[Incomplete] Memcached Element and ElementList auto version control [placeholder]

This is my 1st version, maybe I can use getMulti and setMulti refactor it (optimized ).

 

class CacheUtils {    const CACHE_MAX_VERSION = 10;    private $memcache;    private static $instance;    private function __construct() {        $this->memcache = new Memcache();        $this->memcache->connect('127.0.0.1', 11211) or die('Can not connect to memcached server.');    }    public static function getInstance() {        if(self::$instance == null) {            self::$instance = new CacheUtils();        }        return self::$instance;    }    public function addElementVersion($type) {        $key = 'Element_Version:'.$type;        $ver = $this->memcache->increment($key);        if ($ver == false) {            $ver = $this->memcache->set($key, 0);            $ver = $this->memcache->increment($key);        }        else if ($ver > self::CACHE_MAX_VERSION) {            // flush all! keep data correct            $this->memcache->flush();        }        return $ver;    }    public function getElementVersion($type) {        $key = 'Element_Version:'.$type;        return $this->memcache->get($key);    }    public function addElement($elem) {        $key = 'Element:'.$elem->type.':'.$elem->id;        $retE = $this->memcache->set($key, $elem);        $retV = $this->addElementVersion($elem->type);        return $retE && $retV;    }    public function getElement($type, $id) {        $key = 'Element:'.$type.':'.$id;        return $this->memcache->get($key);    }    public function getElementListVersion($type, $sql) {        $key = 'Element_List_Version:'.$type.':'.$sql;        return $this->memcache->get($key);    }    public function addElementList($type, $list, $sql = '') {        $keyList = 'Element_List:'.$type.':'.$sql;        $keyVersion = 'Element_List_Version:'.$type.':'.$sql;        $ver = $this->getElementVersion($type);        $retL = $this->memcache->set($keyList, $list);        $retV = $this->memcache->set($keyVersion, $ver);        return $retL && $retV;    }    public function getElementList($type, $sql = '') {        $keyList = 'Element_List:'.$type.':'.$sql;        $elementVersion = $this->getElementVersion($type);        $elementListVersion = $this->getElementListVersion($type, $sql);        if ($elementListVersion != $elementVersion)            return false;        else            return $this->memcache->get($keyList);    }}

 

Test Case:

 

<?phprequire_once 'PHPUnit/Framework.php';require_once dirname(__FILE__).'/../CacheUtils.php';class Person {    public $id;    public $name;    public $age;    public $createTime;    public $type;    function __construct($id, $name, $age) {        $this->id = $id;        $this->name = $name;        $this->age = $age;        $this->type = get_class($this);        $this->createTime = time();    }}/** * Test class for CacheFacade. * Generated by PHPUnit on 2010-03-28 at 04:07:43. */class CacheUtilsTest extends PHPUnit_Framework_TestCase {    /**     * testAddElement     */    public function testAddAndGetElement() {        $cacheUtils = CacheUtils::getInstance();        $person = new Person(101,'Linx', 29);        $this->assertEquals(true, $cacheUtils->addElement($person));        $personGet = $cacheUtils->getElement('Person', 101);        $this->assertEquals('Linx', $personGet->name);        var_dump($personGet);    }    public function testAddAndGetElementList() {        $cacheUtils = CacheUtils::getInstance();        $person1 = new Person(101,'Linx1', 29);        $person2 = new Person(102,'Linx2', 30);        $list = array($person1, $person2);        $this->assertEquals(true, $cacheUtils->addElementList('Person', $list));        $listGet = $cacheUtils->getElementList('Person');        $this->assertEquals(2, count($listGet));        $this->assertEquals('Linx1', $listGet[0]->name);        var_dump($listGet);    }    public function testAddAndGetElementListExpired() {        $cacheUtils = CacheUtils::getInstance();        $person1 = new Person(101,'Linx1', 29);        $person2 = new Person(102,'Linx2', 30);        $list = array($person1, $person2);        $this->assertEquals(true, $cacheUtils->addElementList('Person', $list));        // Person v2        $this->assertEquals(true, $cacheUtils->addElement($person1));        // v1 is expired        $listGet = $cacheUtils->getElementList('Person');        $this->assertEquals(false, $listGet);        var_dump($listGet);    }}?>