Main.java Source code

Introduction

Here is the source code for Main.java

Source

/*
 * Copyright (C) 2001-2003 Colin Bell
 * colbell@users.sourceforge.net
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
import java.awt.Toolkit;

import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.PlainDocument;

/**
 * This class is a <CODE>TextField</CODE> that only allows integer
 * values to be entered into it.
 *
 * @author <A HREF="mailto:colbell@users.sourceforge.net">Colin Bell</A>
 */
public class Main {
    public static void main(String[] argv) {

        JOptionPane.showMessageDialog(null, new IntegerField());

    }
}

class IntegerField extends JTextField {
    /**
     * Default ctor.
     */
    public IntegerField() {
        super();
    }

    /**
     * Ctor specifying the field width.
     *
     * @param cols  Number of columns.
     */
    public IntegerField(int cols) {
        super(cols);
    }

    /**
     * Retrieve the contents of this field as an <TT>int</TT>.
     *
     * @return  the contents of this field as an <TT>int</TT>.
     */
    public int getInt() {
        final String text = getText();
        if (text == null || text.length() == 0) {
            return 0;
        }
        return Integer.parseInt(text);
    }

    /**
     * Set the contents of this field to the passed <TT>int</TT>.
     *
     * @param value The new value for this field.
     */
    public void setInt(int value) {
        setText(String.valueOf(value));
    }

    /**
     * Create a new document model for this control that only accepts
     * integral values.
     *
     * @return  The new document model.
     */
    protected Document createDefaultModel() {
        return new IntegerDocument();
    }

    /**
     * This document only allows integral values to be added to it.
     */
    static class IntegerDocument extends PlainDocument {
        public void insertString(int offs, String str, AttributeSet a) throws BadLocationException {
            if (str != null) {
                try {
                    Integer.decode(str);
                    super.insertString(offs, str, a);
                } catch (NumberFormatException ex) {
                    Toolkit.getDefaultToolkit().beep();
                }
            }
        }
    }
}