Rune Kaagaard

<?php

error_reporting(E_ALL|E_STRICT);

class RuneSubject implements SplSubject {
    private $_observers;

    public function __construct() {
        $this->_observers = new SplObjectStorage();
    }

    public function attach(SplObserver $object) {
        $this->_observers->attach($object);
    }

    public function detach(SplObserver $object) {
        $this->_observers->detach($object);
    }

    public function notify() {
        foreach ($this->_observers as $o) $o->update($this);
    }
}
class RuneAccount extends RuneSubject  {
    public $status;

    public function __construct() {
        parent::__construct();
        $this->attach(new RuneLogger());
        $this->attach(new RuneMailer());
    }

    public function save() {
        $this->notify();
    }
}

class RuneLogger implements SplObserver {
    public function update(SplSubject $subject) {
        //Update status in log table
        echo "Updating status in log table.\n";
    }
}

class RuneMailer implements SplObserver {
    public function update(SplSubject $subject) {
        switch (get_class($subject)) {
            case "RuneAccount":
                if ($subject->status == "Expired") {
                    //send email: "account expired"
                    echo "Sending account expired email.\n";
                }
        }
    }
}

$account = new RuneAccount();
$account->status = "Expired";
$account->save();

/**
 * Outputs:
 *   Updating status in log table
 *   Sending account expired email.
 */