Example for http://dron.by/post/pattern_proektirovaniya_chain_of_responsibility__tsepochka_obyazannostey__na_php.html

Chain example.php

<?php

abstract class AbstractHandler
{
    /**
     * @var AbstractHandler
     */
    protected $_next;

    /**
     * Send request by
     *
     * @param mixed $message
     */
    abstract public function sendRequest($message);

    /**
     * @param \AbstractHandler $next
     */
    public function setNext($next)
    {
        $this->_next = $next;
    }

    /**
     * @return \AbstractHandler
     */
    public function getNext()
    {
        return $this->_next;
    }
}

class ConcreteHandlerA extends AbstractHandler
{
    /**
     * @param mixed $message
     */
    public function sendRequest($message)
    {
        if ($message == 1) {
            echo __CLASS__ . "process this message";
        }
        else {
            if ($this->getNext()) {
                $this->getNext()->sendRequest($message);
            }
        }
    }

}

class ConcreteHandlerB extends AbstractHandler
{
    /**
     * @param mixed $message
     */
    public function sendRequest($message)
    {
        if ($message == 2) {
            echo __CLASS__ . "process this message";
        }
        else {
            if ($this->getNext()) {
                $this->getNext()->sendRequest($message);
            }
        }
    }

}

$handler = new ConcreteHandlerA();
$handler->setNext(new ConcreteHandlerB());

$handler->sendRequest(1);
$handler->sendRequest(2);