标签：creat 委托模式 getname const struct private sharp code protect
通过分配或委托到其他对象,去除核心对象中的判决或复杂功能,动态添加新功能.
class A
{
public function song($songList)
{
foreach($songList as $val) {
echo $val . ‘.mp3‘;
}
}
}
class B
{
public function song($songList)
{
foreach($songList as $val) {
echo $val . ‘.wav‘;
}
}
}
class Delegate
{
private $obj;
private $songList = array();
public function __construct()
{
}
public function setDelegate($type)
{
$this->obj = new $type();
}
public function addSong($name)
{
$this->songList[] = $name;
}
public function song()
{
$this->obj->song($this->songList);
}
}
// 调用
$delegate = new Delegate();
$delegate->setDelegate(‘A‘);
$delegate->addSong(‘rolling in the deep‘);
$delegate->song();
特点:
每个委托的对象都拥有一个相同的public方法名.
动态创建委托对象.
委托模式下,委托对象是依据被委托者Delegate中不同的数据类型,来对数据做处理.数据还是Delegate中的,只有这样子,才能叫委托.这也是他区别工厂模式的一个重要特点.
构建的对象不必自身包含逻辑,而是根据需要利用其它对象中的算法.
我们为类的输出数据,同时提供json和xml格式,至于使用那么格式由外部调用者决定.
class User
{
private $uid, $name;
protected $strategy;
public function __construct($uid, $name)
{
$this->uid = $uid;
$this->name = $name;
}
public function getUid()
{
return $this->uid;
}
public function getName()
{
return $this->name;
}
// 设置策略
public function setStrategy($obj)
{
$this->strategy = $obj;
}
public function get()
{
return $this->strategy->get($this);
}
}
class JsonStrategy
{
public function get(User $user)
{
return json_encode(array(‘uid‘ => $user->getUid(), ‘name‘ => $user->getName()));
}
}
class XmlStrategy
{
public function get(User $user)
{
$doc = new DOMDocument();
$root = $doc->createElement(‘user‘);
$root = $doc->appendChild($root);
$elementUid = $doc->createElement(‘uid‘, $user->getUid());
$root->appendChild($elementUid);
$elementName = $doc->createElement(‘name‘, $user->getName());
$root->appendChild($elementName);
return $doc->saveXML();
}
}
$user = new User(‘1‘, ‘jack‘);
$user->setStrategy(new XmlStrategy());
echo $user->get();
$user->setStrategy(new JsonStrategy());
echo $user->get();
标签：creat 委托模式 getname const struct private sharp code protect
原文地址：http://www.cnblogs.com/itfenqing/p/7750556.html
