一、迭代器模式
- 迭代器模式，在不需要了解内部实现的前提下，遍历一个聚合对象的内部元素
- 相比传统的编程模式，迭代器模式可以隐藏遍历元素所需的操作
应用场景
遍历数据库表，拿到所有的user对象，然后用佛 foreach 循环，在循环的过程中修改某些字段的值。
实例代码：
class MySQLis{
protected $conn;
public function connect($host, $user, $pwd, $dbname){
$this->conn = mysqli_connect($host, $user, $pwd, $dbname);
}
public function query($sql){
$res =mysqli_query($this->conn, $sql);
return $res;
}
public function close(){
mysqli_close($this->conn);
}
}
class User{//数据对象模式
public $id;
public $name;
public $tell;
protected $db;
public function __construct($id){
$this->db = new MySQLis();
$this->db->connect('localhost', 'func', 'passwd', 'test');
$res = $this->db->query("select * from user where id = {$id} limit 1");
$data = $res->fetch_assoc();
$this->id = $data['id'];
}
public function __destruct(){
$this->db->query("update user set name = '{$this->name}', tell = '{$this->tell}' where id= {$this->id}");
}
}
class Factory{//工厂模式
public static function CreateAnimal($name){
}
public static function getUser($id){
$key = "user_{$id}";
$user = Register::get($key);
if (!$user) {
$user = new User($id);
Register::set($key, $user);
}
return $user;
}
}
class Register {//注册器模式
protected static $object;
public static function set($alias, $object){
self::$object[$alias] = $object;
}
public static function get($alias){
return self::$object[$alias];
}
public static function _unset($alias){
unset(self::$object[$alias]);
}
}
class AllUser implements \Iterator{
protected $ids;
protected $index;
protected $data = array();
public function __construct(){
$db = new MySQLis();
$db->connect('localhost', 'func', 'passwd', 'test');
$res = $db->query('select id from user');
$this->ids = $res->fetch_all(MYSQLI_ASSOC);
}
//返回当前索引游标指向的元素
public function current(){
$id = $this->ids[$this->index]['id'];
return Factory::getUser($id);
}
//移动当前索引游标到下一元素
public function next(){
$this->index ++;
}
//返回当前索引游标指向的键
public function key(){
return $this->index;
}
//判断当前索引游标指向的元素是否有效
public function valid(){
return $this->index < count($this->ids);
}
//重置索引游标
public function rewind(){
$this->index = 0;
}
}
$user = new AllUser();
foreach ($user as $key => $value) {
print_r($value);
｝二、代理模式
在客户端与实体之间建立一个代理对象(proxy)，客户端对实体进行操作全部委派代理对象，隐藏实体的具体实现细节；
proxy还可以与业务代码分离，部署到另外的服务器。业务代码中通过RPC来委派任务
数据库主从，通过代理设置主从读写设置。
示例代码：
class MySQLis{
protected $conn;
public function connect($host, $user, $pwd, $dbname){
$this->conn = mysqli_connect($host, $user, $pwd, $dbname);
}
public function query($sql){
$res =mysqli_query($this->conn, $sql);
return $res;
}
public function close(){
mysqli_close($this->conn);
}
}
class Proxy implements IUserProxy{
public function getUserName($id){
$db = new MySQLis();
$db->connect('localhost', 'func', 'passwd', 'test');
$db->query('select * from user where id='.$id);
}
public function setUserName($id, $name){
$db = new MySQLis();
$db->connect('localhost', 'func', 'passwd', 'test');
$db->query("update user set name= '{$name}' where id= {$id}");
}
}
interface IUserProxy{
public function getUserName($id);
public function setUserName($id, $name);
}
$proxy = new Proxy();
$proxy->getUserName(1);
$proxy->setUserName(1, 'admin');评论
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