Template for Application class

app.php

<?php

interface Module
{
    function start();
    function stop();

    function buildContainer(Container $container);
}

class Application
{
    private $modules = [];
    private $requests = [];
    private $container;
    private $started = false;

    public function start() {
        if ($this->started === true) {
            return;
        }

        foreach ($this->modules as $module) {
            $module->start();
        }

        $this->container = $this->buildContainer(null);
        $this->started = true;
    }

    public function stop() {
        if ($this->started === false) {
            return;
        }

        foreach ($this->modules as $module) {
            $module->stop();
        }

        $this->container = null;
        $this->started = false;
    }

    public function buildContainer(Container $container) {
        $root = new CompositeContainer;

        if ($container !== null) {
            $root->add($container);
        }

        foreach ($this->modules as $module) {
            $subcontainer = $module->buildContainer($root);

            if ($subcontainer instanceof Container) {
                $root->add($subcontainer);
            }
        }

        return $root;
    }

    public function run() {
        return $this->handle(Request::fromEnviron());
    }

    public function handle(Request $request) {
        $this->started || $this->start();

        try {
            return $this->handleRequest($request);
        } catch (Exception $e) {
            if (count($this->requests) > 1) {
                throw $e;
            }

            return $this->handleException($e, $request);
        }
    }

    private function handleRequest(Request $request) {
        array_push($this->requests, $request);

        array_pop($this->requests);
    }

    private function handleException(Exception $exception, Request $request) {
    }
}