PHP结构型模式之代理模式

<?php
// 主题接口
interface Subject
{
    public function request();
}
// 真实主题类
class RealSubject implements Subject
{
    public function request()
    {
        echo "RealSubject handles request.\n";
    }
}
// 代理类
class Proxy implements Subject
{
    private $realSubject;
    public function __construct(RealSubject $realSubject)
    {
        $this->realSubject = $realSubject;
    }
    public function request()
    {
        if ($this->checkAccess()) {
            $this->realSubject->request();
            $this->logAccess();
        }
    }
    private function checkAccess()
    {
        echo "Proxy checks access.\n";
        return true;
    }
    private function logAccess()
    {
        echo "Proxy logs access.\n";
    }
}
// 客户端代码
$realSubject = new RealSubject();
$proxy = new Proxy($realSubject);
$proxy->request();

<?php
$realSubject = new RealSubject();
$proxy = new Proxy($realSubject);
$proxy->request();