CODEWITHSUNDEEP
javaexceptionjava.util.scanner
user2271029
user2271029

Reputation: 13

Error using scanner class for reading .txt

i am working on a program to read a binary file and update it form a txt file, it was working the all of a sudden it started throwing this error

Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Scanner.java:907)
    at java.util.Scanner.next(Scanner.java:1416)
    at StockManage.updateInv(StockManage.java:134)
    at StockManage.main(StockManage.java:173)

heres the code thats causes the error

try
{
    Scanner trans = new Scanner(new File(file));
    RandomAccessFile inv = new RandomAccessFile (file2,"rws");
    String tempName = "Temp" + (int)(Math.random()*1000000) + ".dat";
    RandomAccessFile newInv = new RandomAccessFile (tempName , "rws");
    File newFile = new File(tempName);

    String transISBN = trans.next();
    String author = inv.readUTF();
    String title = inv.readUTF();
    String iSBN = inv.readUTF();
    int amount = inv.readInt();

    while (inv.getFilePointer()<=inv.length())
    {
        boolean empty = true;

        while (empty&&trans.hasNext())
        {

            if (iSBN.compareTo(transISBN)<0)
            {
                empty = false;
                break;
            }
            else if (iSBN.compareTo(transISBN)==0)
            {
                int change = trans.nextInt();
                amount += change;
                transISBN = trans.next();
            }
        }

        newInv.writeUTF(author);
        newInv.writeUTF(title);
        newInv.writeUTF(iSBN);
        newInv.writeInt(amount);

        author = inv.readUTF();
        title = inv.readUTF();
        iSBN = inv.readUTF();
        amount = inv.readInt();


    }

im really stuck in this one so any help would be great

Upvotes: 0

Views: 101

Answers (2)

İsmet Alkan
İsmet Alkan

Reputation: 5447

This code part is error-prone:

else if (iSBN.compareTo(transISBN)==0)
{
    int change = trans.nextInt();
    amount += change;
    transISBN = trans.next();
}

You control trans.hasNext() in the while loop, but you don't before transISBN = trans.next(); put an if(trans.hasNext()) at the top of it and problem will be solved, I guess.

Upvotes: 0

pauljwilliams
pauljwilliams

Reputation: 19225

Before calling next() on a Scanner object you should call hasNext() to check if there is actually more data to read.

Upvotes: 2

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