Java Notes: Example - Read Words

// File   : readwords/ReadWordsGUI.java
// Purpose: Read a file and display all words in it.
// Author : Fred Swartz
// Date   : 2005-03-10

package readwords;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;

class ReadWordsGUI extends JPanel {
    
    //... Instance variables
    JTextArea    m_wordListTA  = new JTextArea(25, 15);
    JFileChooser m_fileChooser = new JFileChooser();
    
    ArrayList<String> m_words = new ArrayList<String>();
    
    //======================================================== constructor
    ReadWordsGUI() {
        JButton openButton = new JButton("Open");
        
        //... Add listeners
        openButton.addActionListener(new OpenAction());
        
        //... Layout components
        this.setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
        this.add(openButton);
        this.add(new JScrollPane(m_wordListTA));
    }
    
    /////////////////////////////////////////////////// inner listener class
    class OpenAction implements ActionListener {
        public void actionPerformed(ActionEvent ae) {
            int retval = m_fileChooser.showOpenDialog(ReadWordsGUI.this);
            if (retval == JFileChooser.APPROVE_OPTION) {
                File file = m_fileChooser.getSelectedFile();
                try {
                    Scanner wordScanner = new Scanner(file);
                    wordScanner.useDelimiter("[^A-Za-z]+");
                    while (wordScanner.hasNext()) {
                        m_words.add(wordScanner.next());
                    }
                    
                    //... Sort the words alphabetically.
                    Collections.sort(m_words);