<?php

namespace Prado\Data\SqlMap\DataMapper;

/**
 * TSqlMapCache class file contains FIFO, LRU, and GLOBAL cache implementations.
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Data\SqlMap\DataMapper
 */

/**
 * Least recently used cache implementation, removes
 * object that was accessed last when the cache is full.
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @package Prado\Data\SqlMap\DataMapper
 * @since 3.1
 */
class TSqlMapLruCache extends TSqlMapCache
{
	/**
	 * @return mixed Gets a cached object with the specified key.
	 */
	public function get($key)
	{
		if($this->_keyList->contains($key))
		{
			$this->_keyList->remove($key);
			$this->_keyList->add($key);
			return $this->_cache->itemAt($key);
		}
	}

	/**
	 * Stores a value identified by a key into cache.
	 * The expire and dependency parameters are ignored.
	 * @param string the key identifying the value to be cached
	 * @param mixed the value to be cached
	 */
	public function set($key, $value,$expire=0,$dependency=null)
	{
		$this->_cache->add($key, $value);
		$this->_keyList->add($key);
		if($this->_keyList->getCount() > $this->_cacheSize)
		{
			$oldestKey = $this->_keyList->removeAt(0);
			$this->_cache->remove($oldestKey);
		}
	}
}