Question

• This assignment will give you practice in Handling Exceptions and using File I/O. Language for this program is JAVA

  Part One

• A hotel salesperson enters sales in a text file. Each line contains the following, separated by semicolons:
  • The name of the client,
  • the service sold (such as Dinner, Conference, Lodging, and so on),
  • the amount of the sale,
  • and the date of that event.
• Prompt the user for data to write the file.

  Part Two

• Write a program that reads the text file as described above, and that writes a separate file for each service category, containing the entries for that category. Name the output files Dinner.txt, Conference.txt, and so on.
• Enter the name of the output file from Part One as a command line argument.

  Both Parts

• For all programs, catch and handle the Exceptions appropriately and validate the input data where needed.
• Display an error if the sales file does not exist or the format is incorrect.
• Also, create your own exception to handle "unknown transaction" exceptions.

  Samples:

  • Contents of sales.txt (file created in part one)

    John Public;Dinner;29.95;6/7/2014
    Jane Public;Conference;499.00;8/9/2014
    Abby Lawrence;Dinner;23.45;10/10/2014
    

  • Contents of Dinner.txt (file created in part two)

    John Public;Dinner;29.95;6/7/2014
    Abby Lawrence;Dinner;23.45;10/10/2014
    

  • Contents of Conference.txt (file created in part two)

    Jane Public;Conference;499.0;8/9/2014

Answer 1

The program to write data to Sample.txt is SalesInfo.java and for the part 2 its HotelRecords.java

1. Also, there is a class named UnknownTransaction.java that is custom exception , whenever the format of the file is not correct this exception is thrown.
2. Please make sure you go through comments once before running the program, it is very important specially while doing inputs.
3. Wherever filename or path is asked please enter in the format: C:\\Users\\<Username>\\Desktop, if you want to create file in desktop, otherwise make inputs accordingly.(Also specified in the comment)

Part one:

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
public class SalesInfo {
    public static void main(String[] args) throws Exception {
        File file=null;
        // Enter the name of the file from which data has to be parsed , example : Sample.txt
        /*If the file is C:\Users\<name>\Desktop\Sample.txt
         *  then Enter the filename as C:\\Users\\<name>\\Desktop\\Sample.txt
         * Because java takes '\' as escape sequence hence '\\' is used . Please enter the filename properly
         */
        BufferedReader in= new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter the filename from which data has to be parsed");
        String filename=in.readLine();
        try {
            file = new File(filename);
            if(!file.exists())
                file.createNewFile();
            while(true){
                    System.out.println("Enter the name of Client: ");
                    String client=in.readLine();
                    System.out.println("Enter the Service category sold: ");
                    String Category=in.readLine();
                    System.out.println("Enter the amount of the sale: ");
                    String amount=in.readLine();
                    System.out.println("Please enter the date in the correct format(dd/MM/yyyy)");
                    String date=in.readLine();
                    String value= client+";"+Category+";"+amount+";"+date;
                    System.out.println(value);
                    FileWriter fr = new FileWriter(file, true);
                    BufferedWriter bw = new BufferedWriter(fr);
                    bw.write("\n"+value);
                    
                    bw.close();
                    System.out.println("Do you want to input more data(Y/N) ?");
                    String s=in.readLine();
                    System.out.println(s);
                    if(s.equals("N"))
                        break;
            }
            
           
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        catch(IOException e) {
            e.printStackTrace();
        }
//        finally {
//            br.close();
//        }
    }
}

Part 2:

import java.io.*;
public class HotelRecords {
    public static void main(String[] args) throws Exception {
        File file=null;
        BufferedReader br=null;
        
        // Enter the name of the file from which data has to be parsed , example : Sample.txt
        /*If the file is C:\Users\<name>\Desktop\Sample.txt
         *  then Enter the filename as C:\\Users\\<name>\\Desktop\\Sample.txt
         * Because java takes '\' as escape sequence hence '\\' is used . Please enter the filename properly
         */
        BufferedReader in= new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter the filename from which data has to be parsed");
        String filename=in.readLine();
        
        try {
            file = new File(filename);
            
            //if there is no such file , it throws file not found exception
            br = new BufferedReader(new FileReader(file));

            String st;
            while ((st = br.readLine()) != null) {
                String input[] = st.split(";");
                
                //Please enter the path as described above with '\\' in place of '\'
                System.out.println("Enter the path where you want to create the files");
                String path=in.readLine();
                
                //The data separated by ; has to be 4 according to question, if not throws UnknownTrnsaction
                if(input.length==4){
                        File f1 = new File(path +"\\"+ input[1] + ".txt");
                        // If the file does not exists
                        if (!f1.exists())
                            f1.createNewFile();
                        FileWriter fr = new FileWriter(f1, true);
                        BufferedWriter bw = new BufferedWriter(fr);
                        bw.write(st+"\n");
                        bw.close();
                }
                else{
                        throw new UnknownTransaction("The format for the transaction is not known");
                }
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        catch(UnknownTransaction e){
                System.out.println(e.getMessage());
        }
        catch(IOException e) {
            e.printStackTrace();
        }
        finally {
                
            br.close();
        }
    }
}

Custom Exception:

class UnknownTransaction extends Exception 
{ 
    public UnknownTransaction(String s) 
    { 
        // Call constructor of parent Exception 
        super(s); 
    } 
}