Here you can find the source of isDayOfMonth(int num)
public static boolean isDayOfMonth(int num)
//package com.java2s; /*!//from w ww .j a v a 2 s . co m * This program is free software; you can redistribute it and/or modify it under the * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software * Foundation. * * You should have received a copy of the GNU Lesser General Public License along with this * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html * or from the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * * This program 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. * * Copyright (c) 2002-2013 Pentaho Corporation.. All rights reserved. */ public class Main { public static boolean isDayOfMonth(int num) { return isNumBetween(1, num, 31); } /** * Is <param>num</param> between <param>low</param> and <param>high</param>, inclusive. * * @param low * @param num * @param high * @return boolean true if <param>num</param> between <param>low</param> and <param>high</param>, inclusive, else * false. */ private static boolean isNumBetween(long low, long num, long high) { return num >= low && num <= high; } }