Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.HeadlessException;

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;

public class Main extends JFrame {
    public Main() throws HeadlessException {
        setSize(200, 200);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new FlowLayout(FlowLayout.LEFT));

        DocumentFilter filter = new UppercaseDocumentFilter();

        JTextField firstName = new JTextField();
        firstName.setPreferredSize(new Dimension(100, 20));
        ((AbstractDocument) firstName.getDocument()).setDocumentFilter(filter);

        JTextField lastName = new JTextField();
        lastName.setPreferredSize(new Dimension(100, 20));
        ((AbstractDocument) lastName.getDocument()).setDocumentFilter(filter);

        add(firstName);
        add(lastName);
    }

    public static void main(String[] args) {
        new Main().setVisible(true);
    }

}

class UppercaseDocumentFilter extends DocumentFilter {
    public void insertString(DocumentFilter.FilterBypass fb, int offset, String text, AttributeSet attr)
            throws BadLocationException {

        fb.insertString(offset, text.toUpperCase(), attr);
    }

    public void replace(DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs)
            throws BadLocationException {

        fb.replace(offset, length, text.toUpperCase(), attrs);
    }
}