Reading data from a table & parsing it

Question

My code is designed to read the contents of a text file and check if the contents are entered in a format that is as follows:

john : martin : 2 : 1

and if that format is followed then it will output it in the format:

john  [2] | martin [1]

or else it will be counted as an invalid result and the total numbers will not be added to it whereas if the results are in the format then they will get added to the total so with the example it would display the number of vaild results as 1, invalid as 0 and total number as 3.

My question is that my code doesn't work properly as I get this error:

Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:840)
at java.util.Scanner.next(Scanner.java:1461)
at java.util.Scanner.nextInt(Scanner.java:2091)
at java.util.Scanner.nextInt(Scanner.java:2050)
at reader.main(reader.java:33)

So how would I go about fixing this and reading and displaying the data in thee way that I want? Thanks in advance.

import java.io.FileReader;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Locale;
import java.util.Scanner;


public class reader {

    /**
     * @param args
     * @throws FileNotFoundException 
     * @throws FileNotFoundException 
     * @throws FileNotFoundException when the file cannot be loaded 
     */

    public static void main(String[] args) throws FileNotFoundException {

        String hteam;
        String ateam;
        int hscore;
        int ascore;

        Scanner s = new Scanner(new BufferedReader(new FileReader("results2.txt"))).useDelimiter(":");
        // create a scanner which scans from a file and splits at each colon

        while ( s.hasNext() ) { 
            hteam = s.next();       // read the home team from the file
            ateam = s.next();       // read the away team from the file
            hscore = s.nextInt();       //read the home team score from the file
            ascore = s.nextInt();       //read the away team score from the file

            System.out.print(hteam);    // output the line of text to the console
            System.out.print(hscore);
            System.out.print(ateam);
            System.out.println(ascore);
        }
        System.out.println("\nEOF");    // Output and End Of File message.
    }
}

Answer 1

You're looking for s.next() instead of s.nextLine().

hteam = s.nextLine() reads the entire line "john : martin : 2 : 1", leaving nothing left for ateam.

Edit:

As you've said this still isn't working, I'd guess that you have an extra newline at the end of your input file, which is causing s.hasNext() to evaluate to true. This would cause the Scanner to trip up when it's getting the next input line.

Try Scanner s = new Scanner(System.in).useDelimiter("\\s*:\\s*|\\s*\\n\\s*"); to read multiple lines.

See implementation: http://ideone.com/yfiR2S

To verify that a line is in the correct format, I'd (with inspiration from osoblanco's answer) check that there are 4 words and that the last two are integers:

public static boolean verifyFormat(String[] words) {
    // see endnote for isInteger()
    return words.length == 4 && /*isInteger(words[2]) && isInteger(words[3])*/;
}

public static void main(String[] args) throws FileNotFoundException {

    String hteam;
    String ateam;
    int hscore;
    int ascore;
    Scanner s = new Scanner(new BufferedReader(
            new FileReader("results2.txt"))).useDelimiter("\\s*:\\s*|\\s*\\n\\s*");

    while (s.hasNext()) {
        String line = s.nextLine();
        String[] words = line.split("\\s*:\\s*");

        if(verifyFormat(words)) {
            hteam = words[0];       // read the home team
            ateam = words[1];       // read the away team
            hscore = Integer.parseInt(words[2]);       //read the home team score
            ascore = Integer.parseInt(words[3]);       //read the away team score

            System.out.print(hteam);    // output the line of text to the console
            System.out.print(hscore);
            System.out.print(ateam);
            System.out.println(ascore);
        }
    }

    System.out.println("EOF");
}

isInteger() can be found here.

Answer 2

I think scanning isn't quite what you want here. I would just use a BufferedReader and do ReadLine to handle 1 line each time through the for loop.

Then verify each line by the following:

1) String.split(":") and verify 4 pieces.

String [] linePieces = nextLine.split(":");
if(linePieces.length!=4)
{
    //mark invalid, continue loop
}

2) Trim each piece

for(int i =0; i<4; i++)
    linePieces[i] = linePieces[i].trim();

3) Verify piece 3 and piece 4 are numbers, Integer.parseInt with try/catch. In the catch block, count that the line is invalid.

try
{
    name1=linePieces[0];
    name2=linePieces[1];
    score1=Integer.parseInt(linePieces[2]);
    score2=Integer.parseInt(linePieces[3]);
    //count as success and do logic
}catch(NumberFormatException e){
   //invalid line
}