why the program keep looping

[su zhen]

Anyone can help me see, everytime i press 3 or anything to do with displaying data from the txt. file the data keep showing and repeat alot of times.

import java.io.*;
import java.util.*;
public class miniProject {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
                //Declare variables for reading file
        FileReader fr = null;
        BufferedReader br = null;
        String inFile = "products.txt";
        String line = "";

        //Declare the variables
        String number;
        String brand;
        String model;
        String category;
        String price;
        String stock;

        //Input prompts
        final String Input_prompt = "\nPlease select one option: "+ "\n1.Find Brand or Model of the product"+"\n2.Find Category"+
                                    "\n3.Display all Products Available"+"\n4.Add in new Product"+"\n5.Remove existing Product"+
                                    "\n6. Exit"+"\nChoice: ";
        final String selectCategory = "\nPlease Select a product category to search (Choice 1-7) : "+ "\n1.Desktop"+ "\n2.Laptop"+
                                      "\n3.Music Player"+"\n4.Camera"+ "\n5.Printer"+ "\n6.Storage devices";
       //Declare and instantiate a new LinkedList
       LinkedList<Products_106316B> list = new LinkedList <Products_106316B>();
       try {
            //Instantiate FileReader & BufferedReader objects
            fr = new FileReader(inFile);
            br = new BufferedReader(fr);

            //Read one line from the file
            line = br.readLine();
            //While line is not null
            while (line != null) {
                //Tokenize the record
                StringTokenizer tokenizer = new StringTokenizer(line, "|");
                number = tokenizer.nextToken();
                brand = tokenizer.nextToken();
                model = tokenizer.nextToken();
                category = tokenizer.nextToken();
                price = tokenizer.nextToken();
                stock = tokenizer.nextToken();

                //Create a new vehicle object of the record
                Products_106316B Products = new Products_106316B(number,brand,model,category,price,stock);
                //Add this item object into the ArrayList
                list.addFirst(Products);
                //Read another line from file
                line = br.readLine();
            }
            //Close BufferedReader
            br.close();
        }
        catch (FileNotFoundException e) {
            System.out.println("The file " + inFile + " was not found");
        } catch (IOException e) {
            System.out.println("Reading error!");
        }
        finally
        {
            //Close FileReader
            if(fr!=null){
                try{
                    fr.close();
                }
                catch(IOException e){
                    System.out.println("Error closing file!");
                }
            }
        }



        try{

            //Create readers to read from user input
           BufferedReader reader = new BufferedReader(new InputStreamReader (System.in));
           //Print input prompts
        System.out.println(Input_prompt);
            //Read one line from user input
            line = reader.readLine();
            while (!line.equals("0")) {
                //read one line from user
                Collections.sort(list);
                int counter=0;
                if (line.equals("1")) {
                    //Read one line from user input
                    System.out.println("Please key in a product brand or model: ");
                    
                        br = new BufferedReader(new InputStreamReader(System.in));
                        line = reader.readLine();
                        //Loop through all the records in the linkedList
                        for (int i = 0; i < list.size(); i++) {
                            //if the record is the same as the input from user
                            //(Hint: user contains() in string class to check whether
                            //search word is found in the records
                            if (list.get(i).brand.contains(line) || list.get(i).model.contains(line)){ //printout the information of the vehicle

                                System.out.println(list.get(i));
                                counter=counter+1;
                            }

                        }

                    //}//try
                                        if (counter == 0) {
                        System.out.println("Record not found");
                    }

                }

                    else if (line.equals("2")) {
                    //Print selectCategory
                    System.out.println(selectCategory);
                    //Read one line from user input
                    line = reader.readLine();
                    if(line.equals("1")){
                        
                            for (int i = 0; i < list.size(); i++){
                                if(list.get(i).category.contains("desktop"))
                                System.out.println(list.get(i));
                                
                            }
                    }
                     else if (line.equals("2")){
                            for (int i = 0; i < list.size(); i++){
                                if(list.get(i).category.contains("laptop"))
                                System.out.println(list.get(i));
                               
                            }
                    }
                      else if (line.equals("3")){
                            for (int i = 0; i < list.size(); i++){
                                if(list.get(i).category.contains("music player"))
                                System.out.println(list.get(i));
                                
                            }
                    }
                        else if (line.equals("4")){
                            for (int i = 0; i < list.size(); i++){
                                if(list.get(i).category.contains("camera"))
                                System.out.println(list.get(i));
                                
                            }
                    }
                        else if (line.equals("5")){
                            for (int i = 0; i < list.size(); i++){
                                if(list.get(i).category.contains("printer"))
                                System.out.println(list.get(i));
                        
                            }
                    }
                        else if (line.equals("6")){
                            for (int i = 0; i < list.size(); i++){
                                if(list.get(i).category.contains("storage devices"))
                                System.out.println(list.get(i));
                              
                            }
                    }
                }
                else if (line.equals("3")){
                    //Display the whole list
                    for(int n = 0; n<list.size();n++){
                        System.out.println(list.get(n) );
                    }
                }
                else if (line.equals("4")){
                    //User data input
                    System.out.println("Please key in your data in the format:" +
                                       "\n <Number>|<Brand>|<Model>|<Category>|<Price>|<Stock> :");
 
                   
                    BufferedReader Insert = new BufferedReader(new InputStreamReader(System.in));
                    line = Insert.readLine();
                    FileWriter fw = new FileWriter(inFile);
                    BufferedWriter bw = new BufferedWriter(fw);
                    PrintWriter pw = new PrintWriter(bw);

                    //Tokenize the record
                    StringTokenizer tokenizer = new StringTokenizer(line, "|");
                    number = tokenizer.nextToken();
                    brand = tokenizer.nextToken();
                    model = tokenizer.nextToken();
                    category = tokenizer.nextToken();
                    price = tokenizer.nextToken();
                    stock = tokenizer.nextToken();

           
                    Products_106316B Products = new Products_106316B(number,brand,model,category,price,stock);
                    list.add(Products);
                    pw.println(Products);
                    pw.close();

                }
                else if (line.equals("5")){
                    //show the data list
                   for(int i = 0; i<list.size();i++)
                        System.out.println(list.get(i) + "");
                    //Data delete
                    System.out.println("Key in the index of the data you want to remove: ");
                        BufferedReader delete = new BufferedReader (new InputStreamReader (System.in));
                        line = delete.readLine();
    /*
                //Tokenize the record
                StringTokenizer tokenizer = new StringTokenizer(line, "|");
                    number = tokenizer.nextToken();
                    brand = tokenizer.nextToken();
                    model = tokenizer.nextToken();
                    category = tokenizer.nextToken();
                    price = tokenizer.nextToken();
                    stock = tokenizer.nextToken();

                    //Create a new vehicle object of the record
                    Products_106316B Products = new Products_106316B(number, brand, model, category, price, stock);
                    //Add this item object into the ArrayList
                    list.remove(Products.number);
                    br.close();
*/
                    FileWriter fwp = new FileWriter(inFile);
                    BufferedWriter bwp = new BufferedWriter(fwp);
                    PrintWriter del = new PrintWriter(bwp);

                    try {



                        for (int n = 0; n < list.size(); n++) {

                            if (list.get(n).number.toUpperCase().contains(line.toUpperCase())) {
                                list.remove(n);


                            }
                                del.close();

                            }

                        } catch (NoSuchElementException e) {
                            System.out.print("key in full format");
                        }

                } else if (line.equals("6")) {
                    System.exit(0);

                }
            }
            System.out.println(Input_prompt);
            line = reader.readLine();
        }//try
        catch (Exception e) {
            System.out.println("Input error!");
        }

    }//end of main
}

    

class file-

public class Products_106316B implements Comparable<Products_106316B> {
 //Declare the variables
    String number;
    String brand;
    String model;
    String category;
    String price;
    String stock;

    //Creates a constructor to store all the fields into the variables
    public Products_106316B(String number, String brand, String model, String category, String price, String stock){
        this.number = number;
        this.brand = brand;
        this.model = model;
        this.category = category;
        this.price = price;
        this.stock = stock;

    }
    //Create a toString() method to return string in the same format as the input record
    public String toString(){
        return (number+ ", "+brand+", "+model+", "+category+", $"+price+", "+stock);
    }
    public int compareTo(Products_106316B other) {
        int result;

        if (brand.equals(other.brand)) {
            result = brand.compareTo(other.brand);
        } else {
            result = model.compareTo(other.model);
        }
        return result;
    }
}

.txt data
1|Acer|Aspire 4750G|laptop|1,198|1000
2|Dell|XPS 8300|desktop|1,199|222
3|Dell|1130n|printer|172|1231
4|Apple|ipod Touch|music player|8GB: $328, 16GB:$428, 32GB:588|322
5|Nikon|Coolpix P300|camera|599|324
6|Apple|MacBook|laptop|1348|60
7|Fujifilm|Finepix Jx200|camera|159|279
8|Acer|Aspire M3970|desktop|999|33
9|Fujitsu|Lifebook P521|laptop|599|464
10|Creative|ZEN X-Fi2|music player|8GB:159|54

[Maneesh Godbole]

Your code has this pattern
1) Read a line
2) Check the condition of the line in a while loop and execute some logic.
However, your line never changes.

You need to change it so something like

while((line=br.readLine()) != null)

This way, for every iteration, the value of line will change

[Campbell Ritchie]

Why are you using StringTokenizer? Have you read its documentation? Why are you using Readers when a Scanner is so much easier to use?