symfony/src/Symfony/Component/DependencyInjection/README.md

DependencyInjection Component

DependencyInjection manages your services via a robust and flexible Dependency Injection Container.

Here is a simple example that shows how to register services and parameters:

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Reference;

$sc = new ContainerBuilder();
$sc
    ->register('foo', '%foo.class%')
    ->addArgument(new Reference('bar'))
;
$sc->setParameter('foo.class', 'Foo');

$sc->get('foo');

Method Calls (Setter Injection):

$sc = new ContainerBuilder();

$sc
    ->register('bar', '%bar.class%')
    ->addMethodCall('setFoo', array(new Reference('foo')))
;
$sc->setParameter('bar.class', 'Bar');

$sc->get('bar');

Factory Class:

If your service is retrieved by calling a static method:

$sc = new ContainerBuilder();

$sc
    ->register('bar', '%bar.class%')
    ->setFactoryClass('%bar.class%')
    ->setFactoryMethod('getInstance')
    ->addArgument('Aarrg!!!')
;
$sc->setParameter('bar.class', 'Bar');

$sc->get('bar');

File Include:

For some services, especially those that are difficult or impossible to autoload, you may need the container to include a file before instantiating your class.

$sc = new ContainerBuilder();

$sc
    ->register('bar', '%bar.class%')
    ->setFile('/path/to/file')
    ->addArgument('Aarrg!!!')
;
$sc->setParameter('bar.class', 'Bar');

$sc->get('bar');

Resources

You can run the unit tests with the following command:

$ cd path/to/Symfony/Component/DependencyInjection/
$ composer.phar install
$ phpunit