lexik/LexikWorkflowBundle — pull request #1 by jeremyb (2013-05-25 08:35:49+00:00)
Title: Add event dispatcher to step validations

According to steps actions executed through event dispatcher, this new step validations use same approach and introduce a `ViolationList` object to manage validation errors.

To validate a step can be reached, you just need to listen the `..access_validation event`.

Example:
```php
$dispatcher->addListener('post_publication.published.access_validation', function(StepAccessValidationEvent $event) {
if ( ! $event->getModel()->canBePublished()) {
$event->addViolation('error message');
}
}
```