<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Exception.php 20978 2010-02-08 15:35:25Z matthew $

 */

/**

* @category   Zend

* @package    Zend

* @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

* @license    http://framework.zend.com/license/new-bsd     New BSD License

*/

class Zend_Exception extends Exception

{

    /**

     * @var null|Exception

     */

    private $_previous = null;

    /**

     * Construct the exception

     *

     * @param  string $msg

     * @param  int $code

     * @param  Exception $previous

     * @return void

     */

    public function __construct($msg = '', $code = 0, Exception $previous = null)

    {

        if (version_compare(PHP_VERSION, '5.3.0', '<')) {

            parent::__construct($msg, (int) $code);

            $this->_previous = $previous;

        } else {

            parent::__construct($msg, (int) $code, $previous);

        }

    }

    /**

     * Overloading

     *

     * For PHP < 5.3.0, provides access to the getPrevious() method.

     * 

     * @param  string $method 

     * @param  array $args 

     * @return mixed

     */

    public function __call($method, array $args)

    {

        if ('getprevious' == strtolower($method)) {

            return $this->_getPrevious();

        }

        return null;

    }

    /**

     * String representation of the exception

     *

     * @return string

     */

    public function __toString()

    {

        if (version_compare(PHP_VERSION, '5.3.0', '<')) {

            if (null !== ($e = $this->getPrevious())) {

                return $e->__toString() 

                       . "\n\nNext " 

                       . parent::__toString();

            }

        }

        return parent::__toString();

    }

    /**

     * Returns previous Exception

     *

     * @return Exception|null

     */

    protected function _getPrevious()

    {

        return $this->_previous;

    }

}