Source for file ExtendsValidatorRule.class.php

<?php
 
require_once(HARMONI."utilities/FieldSetValidator/rules/ValidatorRule.interface.php");
 
/**
 * The ExtendsValidatorRule checks if a given object is extends a given class.
 *
 * @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: ExtendsValidatorRule.class.php,v 1.5 2007/09/04 20:25:55 adamfranco Exp $
 */ 
class ExtendsValidatorRule
    extends ValidatorRuleInterface 
{
 
    /**
     * The name of the parent class.
     * The name of the parent class. Will check whether the given object extends
     * this parent class.
     * @access private
     * @var mixed $_regex 
     */ 
    var $_parentClassName;
 
    /**
     * The constructor.
     * @access public
     * @param string $parentClassName The name of the parent class. Will check
     *  whether the given object extends this parent class.
     * @return void 
     ***/
    function ExtendsValidatorRule($parentClassName) {
        $this->_parentClassName = strtolower($parentClassName);        
    }
    
 
    /**
     * Checks that the given object extends a specified class.
     * Checks that the given object extends a specified class.
     * @param mixed $val The value to check.
     * @access public
     * @return boolean TRUE, if the object extends the class; FALSE if it is not.
     ***/
    function check( $val ) {
        return is_a($val, $this->_parentClassName);
    }
    
    /**
     * 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 string $parentClassName The name of the parent class. Will check
     *  whether the given object extends this parent class.
     * @return object ValidatorRule 
     * @access public
     * @static
     * @since 3/28/05
     */
    function getRule ($parentClassName) {
        if (!isset($GLOBALS['validator_rules']) || !is_array($GLOBALS['validator_rules']))
            $GLOBALS['validator_rules'] = array();
        
        $class = __CLASS__;
        $ruleKey = $class."(".strtolower($parentClassName).")";
        
        if (!isset($GLOBALS['validator_rules'][$ruleKey]))
            $GLOBALS['validator_rules'][$ruleKey] = new $class($parentClassName);
        
        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->_parentClassName.")";
    }
}
 
?>