MyDocumentListener.java Source code

Introduction

Here is the source code for MyDocumentListener.java

Source

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.Document;

class MyDocumentListener implements DocumentListener {
    final String newline = "\n";

    public void insertUpdate(DocumentEvent e) {
        updateLog(e, "inserted into");
    }

    public void removeUpdate(DocumentEvent e) {
        updateLog(e, "removed from");
    }

    public void changedUpdate(DocumentEvent e) {
        //Plain text components don't fire these events.
    }

    public void updateLog(DocumentEvent e, String action) {
        Document doc = (Document) e.getDocument();
        int changeLength = e.getLength();
        System.out.println(changeLength + " character" + ((changeLength == 1) ? " " : "s ") + action + " "
                + doc.getProperty("name") + "." + newline + "  Text length = " + doc.getLength() + newline);
    }
}

public class UsingDocumentListener {

    public static void main(String[] a) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JTextField textField = new JTextField();

        textField.getDocument().addDocumentListener(new MyDocumentListener());
        textField.getDocument().putProperty("name", "Text Field");

        frame.add(textField);

        frame.setSize(300, 200);
        frame.setVisible(true);
    }

}