Implementing comparable java - java

I am trying to sort a list of user entered tasks and dates by date using comparable interface. I have the tasks in a external .txt file and am a little confused if I am accessing the correct variables. The program compiles, but when I try to sort the tasks, it seems to erase the contents of the file. Here is what I have:
public class DueDate implements Comparable<DueDate>{
public String addedTask = "";
public String enteredDueDate;
public DueDate(String addedTask, String dueDate){
this.addedTask = addedTask;
this.enteredDueDate = enteredDueDate;
}
public String toString(){
return addedTask+"\t"+enteredDueDate+"\t";
}
#Override
public int compareTo(DueDate o) {
return this.enteredDueDate.compareTo(o.enteredDueDate);
}
}
public class Main {
public static String fileName = "/Users/eringray/Desktop/tasklistjava/src/javatask.txt";
public static void main(String[] args) throws IOException {
int menuItem = -1;
while(menuItem != 0){
menuItem = menu();
switch (menuItem){
case 1:
showTaskList();
break;
case 2:
addTask();
break;
case 3:
sortList();
case 4:
deleteTasks();
break;
case 0:
break;
default:
System.out.println("Invalid Input");
}
}
}
static int menu(){
int choice;
Scanner sc = new Scanner(System.in);
System.out.println("\n Task List Menu \n");
System.out.println("0: Exit Menu");
System.out.println("1: Show Tasks in List");
System.out.println("2: Add Task to List");
System.out.println("3: Sort Tasks by Due Date");
System.out.println("4: Delete Tasks");
System.out.println();
System.out.println("Enter a choice: ");
choice = sc.nextInt();
return choice;
}
static void showTaskList(){
System.out.println("\nTask List\n");
try {
Scanner inFile = new Scanner(new FileReader(fileName));
String line;
int number = 1;
while(inFile.hasNextLine()){
line = inFile.nextLine();
System.out.println(number + ". " + line);
++number;
}
System.out.println();
inFile.close();
} catch (FileNotFoundException ioe) {
System.out.println(ioe);
}
}
static void addTask(){
System.out.println("\nAdd Task\n");
try {
Scanner input = new Scanner(System.in);
PrintWriter outFile = new PrintWriter(new FileWriter(fileName, true));
System.out.println("Enter a Task: ");
String addedTask = input.nextLine();
System.out.println("Set Due Date for this Task(yyyy-mm-dd): ");
String dueDate = input.nextLine();
outFile.println(addedTask + "\t" + dueDate);
outFile.close();
} catch (IOException ioe) {
System.out.println(ioe);
}
}
static void sortList() throws IOException {
System.out.println("\nSorted List\n");
try {
BufferedReader br = new BufferedReader(new FileReader(fileName));
BufferedWriter bw = new BufferedWriter(new FileWriter(fileName, true));
ArrayList<DueDate> tasks = new ArrayList<DueDate>();
String line = "";
while((line = br.readLine()) != null) {
String[] values = line.split("\t");
if(values.length == 2) {
String addedTask = values[0];
String enteredDueDate = values[1];
DueDate d = new DueDate(addedTask, enteredDueDate);
tasks.add(d);
}
}
Collections.sort(tasks);
for(int i = 0; i < tasks.size(); i++){
DueDate date = tasks.get(i);
String lineText = date.toString();
bw.write(lineText);
bw.newLine();
}
br.close();
bw.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
private static void deleteTasks(){
PrintWriter writer = null;
try {
writer = new PrintWriter(fileName);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
assert writer != null;
writer.print("");
writer.close();
}
}
Sorry for the extra code, but thought it might help you see what I'm trying to do. Any suggestions would be great. I am new to Java, so please be patient with me! Thanks!

The problem is a missing break statement in your switch which is calling the deleteTasks() method after calling sortList(). Change your code to this and it should work fine:
int menuItem = -1;
while(menuItem != 0){
menuItem = menu();
switch (menuItem){
case 1:
showTaskList();
break;
case 2:
addTask();
break;
case 3:
sortList();
break; //The missing break
case 4:
deleteTasks();
break;
case 0:
break;
default:
System.out.println("Invalid Input");
}
}
And the constructor of the DueDate class is missing the assignment of the enteredDueDate variable since the parameter was named dueDate and not enteredDueDate. You should change it to something like this:
public DueDate(String addedTask, String enteredDueDate){
this.addedTask = addedTask;
this.enteredDueDate = enteredDueDate;
}
since you are currently assigning the member variable to it's own value.
You should also consider changing the sortList method, especially the BufferedWriter or it will duplicate the list each time you call it. Something like this sould do it:
BufferedReader br = new BufferedReader(new FileReader(fileName));
ArrayList<DueDate> tasks = new ArrayList<DueDate>();
String line = "";
while((line = br.readLine()) != null) {
String[] values = line.split("\t");
if(values.length == 2) {
String addedTask = values[0];
String enteredDueDate = values[1];
DueDate d = new DueDate(addedTask, enteredDueDate);
tasks.add(d);
}
}
Collections.sort(tasks);
br.close();
//Changed it to not append but overwrite the old file so it only contains the sorted list
BufferedWriter bw = new BufferedWriter(new FileWriter(fileName, false));
for (DueDate date : tasks) {
String lineText = date.toString();
bw.write(lineText);
bw.newLine();
}
bw.flush();
bw.close();
EDIT:To print the sorted list out there are a few things you could do.
The easiest way would probably be to append a call of the showTaskList method to the end of the sortList method like this
//...
bw.flush();
bw.close();
showTaskList();
} catch (FileNotFoundE
e.printStackTrace(
}
or you could loop through the ArrayList and print them out like this:
//...
bw.flush();
bw.close();
for (int i = 0; i < tasks.size(); i++) {
DueDate dueDate = tasks.get(i);
System.out.println(i+". "+dueDate.toString());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
EDIT 2: The easiest way to get all Tasks with empty DueDate to the bottom when sorting is to change the compareTo method in DueDate class:
#Override
public int compareTo(DueDate o) {
return -this.enteredDueDate.compareTo(o.enteredDueDate);
}
Just negate it so all entries are sorted descending and those with empty DueDate will be at the end of the list (it relays on how strings are compared by default).
But if you want to use Tasks with no due date you'll run into a problem in your sortList method since the split("\t")method will only return an array with length 1 and your if condition would fail. One way to solve it looks like this:
//...
while ((line = br.readLine()) != null) {
String[] values = line.split("\t");
//To ensure it's still valid data
if (values.length >= 1 && values.length <= 2) {
String addedTask = values[0];
String enteredDueDate;
//Check whether dueDate has a value or is empty
if (values.length == 1)
enteredDueDate = "";
else
enteredDueDate = values[1];
DueDate d = new DueDate(addedTask, enteredDueDate);
tasks.add(d);
}
}
//...
or more compact version (does exactly the same thing)
//...
while ((line = br.readLine()) != null) {
String[] values = line.split("\t");
if (values.length >= 1 && values.length <= 2)
tasks.add(new DueDate(values[0], values.length == 1 ? "" : values[1]));
}
//...
Hope this helps (:

Related

How to create a numbered list

I want to create a numbered list, where it shows the index number beside each line. I'm not too sure how to achieve this.
This is the code where i create my list:
public void readFile(Scanner in)
{
inputStudentID = null;
inputMark = 0;
try
{
File file = new File("Marks.txt");
in = new Scanner(file);
}
catch (FileNotFoundException e)
{
System.out.println(e.getMessage());
System.out.println("in " + System.getProperty("user.dir"));
System.exit(1);
}
while (in.hasNextLine())
{
String studentRecord = in.nextLine();
List<String> values = Arrays.asList(studentRecord.split(","));
String inputStudentID = values.get(0);
String sInputMark;
sInputMark = values.get(1);
int inputMark = Integer.parseInt(sInputMark);
addStudent(inputStudentID, inputMark);
}
in.close();
}

Comparing integers from a text file and program that has strings involved

I've tried in vain to compare scores in my application with scores already saved in a separate text file. Comparing the score is easy enough when strings aren't involved but when I save the score and assign it a name, the program doesn't work as it cannot parse strings & integers.
Example text file:
Name, 8
Name, 1
Name, 4
Code I'm using to compare:
int highScore = 0;
try {
BufferedReader reader = new BufferedReader(new FileReader("txt.txt"));
String line = reader.readLine();
while (line != null)
{
try {
int score = Integer.parseInt(line.trim());
if (score > highScore)
{
highScore = score;
}
} catch (NumberFormatException e1) {
//ignore invalid scores
//System.err.println("ignoring invalid score: " + line);
}
line = reader.readLine();
}
reader.close();
} catch (IOException ex) {
System.err.println("ERROR");
}
The rest of the code is fine and the score is generated as the game finishes comparing it to the score in the file, it just generates a 0 value when comparing as it reads the string and doesn't work. I'm not sure on how to use scanners/delimiters.
EDIT:
I'd like the program to execute and show the name of the user which got that highscore. So the desired output would be;
The all time high score was 8 by Name1
Currently it only says the highscore (following Michu93's input).
Run the below program. It will give you desired output. Please correct the other things, I just concentrated on output.
public class Test {
static int highScore = 0;
static String highscorer = "";
public static void main(String[] args) {
try {
BufferedReader reader = new BufferedReader(new FileReader("src/com/test/package1/txt.txt"));
String line = null;
while ((line = reader.readLine()) != null) {
try {
String[] parts = line.split(",");
int tempScore = Integer.parseInt(parts[1].trim());
String tempHigScorer = (parts[0]);
if (tempScore > highScore) {
highScore = tempScore;
highscorer = tempHigScorer;
}
} catch (NumberFormatException e1) {
// handle NumberFormatException if any
}
}
reader.close();
} catch (IOException ex) {
System.err.println("ERROR");
}
System.out.println("The all time high score was " + highScore + " by name " + highscorer);
}
}
Remove digits from string and parse it to int:
int score = Integer.valueOf(line.replaceAll("[^\\d.]", ""));
#Edit
int highScore = 0;
String name = "";
try {
BufferedReader reader = new BufferedReader(new FileReader("txt.txt"));
String line = reader.readLine();
while (line != null) {
try {
int score = Integer.parseInt(line.split(" ")[1]);
if (score > highScore) {
highScore = score;
name = line.split(" ")[0].replace(",", "");
}
} catch (NumberFormatException e1) {
//ignore invalid scores
//System.err.println("ignoring invalid score: " + line);
}
line = reader.readLine();
}
System.out.println(String.format("The all time high score was %s by %s", highscore, name));
} catch (IOException ex) {
System.err.println("ERROR");
} finally {
reader.close(); // close stream always in finnaly block or use try with resources!!!
}
Observe that when you read a whole line you are getting a String with both Name and the Integer you want to get. I'd do the following:
int highScore = 0;
String name = "";
try {
BufferedReader reader = new BufferedReader(new FileReader("txt.txt"));
String line = null;
while ((line = reader.readLine()) != null) {
try {
String[] parts = line.split(",");
if(parts.length > 1){
int score = Integer.parseInt(parts[1].trim());
if (score > highScore) {
highScore = score;
name = line[0];
}
}
} catch (NumberFormatException e1) {
//ignore invalid scores
//System.err.println("ignoring invalid score: " + line);
}
}
System.out.println("The all time high score was %s by %s", highScore, name);
reader.close();

Press any key with BufferedReader

I created a java file called Product.java. I also created a text file called Items.txt. Basically when the user enter the word using sequential search to search the data what they are looking from Items.txt. My main problem is when I enter 3 to display all the records or enter x to exit the program, it keeps on looping. But I don't how to resolve this problem. Can anyone solved this for me?
Items.txt
1000|Cream of Wheat|Normal Size|Breakfast|NTUC|5|3.00
1001|Ayam Brand|Small Size|Canned|NTUC|4|4.00
Product.java
import java.io.*;
import java.util.*;
public class Product {
public static void main(String[] args) {
ArrayList<Item> prdct = new ArrayList<Item>();
String inFile = "items.txt";
String line = "";
FileReader fr = null;
BufferedReader br = null;
StringTokenizer tokenizer;
int quantity;
String id, brandname, desc, category, supplier;
float price;
try{
fr = new FileReader(inFile);
br = new BufferedReader(fr);
line = br.readLine();
while(line!=null)
{
tokenizer = new StringTokenizer(line,"|");
id = tokenizer.nextToken();
brandname = tokenizer.nextToken();
desc = tokenizer.nextToken();
category = tokenizer.nextToken();
supplier = tokenizer.nextToken();
quantity = Integer.parseInt(tokenizer.nextToken());
price = Float.parseFloat(tokenizer.nextToken());
Item itm = new Item(id,brandname,desc,category,supplier,quantity,price);
prdct.add(itm);
line = br.readLine();
}
br.close();
}
catch(FileNotFoundException e){
System.out.println("The file " + inFile + " was not found.");
}
catch(IOException e){
System.out.println("Reading error!");
}
finally
{
if (fr!=null){
try
{
fr.close();
}
catch(IOException e)
{
System.out.println("Error closing file!");
}
}
}
String INPUT_PROMPT = "\nPlease enter 3 to display all records, 4 to insert record, 5 to remove old records " + "or enter 'x' to quit.";
System.out.println(INPUT_PROMPT);
try
{
BufferedReader reader = new BufferedReader
(new InputStreamReader (System.in));
line = reader.readLine();
while(reader != null)
{
for(int i=0; i<prdct.size(); i++)
{
if(prdct.get(i).id.contains(line) || prdct.get(i).brandname.contains(line) || prdct.get(i).desc.contains(line)
|| prdct.get(i).category.contains(line) || prdct.get(i).supplier.contains(line))
{
System.out.println(prdct.get(i));
}
System.out.println(INPUT_PROMPT);
line = reader.readLine();
}
}
while("3".equals(line))
{
for(int i=0; i<prdct.size(); i++)
{
System.out.println(prdct.get(i));
}
System.out.println(INPUT_PROMPT);
line = reader.readLine();
}
while(!line.equals("x"))
{
System.out.println(INPUT_PROMPT);
line=reader.readLine();
}
}
catch(Exception e){
System.out.println("Input Error!");
}
}
}
The problem is with this loop:
while(reader != null)
{
for(int i=0; i<prdct.size(); i++)
{
if(prdct.get(i).id.contains(line) || prdct.get(i).brandname.contains(line) || prdct.get(i).desc.contains(line)
|| prdct.get(i).category.contains(line) || prdct.get(i).supplier.contains(line))
{
System.out.println(prdct.get(i));
}
System.out.println(INPUT_PROMPT);
line = reader.readLine();
}
}
It keeps on looping while reader is not null and it will never be. You might want to try checking something else that suits your problem better, maybe:
While(!line.equals("3"))
While(!line.equals("x"))
While(line != null)
Otherwise, even if there is an 'x', '3' or simply nothing, still (reader != null) and therefore the loop is infinite.
I suspect that the newline character is what causes the comparison to fail.
Instead of checking if:
"3".equals(line)
Try:
"3".equals(line.trim())
Same applies to the following comparison.
Try changing this..
line = reader.readLine();
while(reader != null)
{
to this..
line = reader.readLine();
while(line != null)
{
You are looping on the reader being not null, which it always will be.
you have to define these functions:
public void showAllRecords() {
// show all record here
}
public void insertRecord() {
// insert record here
}
public void removeRecord() {
// insert record here
}
public void exit() {
// insert record here
}
then
do{
System.out.println(INPUT_PROMPT);
switch(line)
{
case "3":
showAllRecords();
break;
case "4":
insertRecord();
break;
case "5":
removeRecord();
}
}while(!line.equals('x'));

Java NoSuchElementException for Scanner in while loop [duplicate]

This question already has an answer here:
How to use java.util.Scanner to correctly read user input from System.in and act on it?
(1 answer)
Closed 7 years ago.
EDIT: While this issue has been marked as a duplicate, the other issue is different to my situation; it seems as though the program is ignoring this line:
decision = scan.nextInt();
I'm having some trouble with my scanner. I have a program that runs off a simple menu system.
The program works, but whenever it goes back to repeating the program again (I made the program have the ability to repeat by putting it in a while loop) it throws this error:
Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Scanner.java:919)
at java.util.Scanner.next(Scanner.java:1542)
at java.util.Scanner.nextInt(Scanner.java:2172)
at java.util.Scanner.nextInt(Scanner.java:2131)
at GuardSearch.Menu(GuardSearch.java:29)
at GuardSearch.main(GuardSearch.java:8)
The program all works on the first run through the menu and its actions, but then when the call of the if statement is completed and the program returns to the while loop, it throws this exception. What am I missing?
I can post all the classes of the program if needed, however I believe my problem is within the following class:
import java.util.Scanner;
import java.lang.*;
public class GuardSearch {
public static void main(String[] args) {
Menu();
}
public static void Menu(){
Scanner scan = new Scanner(System.in);
boolean leave = false;
while(leave!=true){
final String ANSI_CLS = "\u001b[2J";
final String ANSI_HOME = "\u001b[H";
System.out.print(ANSI_CLS + ANSI_HOME);
System.out.flush();
int decision = 0;
System.out.println("Welcome to GuardSearch, our little slice of Google.\n");
while ((decision != 1) || (decision != 2)){
System.out.println("Please enter the number of what you would like to do from the following list:");
System.out.println("1. Submit knowledge.");
System.out.println("2. Search.");
System.out.println("3. Quit.");
decision = scan.nextInt();
if (decision == 1) {
Submit submit = new Submit();
submit.takeinfo();
break;
}
else if (decision == 2){
Search search = new Search();
search.takekeywords();
break;
}
else if (decision == 3){
leave = true;
break;
}
}
}
scan.close();
}
}
Thanks in advance. I have researched this issue and found no occurrences relevant to my exact issue.
EDIT: Here is my Submit and Search class as requested:
import java.io.*;
import java.util.Scanner;
public class Submit {
public static void takeinfo() {
final String ANSI_CLS = "\u001b[2J";
final String ANSI_HOME = "\u001b[H";
System.out.print(ANSI_CLS + ANSI_HOME);
System.out.flush();
System.out.println("Submit your knowledge to the system.\n");
Scanner sc = new Scanner(System.in);
int decision = 0;
while ((decision != 1) || (decision != 2)){
System.out.println("1. Change an existing article.");
System.out.println("2. Create a new article.");
System.out.println("3. Delete an article.");
System.out.println("4. Back.");
decision = sc.nextInt();
if (decision == 1) {
ChangeArticle chngArt = new ChangeArticle();
chngArt.takeinfo();
break;
}
else if (decision == 2){
CreateArticle createArt = new CreateArticle();
createArt.title();
break;
}
else if (decision == 3){
DeleteArticle deleteArt = new DeleteArticle();
deleteArt.takeinfo();
break;
}
else if (decision == 4){
GuardSearch gs = new GuardSearch();
gs.Menu();
break;
}
else {
System.out.println("Please enter a valid number.\n");
}
}
sc.close();
}
}
And the Search class:
import java.util.*;
import java.io.*;
public class Search {
Scanner sc = new Scanner(System.in);
public void takekeywords() {
final String ANSI_CLS = "\u001b[2J";
final String ANSI_HOME = "\u001b[H";
System.out.print(ANSI_CLS + ANSI_HOME);
System.out.flush();
System.out.println("Search the system.\n");
boolean fin = false;
int dec;
while (fin != true){
System.out.println("Please select which search type you want:\n");
System.out.println("1. Keywords.");
System.out.println("2. Category listing.");
System.out.println("3. Back\n");
dec = sc.nextInt();
if (dec == 1) {
// Do a keyword thing
fin = true;
}
else if (dec == 2) {
// Do a category thing
searchCategories();
fin = true;
}
else if (dec == 3) {
GuardSearch gs = new GuardSearch();
gs.Menu();
break;
}
}
}
public void searchCategories(){
// Create an empty list of subcategories, that will be added to when the user wants to add sub categories
LinkedList<Category> newSubCategories = new LinkedList<Category>();
// Create a list of .txt's relevant to the category
LinkedList<String> relevantArticles = new LinkedList<String>();
relevantArticles.add("example.txt");
LinkedList<String> dirListing = new LinkedList<String>();
//System.out.println("Please select your category:\n");
String s = "Example Category";
// Create the first category, passing in its name, an empty list of subCategories (which are of type Category), and a list of .txt's relevant to the category
Category firstCategory = new Category(s, newSubCategories, relevantArticles);
File wd = new File("/bin");
Process proc = null;
try {
proc = Runtime.getRuntime().exec("/bin/bash", null, wd);
}
catch (IOException e) {
e.printStackTrace();
}
if (proc != null) {
BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream()));
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(proc.getOutputStream())), true);
out.println("cd /var/tmp/cholland/GuardSearch/");
out.println("ls *.art");
out.println("exit");
String line;
System.out.println();
try {
int x = 1;
while ((line = in.readLine()) != null) {
System.out.println(x + ") " + line);
dirListing.add(line);
x++;
}
System.out.println("Please select the article you want:\n");
int dec = sc.nextInt();
//System.out.println(Arrays.toString(dirListing.toArray()));
System.out.println(dirListing.size());
try {
for (int y=1; y<=dirListing.size(); y++) {
if (y == dec){
boolean fin = false;
while (fin != true){
System.out.println("You chose: " + (dirListing.get(boundIndex(y))) + ". Opening file...");
System.out.println("===========================================================\n");
String text;
String filepath = ("/var/tmp/cholland/GuardSearch/" + (dirListing.get(boundIndex(y))));
BufferedReader br = null;
StringBuffer contents = new StringBuffer();
try {
br = new BufferedReader(new FileReader(filepath));
text = null;
while ((text = br.readLine()) != null) {
contents.append(text).append(System.getProperty("line.separator"));
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null)br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
text = (contents.toString());
System.out.println(text);
System.out.println("\n===========================================================\n");
fin = true;
}
}
}
}
catch (Exception e) {
e.printStackTrace();
}
proc.waitFor();
out.close();
in.close();
proc.destroy();
}
catch (Exception e) {
e.printStackTrace();
}
}
sc.close();
}
public int boundIndex(int x){
if (x != 0){
return (x - 1);
}
else {
return 0;
}
}
}
I think the problem is here decision = scan.nextInt();
NoSuchElementException will be thrown if no more tokens are available. This is caused by invoking nextInt() without checking if there's any integer available. You can hasNextInt() to check if any more tokens are available.
Something like:
if(scan.hasNextInt() )
decision = scan.nextInt(); // if there is another number
else
decision = 0; // nothing added in the input
The cause of the error is that you are closing the scanner at the end of searchCategories.

Reading from a text file as an arraylist/hashmap

Okay so here's an explanation of what I have to write:
getBreadInfo - reads bread.txt into an array list (containing bread
name, $, and price) and then assigns to an array breadInfo[], then
return this array for SandwichApp to display bread menu.
getBread - is similar to getBreadInfo, except it only contains the
bread name, and return another array bread[] for SandwichApp to figure
out which bread the user selected because user type in a number
associate with the bread (index+1), rather than bread name.
getMapBreadPrice - is similar to the above two, except it returns a
hash map containing pair values for bread name (key) and price (value)
for SandwichApp to figure out what is the price for the bread user
selected.
This is what I have written. Just wondering if this is correct or not?
public class SandwichDB {
private ArrayList<String> breadsList = null;
public String[] getBreadInfo()
{
breadsList = new ArrayList<>();
try (BufferedReader in =
new BufferedReader(
new FileReader("bread.txt")))
{
String line = in.readLine();
while (line != null)
{
String[] elems = line.split("~");
breadsList.add(elems[0]+ " $" + elems[1]);
}
}
catch(IOException e)
{
System.out.println(e);
return null;
}
String[] breadInfo = breadsList.toArray(new String[]{});
return breadInfo;
}
public String[] getBread()
{
breadsList = new ArrayList<>();
try (BufferedReader in =
new BufferedReader(
new FileReader("bread.txt")))
{
String line = in.readLine();
while (line != null)
{
String[] elems = line.split("~");
breadsList.add(elems[0]);
}
}
catch(IOException e)
{
System.out.println(e);
return null;
}
String[] bread = breadsList.toArray(new String[]{});
return bread;
}
public HashMap<String, String> getMapBreadPrice()
{
HashMap<String, String> mapBreadPrice = new HashMap<>();
String line, elems[];
try
{
FileReader fr = new FileReader("bread.txt");
BufferedReader br = new BufferedReader(fr);
while ((line=br.readLine()) != null)
{
elems = line.split("~");
mapBreadPrice.put(elems[0], elems[1]);
}
}
catch(IOException e)
{
System.out.println(e);
return null;
}
return mapBreadPrice;
}
}
The first readLine stands before the while and hence is not repeated. Hence the while does not end.
for (;;) {
String line = in.readLine();
if (line == null) {
break;
}
It seems like you're reading the same file 3 times in order to build 3 structures. You should build your data structures with one read of the file.

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