Source for file ValidatorRule.interface.php

<?php
 
/**
 * the ValidatorRuleInterface defines the methods required by any ValidatorRule
 *
 * @package harmoni.utilities.fieldsetvalidator.rules
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: ValidatorRule.interface.php,v 1.6 2007/09/04 20:25:55 adamfranco Exp $
 */ 
class ValidatorRuleInterface{
    /**
     * checks a given value against the rule contained within the class
     * @param mixed $val the value to check against the rule
     * @access public
     * @return boolean true if the check succeeds, false if it (guess...) fails.
     ***/
    function check( $val ) {
        die ("Method <b>".__FUNCTION__."()</b> declared in interface<b> ".__CLASS__."</b> has not been overloaded in a child class."); 
    }
    
    /**
     * This is a static method to return an already-created instance of a validator
     * rule. There are at most about a hundred unique rule objects in use durring
     * any given execution cycle, but rule objects are instantiated hundreds of
     * thousands of times.
     *
     * This method follows a modified Singleton pattern
     * 
     * @return object ValidatorRule 
     * @access public
     * @static
     * @since 3/28/05
     */
    function getRule () {
        // Because there is no way in PHP to get the class name of the descendent
        // class on which this method is called, this method must be implemented
        // in each descendent class.
        die ("Method <b>".__FUNCTION__."()</b> declared in interface<b> ".__CLASS__."</b> has not been overloaded in a child class."); 
 
        if (!isset($GLOBALS['validator_rules']) || !is_array($GLOBALS['validator_rules']))
            $GLOBALS['validator_rules'] = array();
        
        $class = __CLASS__;
        if (!isset($GLOBALS['validator_rules'][$class]))
            $GLOBALS['validator_rules'][$class] = new $class;
        
        return $GLOBALS['validator_rules'][$class];
    }
    
    /**
     * Return a key that can be used to identify this Rule for caching purposes.
     * If this rule takes no arguments, the class name should be sufficient.
     * otherwise, append the arguments.
     *
     * This method should only be called by ValidatorRules.
     * 
     * @return string 
     * @access protected
     * @since 3/29/05
     */
    function getRuleKey () {
        return get_class($this);
    }
}
 
?>