Loader for my Content Management system

loader.php

<?php if ( !defined('BASE') ) die('No Direct Script Access');
/**
 *  Loader Class for VMS Content Management System
 *
 *  @author     Shawn Crigger <shawn@eaglewebdesigns.com>
 *  @version    1.0.5
 *  @copyright  (c) 2010 - 2012 S-Vizion Software & Eagle Web Designs
 *  @package    VisionManagementSystems
 *  @subpackage AssetLoader
 *  @since      version 3.0BE
 *  @license    DBAD <http://philsturgeon.co.uk/code/dbad-license>
 *  
 */
class Loader {

  function __construct()
  {
    
    
  }

  /**
   * Private function used in loader to check if file exists and is a actual file to load
   * 
   * @param string $file Full path to file to check for existance
   * 
   * @return boolean    True or False depending on if file exists
   */
  private function _isfile ( $file )
  {
    return ( file_exists ( $file ) && is_file ( $file ) );
  }
  
  /**
   * Function used to load model files
   * 
   * @param string $sCoreName   Model Name
   * @param mixed  $sParams     Params to Pass to Model
   * 
   * @return object    Object Loaded
   */
  public function model( $sCoreName , $sParams = NULL )
  {
    $sModelFile = $sCoreName . '_model.php';
    
    if ( is_object ( $sCoreName ) === true )
      return false;
    
    if  ( $this->_isfile ( $sModelFile ) )
      include_once($sModelFile);
    else
      return false;
        
    return new $sCoreName( $sParams );
  }

  /**
   * Function used to load controller files
   * 
   * @param string $sCoreName  Controller Name
   * @param mixed  $sParams     Params to Pass to Controller
   * 
   * @return object    Object Loaded
   */
  public function controller( $sCoreName, $sParams = NULL )
  {
    $sControllerFile = $sCoreName . '_controller.php';

    if ( is_object ( $sCoreName ) === true )
      return false;
  
    if ( $this->_isfile ( $sControllerFile ) ) 
      include_once($sControllerFile);
  
    return new $sCoreName( $sParams );
  }
  
  /**
   * Function used to load Library Class files
   * 
   * @param string $sCoreName   Class Name
   * @param mixed  $sParams     Params to Pass to Model
   * 
   * @return object    Object Loaded
   */  
  public function library ( $sCoreName, $sParams = NULL )
  {  
    $sCoreFile = CLS_DIR . $sCoreName . '.class.php';

    if ( is_object ( $sCoreName ) === true )
      return false;
  
    if ( $this->_isfile ( $sCoreFile ))
      include_once($sCoreFile);
    else
      return false;
  
    return new $sCoreName( $sParams );
  }

  /**
   * Function used to load Helper files
   * 
   * @param string $sCoreName  Helper Name
   * @param mixed  $sParams     Params to Pass to Model
   * 
   * @return object    Object Loaded
   */  
  public function helper ( $sCoreName, $sParams = NULL )
  {  
    $sCoreFile = HLP_DIR . $sCoreName . '_helper.php';
    
    if ( is_array ( $sParams) )
    {      
      extract ( $sParams );
      unset ( $sParams );
    }
    
    if ( $this->_isfile ( $sCoreFile ))
      require($sCoreFile);
    else
      return false;
  }

  /**
   * Function used to load Module files
   * 
   * @param string $sCoreName   Module Name
   * @param mixed  $sParams     Params to Pass to Model
   * 
   * @return object    Object Loaded
   */  
  public function module ( $sCoreName, $sParams = NULL )
  {  
    $sCoreFile = MDS_DIR . $sCoreName . '.inc.php';
  
    if ( $this->_isfile ( $sCoreFile ))
      include_once($sCoreFile);
    else
      return false;
  }

}

?>