Source for file Boolean.class.php

<?php
 
require_once(dirname(__FILE__)."/../Objects/SObject.class.php");
 
 
/**
 * A simple Boolean data type.
 *
 * @package harmoni.primitives
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: Boolean.class.php,v 1.10 2007/09/04 20:25:28 adamfranco Exp $
 */
class Boolean 
    extends SObject
{
    
    var $_bool;
    
/*******************************************************
 * Class Methods - Virtual Constructors
 *********************************************************/
 
 
    /**
     * Instantiates a new Boolean object with the passed value.
     * @param string $value 
     * @return ref object
     * @access public
     * @static
     */
    function withValue($value) {
        $temp = new Boolean($value);
        return $temp;
    }
 
    
    /**
     * Instantiates a new Boolean object from a known string
     * 
     * @param string $aString true(case insensitive) is true if not, it's false
     * @return ref object
     * @access public
     * @since 3/14/06
     */
    function fromString ($aString) {
        $temp = new Boolean(((strtolower($aString) == "true")?true:false));
        return $temp;
    }
    
    /**
     * Instantiates a new Boolean object with the value, false.
     * 
     * @return object Boolean 
     * @access public
     * @since 8/11/05
     * @static
     */
    function false () {
        $temp = new Boolean(false);
        return $temp;
    }
    
    /**
     * Instantiates a new Boolean object with the value, true.
     * 
     * @return object Boolean 
     * @access public
     * @since 8/11/05
     * @static
     */
    function true () {
        $temp = new Boolean(true);
        return $temp;
    }
 
/*******************************************************
 * Instance Methods
 *********************************************************/
 
 
    function Boolean($value=true) {
        $this->_bool = (bool) $value;
    }
    
    /**
     * Returns the boolean value.
     * @access public
     * @return boolean 
     */
    function value()
    {
        return $this->_bool;
    }
    
    /**
      * Answer a String whose characters are a description of the receiver.
      * Override this method as needed to provide a better representation
      * 
      * @return string 
      * @access public
      * @since 7/11/05
      */
     function printableString () {
        return $this->_bool?"true":"false";
    }
    
    /**
      * Answer whether the receiver and the argument are the same.
      * If = is redefined in any subclass, consider also redefining the
     * message hash.
      * 
      * @param object $anObject 
      * @return boolean 
      * @access public
      * @since 7/11/05
      */
     function isEqualTo ( $anObject ) {
         if (!method_exists($anObject, 'value'))
             return false;
             
        return ($this->_bool===$anObject->value())?true:false;
    }
    
    /**
     * Answer true if this object represents a 'true' value, false otherwise.
     * 
     * @return boolean 
     * @access public
     * @since 9/29/05
     */
    function isTrue () {
        return $this->_bool;
    }
    
    /**
     * Answer true if this object represents a 'false' value, false otherwise.
     * 
     * @return boolean 
     * @access public
     * @since 9/29/05
     */
    function isFalse () {
        return $this->_bool?false:true;
    }
}