<?php

require __DIR__.'/vendor/autoload.php';

use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;

class Before
{
    public function __construct(LoggerInterface $logger = null)
    {
        $this->logger = $logger;
    }

    public function doSomething()
    {
        if ($this->logger) {
            $this->logger->debug('we are doing something.');
        }

        $a = 1;
        $b = 1;
        $c = $a + $b;

        if ($this->logger) {
            $this->logger->debug('we have done something.');
        }

        return $c;
    }
}

class After
{
    public function __construct(LoggerInterface $logger = null)
    {
        $this->logger = $logger ?: new NullLogger;
    }

    public function doSomething()
    {
        $this->logger->debug('we are doing something.');

        $a = 1;
        $b = 1;
        $c = $a + $b;

        $this->logger->debug('we have done something.');

        return $c;
    }
}

$logger = new NullLogger;

for ($i=0; $i < 1000; $i++) {
    // $s = new Before();
    $s = new After();
    $s->doSomething();
}

<?php

require_once __DIR__.'/vendor/autoload.php';

class Foo
{
    public $logger = null;

    public function __construct($logger = null)
    {
        $this->logger = $logger;
    }

    public function call()
    {
        if (null !== $this->logger) {
            $this->logger->notice('hello');
        }
    }
}

class Bar
{
    public $logger = null;

    public function __construct($logger = null)
    {
        $this->logger = $logger ?: new \Psr\Log\NullLogger();
    }

    public function call()
    {
        $this->logger->notice('hello');
    }
}

$name = isset($argv[1]) ? $argv[1] : null;

switch ($name) {
    case 'foo':
        $foo = new Foo();
        break;
    case 'fool':
        $foo = new Foo(new \Monolog\Logger('foo'));
        break;
    case 'bar':
        $foo = new Bar();
        break;
    case 'barl':
        $foo = new Bar(new \Monolog\Logger('foo'));
        break;
    default:
        throw new \InvalidArgumentException('Accepted arguments: foo|fool|bar|barl');

}

for ($i = 0; $i < 100000; $i++) {
    $foo->call();
}