service-locator-example1.php

<?php
namespace Acme\Services;

class ServiceLocator {
    private $services = array();

    public function set($name, $instance)
    {
        $this->services[$name] = $instance;
    }
    
    public function get($name)
    {
        return $this->services[$name];
    }
}

class SomeDatabaseMapper
{
    public function findAll($table)
    {
        //Find all entries in some way
    }
}

class MovieFinder
{
    private $container;

    public function __construct(ServiceLocator $container) {
        $this->container = $container;
    }

    public function findAll()
    {
        return $this->container->get("db")->findAll("movies");
    }
}

class MovieLister
{
    private $container;

    public function __construct(ServiceLocator $container) {
        $this->container = $container;
    }

    public function list()
    {   
        return $this->container->get("movie_finder")->findAll();
    }
}

$container = new ServiceLocator();
$container->set("db", new SomeDatabaseMapper());
$container->set("movie_finder", new MovieFinder($container));
$container->set("movie_lister", new MovieLister($container));

$movieList = $container->get("movie_lister")->list();

Three words about it...

Avoid... avoid... avoid!