一个强大的PHP缓存类(4)

                else $this->cacheError('APC not found'); 
            break;
 
            case 'xcache':
                if (function_exists('xcache_get')) $this->cache_type = 'xcache' ;
                else $this->cacheError('Xcache not found');
            break;
 
            case 'memcache':
                if (class_exists('Memcache')) $this->init_memcache();
                else $this->cacheError('memcache not found');
            break;
            
            case 'filecache':
                if (class_exists('fileCache'))$this->init_filecache();
                else $this->cacheError('fileCache not found');
            break;
            
            case 'auto'://try to auto select a cache system
                if (function_exists('eaccelerator_get'))    $this->cache_type = 'eaccelerator';                                      
                elseif (function_exists('apc_fetch'))       $this->cache_type = 'apc' ;                                    
                elseif (function_exists('xcache_get'))      $this->cache_type = 'xcache' ;                                       
                elseif (class_exists('Memcache'))           $this->init_memcache();
                elseif (class_exists('fileCache'))          $this->init_filecache();
                else $this->cacheError('not any compatible cache was found');
            break;
            
            default://not any cache selected or wrong one selected
                if (isset($type)) $msg='Unrecognized cache type selected <b>'.$type.'</b>';
                else $msg='Not any cache type selected';
                $this->cacheError($msg);    
            break;
        }
    }  
        
    private function init_memcache(){//get instance of the memcache class