Java. Problems reading an input

Question

I am doing a homework assignment that deals with classes and objects. In it, I have an Address class, Letter class, and PostOffice class that when calling PostOffice, takes an input file and scans through it, printing basically everything in the input file the way it should appear on a letter (to: bla, from: bla, postage amount, to and from address, etc.)

i get an error that reads:

Exception in thread "main" java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Scanner.java:1516)
at PostOffice.readLetters(PostOffice.java:33)
at PostOffice.main(PostOffice.java:14)

and I dont really understand why....

here is my post office class:

import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

public class PostOffice {

private final int MAX = 1000;
private Letter [] letterArray = new Letter[MAX];
private int count;

public static void main(String [] args) {
    PostOffice postOffice = new PostOffice();
    postOffice.readLetters("letters.in");
    postOffice.sortLetters();
    postOffice.printLetters();
}

public PostOffice() {
    Letter [] myLetters = letterArray;
    this.count = 0;
}

public void readLetters(String filename) {
    String toName, toStreet, toCity, toState, toZip;
    String fromName, fromStreet, fromCity, fromState, fromZip, temp; //, weight;
    double weight;
    int index;
    Scanner s = new Scanner(filename);
    if (s != null) {
        while(s.hasNext()){
            toName = s.nextLine();
            toStreet = s.nextLine();
            temp = s.nextLine();
            index = temp.indexOf(",");
            toCity = temp.substring (0, index);
            index = index + 2;
            toState = temp.substring (index, index + 2);
            toZip = temp.substring (index);
            fromName = s.nextLine();
            fromStreet = s.nextLine();
            temp = s.nextLine();
            index = temp.indexOf(",");
            fromCity = temp.substring (0, index);
            index = index + 2;
            fromState = temp.substring (index, index + 2);
            fromZip = temp.substring (index);
            String var = s.nextLine();
            weight = Double.parseDouble(var);
            //weight = s.nextLine();
            Letter l = new Letter(toName, toStreet, toCity, toState, toZip, fromName, fromStreet, fromCity, fromState, fromZip, weight);
            this.count += 1;
            this.letterArray[count - 1] = l;
        }
    }
    s.close();
}

public static void sortLetters() {
//call sortSearchUtil This method should call the compareTo method provided by the Letter class to sort.  
//You may use any sorting routine you wish (see SortSearchUtil.java)
}

public static void printLetters() {
//call tostring of letter class. print the count of Letters followed by the total postage followed 
//by each Letter (make sure you use the toString method provided by the Address and Letter classes for this)
}

}

my letter class:

    public class Letter extends PostOffice implements Comparable<Letter> {
private static final double POSTAGE_RATE = 0.46;
private String fromName;
private Address fromAddr;
private String toName;
private Address toAddr;
private double weight;


    public Letter (String fromName, String fromStreet, String fromCity, String fromState,       String fromZip, String toName, 
String toStreet, String toCity, String toState, String toZip, double weight) {
this.fromName = fromName;
this.fromAddr = new Address(fromStreet, fromCity, fromState, fromZip);
this.toName = toName;
this.toAddr = new Address(toStreet, toCity, toState, toZip);
this.weight = weight;   
}

public String toString() {
String result;
result = String.format("from: %s\t\t\t%5.2f\n%s", fromName, getPostage(weight), fromAddr);
result = result + String.format("\t\t To: %s\n\t\t%s", toName, toAddr);
return result;
}

    public int compareTo(Letter that) {
int value;
value = this.toAddr.getZip().compareTo(that.toAddr.getZip());
return value;
}


public static double getPostage(double weight) {
double workWeight;
workWeight = weight + 0.999;
workWeight = (int)workWeight;   
return workWeight * POSTAGE_RATE;
    } 
}

and my address class:

import java.awt.*;
import java.util.*;

public class Address {
private String street;
private String city;
private String state;
private String zip;

    public Address (String street, String city, String state, String zip) {
    this.street = street;
    this.city = city;
    this.state = state;
    this.zip = zip;
    }

    public String getStreet() {
    return street;
    }

    public void setStreet(String street) {
    this.street = street;
    }

    public String getCity() {
    return city;
    }

    public void setCity(String city) {
    this.city = city;
    }

    public String getState() {
    return state;
    }

    public void setState(String state) {
    this.state = state;
    }

    public String getZip() {
    return zip;
    }

    public void setZip(String zip) {
    this.zip = zip;
    }

    public String toString() {
    String result;
    result = String.format("%s\n%s, %s %s", street, city, state, zip);
    return result;  
    }
}

and this is the content of the text file

Stu Steiner (NEW LINE)
123 Slacker Lane (NEW LINE)
Slackerville, IL  09035 (NEW LINE)
Tom Capaul(NEW LINE)
999 Computer Nerd Court (NEW LINE)
Dweebsville, NC  28804-1359 (NEW LINE)
0.50 (NEW LINE)
Tom Capaul (NEW LINE)
999 Computer Nerd Court (NEW LINE)
Dweebsville, NC  28804-1359 (NEW LINE)
Chris Peters (NEW LINE)
123 Some St. (NEW LINE)
Anytown, CA  92111-0389 (NEW LINE)
1.55 (NEW LINE)

Everything compiles, I just need it to output like this:

----------------------------------------------------------------------------

From: From value                                              Postage value
From Address value (be sure and use Address toString)

                    To: To value
                    To Address value (be sure and use Address toString)

----------------------------------------------------------------------------

Your problem isn't clear from your question statement. Is any output being generated at all? Or is it that there is output being generated but it is the wrong output? — Jim Kiley
– Jim Kiley, Commented Jan 17, 2012 at 20:11
no output at all. it gives me an error in postoffice main saying: Exception in thread "main" java.util.NoSuchElementException: No line found at java.util.Scanner.nextLine(Scanner.java:1516) at PostOffice.readLetters(PostOffice.java:33) at PostOffice.main(PostOffice.java:14) — anthony
– anthony, Commented Jan 17, 2012 at 20:12
it would be helpful if you could edit your original question to include the error code as well as a well formed example of an input file (couple of lines will be enough). — tim
– tim, Commented Jan 17, 2012 at 20:34
@anthony Can you please accept the answer which solved your problem? — Adel Boutros
– Adel Boutros, Commented Apr 19, 2013 at 8:22

Adel Boutros · Accepted Answer · 2012-01-17 22:50:12Z

4

You do s.readline() many times inside 1 iteration of while loop. This is why you're getting the error.

You need to call readLine() only once inside your while loop

Example in your code:

while(s.hasNext()){
        toName = s.nextLine();
        toStreet = s.nextLine();
        temp = s.nextLine();
        // ...
    }

These are 3 calls to nextLine, how are you sure there are still lines?

SOLUTION:

put an if statement before every s.nextLine() except the first one. Example:

while(s.hasNext()){
     toName = s.nextLine();
     if (s.hasNext()) {
         toStreet = s.nextLine();
     }
     if (s.hasNext()) {
         temp = s.nextLine();
     }
     // ...
}

edited Jan 17, 2012 at 22:50

answered Jan 17, 2012 at 20:17

Adel Boutros

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4 Comments

anthony Over a year ago

yea i know its bad, im somewhat new to this. but were given a text file that reads as follows: Stu Steiner 123 Slacker Lane Slackerville, IL 09035 Tom Capaul 999 Computer Nerd Court Dweebsville, NC 28804-1359 0.50 Tom Capaul 999 Computer Nerd Court Dweebsville, NC 28804-1359 Chris Peters 123 Some St. Anytown, CA 92111-0389 1.55 so i am expecting that there is a next line. sorry I dont know how to properly comment this but there are 14 lines of code

Jim Kiley Over a year ago

Adel Boutros, the comment "your program is sooo bad" in your answer is not helpful or appropriate.

anthony Over a year ago

guys I understand that the .nextLine is causing problems because there is no next line, but that is because the scanner is reading the word letters.in rather then scanning the file and checking whether that file has next line. thats what Im having trouble with. i debugged and made it to the toStreet = s.nextLine(); and it just fails. if you guys could figure out an alternative for me or help me with suggestions as to how I can properly scan this text file, i would appreciate it greatly :)

Adel Boutros Over a year ago

@anthony but care, this is not the optimal solution as some of the variables might become null if s.hasNext() returns false.

user800014 · Accepted Answer · 2012-01-17 20:16:21Z

2

Probably you missed to test if you have the next line:

http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Scanner.html#hasNext%28%29

answered Jan 17, 2012 at 20:16

user800014

1 Comment

anthony Over a year ago

i dont think the problem is that there isnt a next line, the problem is when i think the scanner isnt getting the desired file. in the array it has the word scanner.in rather then the file I want. thats what I need help with.

tim · Accepted Answer · 2012-01-17 20:57:59Z

Your suspicion was right: you are not opening up a file but just passing the string "letter.in" to the scanner. The correct code would be:

    Scanner s = null;
    try {
        s = new Scanner(new File(filename));
    } catch (FileNotFoundException ex) {
        Logger.getLogger(PostOffice.class.getName()).log(Level.SEVERE, null, ex);
    }
    if (s != null) {
         ....
    }

Your program still will not print anything as the printLetters() method is not implemented, but it will not crash anymore (at least not if the file always has a multiple of 7 lines). The input format is not very well chosen, but as it is homework I guess it was not really your choice. to make the code at least a little bit less error prone you could ask before every nextLine if there actually is a next line (this is not a good solution, but one that is done without much work).

Bhesh Gurung · Accepted Answer · 2012-01-17 21:10:18Z

0

The problem is the mistmatch (hasNext() and nextLine()).

With nextLine() you should use hasNextLine(). This is probably the combination you need as you seem to read it line by line.

e.g. looking at your text file something as follows should but modification must be made in case if the text file is not always well formed:

while(s.hasNextLine()) { // check if there is next line
    String toName = s.nextLine();
    String toAddrLine1 = s.nextLine();
    String toAddrLine2 = s.nextLine();
    String fromName = s.nextLine();
    String fromAddrLine1 = s.nextLine();
    String fromAddrLine2 = s.nextLine();
    String postageValueStr = s.nextLine();

    //do further processing down here

While hasNext() should be used in combination with next().

Please, go through the Scanner doc.

edited Jan 17, 2012 at 21:10

answered Jan 17, 2012 at 20:53

Bhesh Gurung

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