/*
 * Read in a text file using Scanner and useDelimiter
 * Manipulate the date and flag
 * Write new data to a new text file using PrintWriter
 */
package readingWritingTextFile;

import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;

public class ReadingWritingUI {
    
    public static void main(String[] args) {
        try {
            ReadingWritingManager mw = new ReadingWritingManager();
        } catch (IOException ex) {
            Logger.getLogger(ReadingWritingUI.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
    
}

================================================================================================

/*
 * Read in the date and format it to default
 * Add 45 days to the date
 * Read in the flag and compliment it.
 * Write the new data to a new file.
 */
package readingWritingTextFile;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;

public class ReadingWritingManager {
    
    PrintWriter pw;
    
    public ReadingWritingManager() throws IOException {
    
            boolean flag, newFlag;

        try {
            // The input file and the output file
            Scanner scFile = new Scanner(new File("textFile.txt"));
            pw = new PrintWriter(new FileWriter("newData.txt"));
            
            while(scFile.hasNextLine()){
                
                String line = scFile.nextLine();
                Scanner scLine = new Scanner(line).useDelimiter("#");
                String dateSt = scLine.next();
                LocalDate theDate = LocalDate.parse(dateSt, DateTimeFormatter.ofPattern("dd-MM-yyyy"));
                LocalDate newDate = theDate.plusDays(45);
                
                flag = scLine.nextBoolean();
                
				// Compliment the boolean flag
                if(flag == true)
                    newFlag = false;
                else
                    newFlag = true;
                
                // Parse date and flag to String
                pw.println("" + newDate + "#" + newFlag);
            }
            
            pw.close();
            System.out.println("Reading Write successful");
            
        } catch (FileNotFoundException ex) {
            Logger.getLogger(ReadingWritingManager.class.getName()).log(Level.SEVERE, null, ex);
            System.out.println("Error finding file");
        }
}
}

===========================================================================================================

TEXT File - INPUT

14-09-2023#true
17-10-2022#false
26-01-2023#false
09-09-2022#true

=========================================================================================================

OUTPUT TO NEW File

2023-10-29#false
2022-12-01#true
2023-03-12#true
2022-10-24#false