processing each line
int found = 0;
while(countryInput.hasNext())
{
// read the 3 parts of the line

// first the country and capital
String country = countryInput.next();
String capital = countryInput.next();

// then the population info
int population = countryInput.nextInt();

// print out the info if the country name contains the input search string
if(country.toLowerCase().contains(searchString))
{
System.out.println(country + "\t" +
capital + "\t" + population);
found ++;

}


// be polite and close the file


}
if (found==0)
{
System.out.println("The File does not contain the input string");
}
countryInput.close();
}
}

Thankyou so much! Now I see what I did wrong xD
The code works as it should