Create a Program to Implement String Manipulation in Java Assignment Solution.

import java.io.BufferedReader;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.swing.*;

import javax.swing.filechooser.FileNameExtensionFilter;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

public class App extends JFrame {

public static void main(String[] args) throws Exception {

// list of polynomials

List polynomials = new ArrayList();

JFrame f = new JFrame();

JButton btn = new JButton("Open file...");

btn.setBounds(20,20,100,20);

JTextArea txt = new JTextArea();

txt.setBounds(20, 60, 300, 300);

f.add(txt);

btn.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

JFileChooser fileChooser = new JFileChooser();

fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);

FileNameExtensionFilter filter = new FileNameExtensionFilter("Text Files", "txt");

fileChooser.setFileFilter(filter);

int result = fileChooser.showOpenDialog(btn);

if (result != JFileChooser.CANCEL_OPTION) {

File fileName = fileChooser.getSelectedFile();

if ((fileName == null) || (fileName.getName().equals("")))

{

txt.setText("No file selected!");

} else {

// read file

try

{

BufferedReader reader = new BufferedReader(new FileReader(fileName.getAbsolutePath()));

String line = reader.readLine();

while(line != null)

{

Polynomial poly = new Polynomial(line);

polynomials.add(poly);

txt.setText(txt.getText() + poly.toString() + "\n");

line = reader.readLine();

}

reader.close();

// check ordered

boolean res = OrderedList.checkSorted(polynomials);

txt.setText(txt.getText() + "Polynomials sorted: " + res + "\n");

}

catch(IOException ex)

{

// nothing

} catch (InvalidPolynomialSyntax e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}

}

}

}

});

f.add(btn);

f.setSize(400,500);

f.setLayout(null);

f.setVisible(true);

}

}