<?php
/**
 * Caching: abstract cache driver
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage base
 */

/**
 * Caching: abstract cache driver
 *
 * Abstract driver defines the interface.
 * Make sure al derived class load and store index properly!
 *
 * @version 0.1.0
 * @package WB
 * @subpackage base
 */
abstract class WBCache_Driver
{
   /**
    * cache index
    *
    * Make this index presistent!
    * @var array
    */
    protected $_index   =   array();
    
   /**
    * fetch information from index
    *
    * This will return a reference to the index!
    * 
    * @return index list
    */
    public function &getIndex()
    {
        return $this->_index;
    }
    
   /**
    * fetch cached data
    * 
    * @param string $id cache id
    * @return mixed return data or null if not cached yet
    */
    abstract public function get( $id );
   
   /**
    * store data in cache
    * 
    * @param string $id cache id
    * @return mixed return data or null if not cached yet
    */
    abstract public function set( $id, $data );

   /**
    * flush cached data
    * 
    * @param string $id cache id
    * @return bool true on success
    */
    abstract public function flush( $id );
}
?>