[EventDispatcher] no interface for event

[Miliooo]

Is there a reason why there is no interface for the event class?
https://github.com/symfony/symfony/blob/master/src/Symfony/Component/EventDispatcher/Event.php

An example

//our FooEvent class

class FooEvent extends Event implements FooEventInterface 
{  
}

This makes it impossible to do the code below

//our FooEventInterface

interface FooEventInterface extends EventInterface 
{   
}

Since there is no Event Interface the code above is not possible and without it we don't provide the public methods of the event class. Is there a good reason symfony does not provide this interface class? Should we not rely on interfaces when dispatching an event?

[stof]

An event is a value object, this is why Symfony does not define an interface for it

[Miliooo]

Thanks for the answer. Guess I'll rely on concrete classes when dispatching events. I never saw events as value objects, but it does make sense to threat them that way.

[stof]

well, the event is a value object passing the data to the listener.

Note that as of Symfony 2.4 (currently master), the event listener will receive 3 arguments: the event object, the event name and the dispatcher. In previous versions, you have to get the event name and the dispatcher from the event object (which is something we want to drop in 3.0, hence the new arguments)