Decorator(装饰器模式)

<?php
class HtmlTemplate {
    // any parent class methods
}
  
class Template1 extends HtmlTemplate {
    protected $_html;
      
    public function __construct() {
        $this->_html = "<p>__text__</p>";
    }
      
    public function set($html) {
        $this->_html = $html;
    }
      
    public function render() {
        echo $this->_html;
    }
}
  
class Template2 extends HtmlTemplate {
    protected $_element;
      
    public function __construct($s) {
        $this->_element = $s;
        $this->set("<h2>" . $this->_html . "</h2>");
    }
      
    public function __call($name, $args) {
        $this->_element->$name($args[0]);
    }
}
  
class Template3 extends HtmlTemplate {
    protected $_element;
      
    public function __construct($s) {
        $this->_element = $s;
        $this->set("<u>" . $this->_html . "</u>");
    }
      
    public function __call($name, $args) {
        $this->_element->$name($args[0]);
    }
}