So I'm working on a database-type program for the Java course that i'm doing and i seem to have run into a bit of a roadblock. This class compiles and runs alright but where i have a problem with it is when i try to amend the text file using the same class. All it does is overwrite whatever is on the txt file. I've tried to include a method that reads the text file first and then includes the contents in the output but i cant get it to work because the second i use Formatter.format(Scanner(system.in)) (if that makes sense) it just replaces whatever was in the file with the new input. (I hope I'm coherent.. If not, just let me know :P)

This is the code:

import java.io.File;
import java.io.FileNotFoundException;
import java.lang.SecurityException;
import java.util.Formatter;
import java.util.FormatterClosedException;
import java.util.NoSuchElementException;
import java.util.Scanner;


public class CreateTextFile
{

   private Formatter output; 

   public void openFile()
   {
      try
      {
         output = new Formatter( "clients.txt" ); 
      } 
      catch ( SecurityException securityException )
      {
         System.err.println(
            "You do not have write access to this file." );
         System.exit( 1 ); 
      } 
      catch ( FileNotFoundException fileNotFoundException )
      {
         System.err.println( "Error opening or creating file." );
         System.exit( 1 ); 
      } 
   } 

   
   public void addRecords()
   {
      
      AccountRecord record = new AccountRecord();
      Scanner input = new Scanner( System.in );
      
      System.out.printf( "%s\n%s\n%s\n%s\n\n",
         "To terminate input, type the end-of-file indicator ",
         "when you are prompted to enter input.",
         "On UNIX/Linux/Mac OS X type <ctrl> d then press Enter",
         "On Windows type <ctrl> z then press Enter" );

      System.out.printf( "%s\n%s", 
         "Enter product code, Description, width, height, depth and weight.",
         "? " );
         
      while ( input.hasNext() ) 
      {
         try 
         {
            
            record.setAccount( input.next() ); 
            record.setFirstName( input.next() ); 
            record.setLastName( input.nextDouble() ); 
            record.setBalance( input.nextDouble() ); 
            record.setDepth(input.nextDouble());
            record.setWeight(input.nextDouble());
            
            if ( ((record.getAccount()).length() > 0) &&  ((record.getAccount()).length() <=4 ))
            {
               
               output.format( "%s %s %.2f %.2f %.2f %.2f\n", record.getAccount(), 
                  record.getFirstName(), record.getLastName(),
                  record.getBalance(), record.getDepth(), record.getWeight() );
            } 
            else
            {
               System.out.println(
                  "Product Code is between 0 and 4 characters" );
            } 
         }
         catch ( FormatterClosedException formatterClosedException )
         {
            System.err.println( "Error writing to file." );
            return;
         } 
         catch ( NoSuchElementException elementException )
         {
            System.err.println( "Invalid input. Please try again." );
            input.nextLine(); 
         } 

         System.out.printf( "%s\n%s", 
         "Enter product code, Description, width, height, depth and weight.",
         "? " );
      } 
   } 

   
   public void closeFile()
   {
      if ( output != null )
         output.close();
   } 
}

Is there some way to indicate to Formatter to skip like x amount of lines. Cos then i could count the lines with LineNumberReader from java.io.

Thanks for lookin,
Khodz

Edited 6 Years Ago by Khodz: n/a

Yea that's exactly what I'm trying to do. Thanks for the speedy response.

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