Source for file Magnitude.class.php

<?php
/**
 * @since 5/4/05
 * @package harmoni.primitives.magnitudes
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: Magnitude.class.php,v 1.5 2007/09/04 20:25:27 adamfranco Exp $
 *
 * @link http://harmoni.sourceforge.net/
 * @author Adam Franco <adam AT adamfranco DOT com> <afranco AT middlebury DOT edu>
 */ 
 
require_once(dirname(__FILE__)."/../Objects/SObject.class.php");
 
/**
 * Magnitude has methods for dealing with linearly ordered collections.
 *
 * Subclasses represent dates, times, and numbers.
 *
 * Example for interval-testing (answers a Boolean):
 *    $seven->between($five, $ten);
 *
 * No instance-variables.
 * 
 * @since 5/4/05
 * @package harmoni.primitives.magnitudes
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: Magnitude.class.php,v 1.5 2007/09/04 20:25:27 adamfranco Exp $
 *
 * @link http://harmoni.sourceforge.net/
 * @author Adam Franco <adam AT adamfranco DOT com> <afranco AT middlebury DOT edu>
 */
class Magnitude 
    extends SObject
{
 
    /**
     * Test if this is less than aMagnitude.
     * 
     * @param object Magnitude $aMagnitude 
     * @return boolean 
     * @access public
     * @since 5/4/05
     */
    function isLessThan ( $aMagnitude ) {
        die("Method ".__FUNCTION__." in class ".__CLASS__
            ." should have been overridden by a child class.");
    }
    
    /**
     * Test if this is equal to aMagnitude.
     * 
     * @param object Magnitude $aMagnitude 
     * @return boolean 
     * @access public
     * @since 5/4/05
     */
    function isEqualTo ( $aMagnitude ) {
        die("Method ".__FUNCTION__." in class ".__CLASS__
        ." should have been overridden by a child class.");
    }
        
    /**
     * Test if this is greater than aMagnitude.
     * 
     * @param object Magnitude $aMagnitude 
     * @return boolean 
     * @access public
     * @since 5/3/05
     */
    function isGreaterThan ( $aMagnitude ) {
        return $aMagnitude->isLessThan($this);
    }
    
    /**
     * Test if this is greater than aMagnitude.
     * 
     * @param object Magnitude $aMagnitude 
     * @return boolean 
     * @access public
     * @since 5/3/05
     */
    function isLessThanOrEqualTo ( $aMagnitude ) {
        return ! $this->isGreaterThan($aMagnitude);
    }
    
    /**
     * Test if this is greater than aMagnitude.
     * 
     * @param object Magnitude $aMagnitude 
     * @return boolean 
     * @access public
     * @since 5/3/05
     */
    function isGreaterThanOrEqualTo ( $aMagnitude ) {
        return ! $this->isLessThan($aMagnitude);
    }
    
    /**
     * Answer whether the receiver is less than or equal to the argument, max,
     * and greater than or equal to the argument, min.
     * 
     * @param object Magnitude $min 
     * @param object Magnitude $max 
     * @return boolean 
     * @access public
     * @since 5/4/05
     */
    function isBetween ( $min, $max ) {
        return ($this->isGreaterThanOrEqualTo($min) && $this->isLessThanOrEqualTo($max));
    }
    
    /**
     * Answer the receiver or the argument, whichever has the greater
     * magnitude.
     * 
     * @param object Magnitude $aMagnitude 
     * @return object Magnitude 
     * @access public
     * @since 5/4/05
     */
    function max ( $aMagnitude ) {
        if ($this->isGreaterThan($aMagnitude))
            return $this;
        else
            return $aMagnitude;
    }
    
    /**
     * Answer the receiver or the argument, whichever has the lesser
     * magnitude.
     * 
     * @param object Magnitude $aMagnitude 
     * @return object Magnitude 
     * @access public
     * @since 5/4/05
     */
    function min ( $aMagnitude ) {
        if ($this->isLessThan($aMagnitude))
            return $this;
        else
            return $aMagnitude;
    }
}
 
?>