[PHP知识库]php注册表，利用抽象基类，在子类实现功能，添加和获取，即可以是字符也可以是对象

<?php
abstract class Registry{
	abstract protected function set($key,$value);
	abstract protected function get($key);
}
class RequestRegistry extends Registry{
	private static $instance;
	private $values=array();
	static function instance(){
		if(!isset(self::$instance)){
			self::$instance=new self();
		}
		return self::$instance;
	}
	protected function set($key,$value){
		$this->values[$key]=$value;
	}
	 protected function get($key){
		return $this->values[$key];
	}
	function getAaa(){
		return self::instance()->get('Aaa');
	}
	function setAaa($aaa){
		self::instance()->set("Aaa",$aaa);
	}
}
class SessionRegistry extends Registry{
	private static $instance;
	private $values=array();
	static function instance(){
		if(!isset(self::$instance)){
			self::$instance=new self();
		}
		return self::$instance;
	}
	protected function set($key,$val){
		$this->values[$key]=$val;
	}
	protected function get($key){
		return $this->values[$key];
	}
	function getBbb($key){
		return self::instance()->get($key);
	}
	function setBbb($key,$val){
		self::instance()->set($key,$val);
	}
}
class reg{}

$re=SessionRegistry::instance();
$re->setBbb('Bbb',new reg());
print_r($re->getBbb('Bbb'));
$ss=RequestRegistry::instance();
$ss->setAaa('aaa');
echo $ss->getAaa('Aaa');
?>