Symfony
sponsored by SensioLabs
Menu
  • About
  • Documentation
  • Screencasts
  • Cloud
  • Certification
  • Community
  • Businesses
  • News
  • Download
  1. Home
  2. Documentation
  3. Event Dispatcher
  4. The Immutable Event Dispatcher
  • Documentation
  • Book
  • Reference
  • Bundles
  • Cloud
Search by Algolia

The Immutable Event Dispatcher

Edit this page

The Immutable Event Dispatcher

The ImmutableEventDispatcher is a locked or frozen event dispatcher. The dispatcher cannot register new listeners or subscribers.

The ImmutableEventDispatcher takes another event dispatcher with all the listeners and subscribers. The immutable dispatcher is just a proxy of this original dispatcher.

To use it, first create a normal EventDispatcher dispatcher and register some listeners or subscribers:

1
2
3
4
5
6
7
8
use Symfony\Component\EventDispatcher\EventDispatcher;

$dispatcher = new EventDispatcher();
$dispatcher->addListener('foo.action', function ($event) {
    // ...
});

// ...

Now, inject that into an ImmutableEventDispatcher:

1
2
3
4
use Symfony\Component\EventDispatcher\ImmutableEventDispatcher;
// ...

$immutableDispatcher = new ImmutableEventDispatcher($dispatcher);

You'll need to use this new dispatcher in your project.

If you are trying to execute one of the methods which modifies the dispatcher (e.g. addListener()), a BadMethodCallException is thrown.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.
We stand with Ukraine.
Version:

Symfony 6.2 is backed by

Symfony 6.2 is backed by

Show your Symfony expertise

Show your Symfony expertise

Symfony Code Performance Profiling

Symfony Code Performance Profiling

↓ Our footer now uses the colors of the Ukrainian flag because Symfony stands with the people of Ukraine.

Avatar of CJDennis, a Symfony contributor

Thanks CJDennis for being a Symfony contributor

2 commits • 34 lines changed

View all contributors that help us make Symfony

Become a Symfony contributor

Be an active part of the community and contribute ideas, code and bug fixes. Both experts and newcomers are welcome.

Learn how to contribute

Symfony™ is a trademark of Symfony SAS. All rights reserved.

  • What is Symfony?
    • Symfony at a Glance
    • Symfony Components
    • Case Studies
    • Symfony Releases
    • Security Policy
    • Logo & Screenshots
    • Trademark & Licenses
    • symfony1 Legacy
  • Learn Symfony
    • Symfony Docs
    • Symfony Book
    • Reference
    • Bundles
    • Best Practices
    • Training
    • eLearning Platform
    • Certification
  • Screencasts
    • Learn Symfony
    • Learn PHP
    • Learn JavaScript
    • Learn Drupal
    • Learn RESTful APIs
  • Community
    • SymfonyConnect
    • Support
    • How to be Involved
    • Code of Conduct
    • Events & Meetups
    • Projects using Symfony
    • Downloads Stats
    • Contributors
    • Backers
  • Blog
    • Events & Meetups
    • A week of symfony
    • Case studies
    • Cloud
    • Community
    • Conferences
    • Diversity
    • Documentation
    • Living on the edge
    • Releases
    • Security Advisories
    • SymfonyInsight
    • Twig
    • SensioLabs
  • Services
    • SensioLabs services
    • Train developers
    • Manage your project quality
    • Improve your project performance
    • Host Symfony projects
    Deployed on
Follow Symfony
Search by Algolia