Is HandlerManager really necessary?

[Matt Erwin]

Hello everyone,

My partner and I have been writing a web app following the MVP architecture laid out here: https://developers.google.com/web-toolkit/articles/mvp-architecture

As this is our first foray into web development, GWT has been incredibly helpful and useful, but forgive my questions should they sound naive.

I'm trying to figure out why the HandlerManager is even necessary. The way we currently manage our app through the AppController is to keep a stack of Presenters and push new screens onto the stack and pop them off when you're done with them.

In the Contacts example Google provides in the above link, it seems the HandlerManager does 2 things when the event is called: write a history item, go to a new presenter.

Is this really necessary? If we end up making an app with 100 screens, we'll end up having 100 Event classes and 100 EventHandler classes. Seems to me like the views and presenters should be enough, while each presenter and decide which presenters it can go to.

Thanks in advance to anyone that can either confirm my feelings or give me a reason to use the HandlerManager.

Matt