Basic html element oop example

example.php

<?php


interface renderable {
  function render();
}

abstract class Html implements renderable{
  protected $name;
  protected $attributes = [];
  protected $content;

  public function render() {
    $result = '';
    $result .= '<' . $this->name;
    $attributes = [];

    if (count($this->attributes)) {
      $result .= ' ';
    }

    foreach ($this->attributes as $key => $value) {
      $attributes[] = $key . '="' . $value . '"';
    }
    $result .= join(' ', $attributes);
    $result .= '>';

    if ($this->content !== NULL) {
      $result .= $this->content . '</' . $this->name . '>';
    }
    return $result;
  }
}

class Text implements renderable{
  private $text;

  function __construct($text) {
    $this->text = $text;
  }

  function render() {
    return $this->text;
  }
}

abstract class HtmlContainer extends Html {
  protected $children = [];

  public function addChild(renderable $element) {
    $this->children[] = $element;
  }

  public function render() {

    $childHtml = [];
    foreach ($this->children as $child) {
      $childHtml[] = $child->render();
    }

    $this->content = join('', $childHtml);

    return parent::render();
  }
}

class Image extends Html {
  function __construct($src) {
    $this->name = 'img';
    $this->attributes['src'] = $src;
  }
}

class Paragraph extends HtmlContainer {
  function __construct() {
    $this->name = 'p';
  }
}

class Div extends HtmlContainer {
  function __construct() {
    $this->name = 'div';
  }
}

class Heading extends Html {
  function __construct($level, $text) {
    $this->name = 'h' . $level;
    $this->content = $text;
  }
}


class Boek implements renderable{
  protected $name;
  protected $image;

  function __construct($name, $image) {
    $this->name = $name;
    $this->image = $image;
  }

  function render() {
    $output = new Div();
    $output->addChild(new Heading(2, $this->name));
    $output->addChild(new Image($this->image));
    return $output->render();
  }
}


$boeken = new Div();

$boeken->addChild(new Boek('De pizzamaffia', 'http://www.bruuttaal.nl/Jeugdliteratuur/Bronnen/Pizzamaffia.JPG'));
$boeken->addChild(new Boek('Javascript: The good parts', 'http://t0.gstatic.com/images?q=tbn:ANd9GcTRJVMsmtzmYn0U1Vrl_uI4X0Xbct7KvYhjeqEg7QxjBGn6fZx7'));

echo $boeken->render();