Question

Write a program that reverses a text file by using a stack. The user interface must consist of 2 list boxes and 3 buttons. The 3 buttons are: Read - reads the text file into list box 1. Reverse - reverses the items in list box 1 by pushing them onto stack 1, then popping them from stack 1 (in the reverse order) and adding them to list box 2. Write - writes the contents of list box 2 to a new text file. At first, only the Read button is enabled. After it is clicked, it is disabled and the Reverse button is enabled. After it is clicked, it is disabled and the Write button is enabled. After it is clicked, it is disabled. The name of the input text file is "input.txt". The input text file will contain no more than 100 lines of text. This fact is not needed by the program. It simply means that memory usage is not an issue. The name of the output text file is "output.txt". Notes: 1. The name of your main class should be ReverseFileViaStack. 2. Use the Java class library Stack class for your stack. 3. Use a border layout for your contents pane. 4. In the north region include the following title: Reverse a Text File via a Stack. 5. Use a panel in the center region to contain the 2 list boxes (side-by-side). 6. Place the 3 buttons in the south region. 7. A useful resource for this project is the week 5 video: Java GUI List Components

Example Programming Project Output Sample input file contents: a ab abc abcd abcde abcdef abcdefg abcdefgh abcdefghi abcdefghij abcdefghijk abcdefghijkl abcdefghijklm abcdefghijklmn abcdefghijklmno abcdefghijklmnop abcdefghijklmnopq abcdefghijklmnopqr abcdefghijklmnopqrs abcdefghijklmnopqrst abcdefghijklmnopqrstu abcdefghijklmnopqrstuv abcdefghijklmnopqrstuvw abcdefghijklmnopqrstuvwx abcdefghijklmnopqrstuvwxy abcdefghijklmnopqrstuvwxyz

Answer 1

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
import java.util.Stack;
import javax.swing.DefaultListModel;
import javax.swing.ListModel;

public class FileRead extends javax.swing.JFrame {

public FileRead() {
initComponents();
}

@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

jScrollPane1 = new javax.swing.JScrollPane();
jList1 = new javax.swing.JList<>();
jScrollPane2 = new javax.swing.JScrollPane();
jList2 = new javax.swing.JList<>();
btnRead = new javax.swing.JButton();
btnReverse = new javax.swing.JButton();
btnWrite = new javax.swing.JButton();

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

jScrollPane1.setViewportView(jList1);

jScrollPane2.setViewportView(jList2);

btnRead.setText("Read");
btnRead.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnReadActionPerformed(evt);
}
});

btnReverse.setText("Reverse");
btnReverse.setEnabled(false);
btnReverse.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnReverseActionPerformed(evt);
}
});

btnWrite.setText("Write");
btnWrite.setEnabled(false);
btnWrite.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnWriteActionPerformed(evt);
}
});

javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(41, Short.MAX_VALUE)
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, 115, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(32, 32, 32)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 115, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(48, 48, 48))
.addGroup(layout.createSequentialGroup()
.addGap(60, 60, 60)
.addComponent(btnRead)
.addGap(18, 18, 18)
.addComponent(btnReverse)
.addGap(18, 18, 18)
.addComponent(btnWrite)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(30, 30, 30)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jScrollPane2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(32, 32, 32)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(btnRead)
.addComponent(btnReverse)
.addComponent(btnWrite))
.addContainerGap(20, Short.MAX_VALUE))
);

pack();
}// </editor-fold>

private void btnReadActionPerformed(java.awt.event.ActionEvent evt) {
try {
//input file
File f = new File("H://inputfile.txt");
//model to add elements to the list
DefaultListModel input = new DefaultListModel();
//to read values from the file
Scanner sc = new Scanner(f);
while (sc.hasNext()) {
input.addElement(sc.next());
}
sc.close();
//adds elements to the list
jList2.setModel(input);
//disables read button
btnRead.setEnabled(false);
//enables reverse button
btnReverse.setEnabled(true);
} catch (FileNotFoundException ex) {
System.out.println(ex);
}

}   
Stack s = new Stack();

private void btnReverseActionPerformed(java.awt.event.ActionEvent evt) {   
ListModel input = new DefaultListModel<>();
DefaultListModel output = new DefaultListModel<>();
input = jList2.getModel();
//adds elements to the stack
for (int i = 0; i < input.getSize(); i++) {
s.push(input.getElementAt(i).toString());
}
//add elements to 2nd list from stack hence reversing them
for (int i = 0; i < input.getSize(); i++) {
output.addElement(s.pop());
}
jList1.setModel(output);
btnReverse.setEnabled(false);
btnWrite.setEnabled(true);
}

private void btnWriteActionPerformed(java.awt.event.ActionEvent evt) {   
PrintWriter p = null;
try {
// TODO add your handling code here:
ListModel output = new DefaultListModel<>();
output = jList1.getModel();
//output file
File f = new File("H://outputfile.txt");
f.createNewFile();
//writes data from 2nd list to file
p = new PrintWriter(f);
for (int i = 0; i < output.getSize(); i++) {
p.write(output.getElementAt(i).toString() + " \n");
}
} catch (FileNotFoundException ex) {
System.out.println(ex);
} catch (IOException ex) {
System.out.println(ex);
} finally {
p.close();
btnWrite.setEnabled(false);
btnRead.setEnabled(true);
}

}

/**
* @param args the command line arguments
*/
public static void main(String args[]) {
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(FileRead.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(FileRead.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(FileRead.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(FileRead.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>

/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new FileRead().setVisible(true);
}
});
}

// Variables declaration - do not modify   
private javax.swing.JButton btnRead;
private javax.swing.JButton btnReverse;
private javax.swing.JButton btnWrite;
private javax.swing.JList<String> jList1;
private javax.swing.JList<String> jList2;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JScrollPane jScrollPane2;
// End of variables declaration   
}

input file

a ab abc abcd abcde abcdef abcdefg abcdefgh abcdefghi abcdefghij abcdefghijk abcdefghijkl abcdefghijklm abcdefghijklmn abcdefghijklmno abcdefghijklmnop abcdefghijklmnopq abcdefghijklmnopqr abcdefghijklmnopqrs abcdefghijklmnopqrst abcdefghijklmnopqrstu abcdefghijklmnopqrstuv abcdefghijklmnopqrstuvw abcdefghijklmnopqrstuvwx abcdefghijklmnopqrstuvwxy abcdefghijklmnopqrstuvwxyz

output file

abcdefghijklmnopqrstuvwxyz
abcdefghijklmnopqrstuvwxy
abcdefghijklmnopqrstuvwx
abcdefghijklmnopqrstuvw
abcdefghijklmnopqrstuv
abcdefghijklmnopqrstu
abcdefghijklmnopqrst
abcdefghijklmnopqrs
abcdefghijklmnopqr
abcdefghijklmnopq
abcdefghijklmnop
abcdefghijklmno
abcdefghijklmn
abcdefghijklm
abcdefghijkl
abcdefghijk
abcdefghij
abcdefghi
abcdefgh
abcdefg
abcdef
abcde
abcd
abc
ab
a

ab abc abcd abcde Read Reverse Write

abcdefghijklmno ab abc abcd abcde abcdefghijklmnd Read Reverse Write