How to do JPA query from view template in play

Question

I'm trying to do a JPA query from a view template but it's not working (I've verified that there are records using phpMyAdmin). I know this should normally be done through the controller and passed in via render, but this is part of building a menu which will appear on every page and I don't want to have to modify every controller to accomplish this.

What I'm currently trying is

<ul>
%{
    import models.Building;
    List<Building> buildings = Building.findAll();
}%
#{list items: buildings, as: 'building'}
    <li><a href="">${building}</a></li>
#{/list}
</ul>

but I'm getting the error The template /app/views/Networks/grid.html does not compile : unexpected token: ( referencing the line which calls findAll(). What's the right way to do this?

Answer 1

Instead of trying to do this in the page (bad practice) or add it to every Controller you should add it to one parent controller in a method annotated with @Before. This will get called on each page so you only need to do the code once.

Eg. The parent controller (aka interceptor) would look like:

public class ControllerInterceptor extends Controller {
   @Before
   public static void intercept() {
      RenderArgs.current().put("buildings", Building.findAll());
   }
}

Then each controller would add the following annotation:

@With(ControllerInterceptor.class)
public class MyController extends Controller {
...
}

And your page code would then refer to it much as you're already doing:

<ul>
    #{list buildings, as: 'building'}
    <li>#{a @Buildings.edit(building.code)}${building}#{/a}</li>
    #{/list}
</ul>

As for why your original code didn't work, I'm not sure. Possibly something to do with how the Model class is enhanced by Play?

Answer 2

Discovered how to work around it, but I'd still be interested to know what was wrong with the original code. I got it working by just doing

<ul>
    #{list items: models.Building.findAll(), as: 'building'}
    <li>#{a @Buildings.edit(building.code)}${building}#{/a}</li>
    #{/list}
</ul>