Text fields and Java events : TextField « Swing JFC « Java

Text fields and Java events

Text fields and Java events

// : c14:TextFields.java
// Text fields and Java events.
// <applet code=TextFields width=375 height=125></applet>
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.PlainDocument;

public class TextFields extends JApplet {
  private JButton b1 = new JButton("Get Text"), b2 = new JButton("Set Text");

  private JTextField t1 = new JTextField(30), t2 = new JTextField(30),
      t3 = new JTextField(30);

  private String s = new String();

  private UpperCaseDocument ucd = new UpperCaseDocument();

  public void init() {
    ucd.addDocumentListener(new T1());
    b1.addActionListener(new B1());
    b2.addActionListener(new B2());
    DocumentListener dl = new T1();
    t1.addActionListener(new T1A());
    Container cp = getContentPane();
    cp.setLayout(new FlowLayout());

  class T1 implements DocumentListener {
    public void changedUpdate(DocumentEvent e) {

    public void insertUpdate(DocumentEvent e) {
      t3.setText("Text: " + t1.getText());

    public void removeUpdate(DocumentEvent e) {

  class T1A implements ActionListener {
    private int count = 0;

    public void actionPerformed(ActionEvent e) {
      t3.setText("t1 Action Event " + count++);

  class B1 implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      if (t1.getSelectedText() == null)
        s = t1.getText();
        s = t1.getSelectedText();

  class B2 implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      t1.setText("Inserted by Button 2: " + s);

  public static void main(String[] args) {
    run(new TextFields(), 375, 125);
  public static void run(JApplet applet, int width, int height) {
    JFrame frame = new JFrame();
    frame.setSize(width, height);

class UpperCaseDocument extends PlainDocument {
  private boolean upperCase = true;

  public void setUpperCase(boolean flag) {
    upperCase = flag;

  public void insertString(int offset, String str, AttributeSet attSet)
      throws BadLocationException {
    if (upperCase)
      str = str.toUpperCase();
    super.insertString(offset, str, attSet);

} ///:~


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