class-dependency-cache.php

<?php
class FooBar {
    private $id = 1;

    private $user;

    public function getUser() {
        if (!$this->user instanceof User) { // Only load it if we don’t have it.
            $this->user = DB::load(‘User’, $this->id); // Cache the result in the object.
        }
       
        return $this->user; // Return cache (new/old who cares).
    }

    function __sleep() {
        return array(‘id’); // Exclude the internal User object from serealization (may become stale, let DB handle single object caching).

    }

    function __wakeup() {
        $this->getUser(); // Throw result, but primes the cached User object.
    }
}
?>