Adding Messages as request attribute to enforce flash scope when redirect

[garcia-jj]

Closes #795

[Turini]

sounds ok to me 👍

[garcia-jj]

I need to change the code because using the own Messages class is only the way to guarantee that vmessages attribute will put into request attributes.

[Turini]

kinda ugly, but if its working... :) I'm merging here to do a release, if
someone provides a better alternative we can update it later. thanks!

[garcia-jj]

Sorry. I didn't answer before your merge. But this code not working too. My
bad, because I forgot to change forward to redirect in my test code.

We need to think in another way to use flash scope for Messages.

Ideas?

[Turini]

ops... sorry. I thought it was solved. I'll take a look on it before releasing.

[garcia-jj]

Thank you, @Turini.

To create the scenario is very simple. You must create a controller with 2 methods:

public class MyFunnyController {
    @Inject private Result result;
    @Inject private Messages messages;

    public void page0() {
        messages.add(new SimpleMessage("category", "my funny message", Severity.SUCCESS));
        result.redirectTo(this).page1();
    } 

    public void page1() {
        String str = messages.get(Severity.SUCCESS).toString();
        System.out.println(str);
        result.use(http()).body(str);
        // you can see the message representation here
    } 
}