<?php
namespace Component\Session;

class Session{

    private $db;

    public function __construct(array $config = array()){
        $this->db = \App::service('db');
        if(session_id() == ''){
            if($config['sess_handler']){
                session_set_save_handler(
                    array($this, "_open"),
                    array($this, "_close"),
                    array($this, "_read"),
                    array($this, "_write"),
                    array($this, "_destroy"),
                    array($this, "_gc")
                );
            }
        ini set...
        ini_set('session.gc_maxlifetime',259200);
        ini_set('session.cookie_lifetime',259200);
        ini_set...

    session_start();
    }

    public function _open(){
        return ($this->db)? true : false;
    }

    public function _close(){
        return true;
    }

    public function _read($id){
        $this->db->select_table('session')->where(array('sess_id' => $id))->limit(1)->select();
        if($this->db->STH->rowCount() > 0){
            return $this->db->fetch[0]['data'];
        }
        else{
            $access = time();
            $this->db->select_table('session')->insert(array('sess_id' => $id,'access' => $access));
        }
        return '';
    }

    public function _write($id, $data){
        $access = time();

        $this->db->select_table('session')->where(array('sess_id' => $id))->update(array('access' => $access, 'data' => $data));
        return ($this->db->STH->rowCount() > 0)? true : false;
    }

    public function _destroy($id){
        $this->db->select_table('session')->where(array('sess_id' => $id))->delete();
        return ($this->db->STH->rowCount() > 0)? true : false;
    }

    public function _gc($max){
        $old = time() - $max;

        $this->db->select_table('session')->where(array('access' => $max), 'AND', '<')->delete();
        return ($this->db->STH->rowCount() > 0)? true : false;
    }

    ...
    Other Methods
    ...
}