装饰器模式

<?php
//装饰器模式
class BaseArt {
    protected $content;
    protected $art = null;
    
    public function __construct($content){
        $this->content = $content;
    }
    
    public function decorator(){
        return $this->content;
    }
}

//编辑文章摘要
class BianArt extends BaseArt {
    public function __construct(BaseArt $art){
        $this->art = $art;
    }
    
    public function decorator(){
        return $this->content = $this->art->decorator() . ',小编加上文章摘要';
    }
}

class SEOart extends BaseArt {
    public function __construct(BaseArt $art){
        $this->art = $art;
    }
    
    public function decorator(){
        return $this->content = $this->art->decorator() . ',SEO加上关键词';
    }
}

$b = new SEOart(new BianArt(new BaseArt('天天向上')));
echo $b->decorator();