public void insertString(int offs, String str, AttributeSet a)
			throws BadLocationException
	{
		if (str != null)
		{
			for (int index = 0; index < str.length(); index++)
			{
				char c = str.charAt(index);

				if (!Character.isDigit(c))
				{
					return;
				}
			}
		}
		super.insertString(offs, str, a);
	}