composite_example.php

<?php
abstract class Component {
	protected $parent = null;
	protected $children = array();
	protected $name;
	abstract function add($child);
	abstract function remove($child);
	abstract function getChildren();
	abstract function print();
}

class Tag extends Component {
	function __construct($name)    {
		$this->name = $name;
	}
	function add($child)	{
		$this->children[] = $child;
		$child->parent = $this;
	}
	function remove($child)	{
		$counter = 0;
		$exists = false;
		foreach($this->children as $item)	{
			if($item===$child)	{
				$exists = true;
				break;
			}
			$counter++;
		}
		if($exists) {
			$this->children = array_splice($this->children, $counter, 1);
		}
	}
	function getChildren()	{
		return $this->children;
	}
	function print()	{
		echo "<{$this->name}>";
		foreach($this->children as $item)	{
			$item->print();
		}
		echo "</{$this->name}>";
	}
}

$table = new Tag("table");
$tr = new Tag("tr");
$table->add($tr);
$td1 = new Tag("td");
$tr->add($td1);
$td2 = new Tag("td");
$tr->add($td2);

$table->print();
$tr->remove($td1);
$table->print();