Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.BorderLayout;
import java.text.NumberFormat;

import javax.swing.JButton;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultFormatterFactory;
import javax.swing.text.DocumentFilter;
import javax.swing.text.InternationalFormatter;

public class Main {
    public static void main(String... args) {
        JFrame frame = new JFrame();
        JSpinner jspinner = makeDigitsOnlySpinnerUsingDocumentFilter();
        frame.getContentPane().add(jspinner, BorderLayout.CENTER);
        frame.getContentPane().add(new JButton("just another widget"), BorderLayout.SOUTH);
        frame.pack();
        frame.setVisible(true);
    }

    private static JSpinner makeDigitsOnlySpinnerUsingDocumentFilter() {
        JSpinner spinner = new JSpinner(new SpinnerNumberModel());
        JSpinner.NumberEditor jsEditor = (JSpinner.NumberEditor) spinner.getEditor();
        JFormattedTextField textField = jsEditor.getTextField();
        DocumentFilter digitOnlyFilter = new DocumentFilter() {
            @Override
            public void insertString(FilterBypass fb, int offset, String string, AttributeSet attr)
                    throws BadLocationException {
                if (stringContainsOnlyDigits(string)) {
                    super.insertString(fb, offset, string, attr);
                }
            }

            @Override
            public void remove(FilterBypass fb, int offset, int length) throws BadLocationException {
                super.remove(fb, offset, length);
            }

            @Override
            public void replace(FilterBypass fb, int offset, int length, String text, AttributeSet attrs)
                    throws BadLocationException {
                if (stringContainsOnlyDigits(text)) {
                    super.replace(fb, offset, length, text, attrs);
                }
            }

            private boolean stringContainsOnlyDigits(String text) {
                for (int i = 0; i < text.length(); i++) {
                    if (!Character.isDigit(text.charAt(i))) {
                        return false;
                    }
                }
                return true;
            }
        };

        NumberFormat format = NumberFormat.getPercentInstance();
        format.setGroupingUsed(false);
        format.setGroupingUsed(true);
        format.setMaximumIntegerDigits(10);
        format.setMaximumFractionDigits(2);
        format.setMinimumFractionDigits(5);
        textField.setFormatterFactory(new DefaultFormatterFactory(new InternationalFormatter(format) {
            @Override
            protected DocumentFilter getDocumentFilter() {
                return digitOnlyFilter;
            }
        }));
        return spinner;
    }
}