Source for file OptionalRule.class.php

<?php
 
require_once(HARMONI."utilities/FieldSetValidator/rules/ValidatorRule.interface.php");
 
/**
 * The OptionalRule allows you to have a field where a rule is applied *only* when
 * the value actually exists.
 *
 * @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: OptionalRule.class.php,v 1.7 2007/09/04 20:25:55 adamfranco Exp $
 */ 
class OptionalRule
    extends ValidatorRuleInterface
{
    /**
     * the rule to be used for the values set
     * 
     * @access private
     * @var object ValidatorRule $_rule the rule
     */ 
    var $_rule;
    
    /**
     * the constructur
     * 
     * @param object ValidatorRule $rule the rule to use for the value when set
     * @access public
     * @return void 
     ***/
    function OptionalRule( $rule ) {
        $this->_rule =  $rule;
    }
    
    
    /**
     * checks a given value to see if it's set (returns true if not), and then
     * runs the rule on it.
     * @param mixed $val the value to check
     * @access public
     * @return boolean true if the check succeeds, false if it (guess...) fails.
     ***/
    function check( $val ) {
        if (is_null($val)) 
            return true;
        
        if (isset($val) && (is_object($val) || is_array($val) || ereg("[^[:blank:]]+",$val))) {
            if (!$this->_rule->check($val))
                return false;
        }
        
        return true;
    }
    
    /**
     * 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.
     * 
     * @param object ValidatorRule $rule 
     * @return object ValidatorRule 
     * @access public
     * @static
     * @since 3/28/05
     */
    function getRule ($rule) {        
        // 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.
 
        if (!isset($GLOBALS['validator_rules']) || !is_array($GLOBALS['validator_rules']))
            $GLOBALS['validator_rules'] = array();
        
        $class = __CLASS__;
        $ruleKey = $class."(".$rule->getRuleKey().")";
        
        if (!isset($GLOBALS['validator_rules'][$ruleKey]))
            $GLOBALS['validator_rules'][$ruleKey] = new $class($rule);
        
        return $GLOBALS['validator_rules'][$ruleKey];
    }
    
    /**
     * 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($this)."(".$this->_rule->getRuleKey().")";
    }
}
 
?>