Convert query string parameter to entity - jsf

Question

I'm trying to do some of the most basic scenario i think.
On starting page there is a list of categories from database and after i click on category there should be a page with some details about that category (maybe print it name and some product etc.)
I was trying to do what BalusC did on ther blog post
I'm using java-ee-7, glasfish 4.1, hibernate 4.3.5
in index.xhtml i make link to category with parameter:
<h:link outcome="category.xhtml" value="#{category.name}">
<f:param name="categoryId" value="#{category.id}"/>
</h:link>
Categories are printed just fine with query string categoryId parameter.
Then on category.xhtml i have:
<f:metadata>
<f:viewParam name="categoryId"
value="#{categoryController.category}"
converter="#{categoryConverter}" />
</f:metadata>
<h:body>
Category name:
<h:outputText value="#{categoryController.category.name}" />
<!-- this one prints nothing -->
</h:body>
CategoryController code looks like this:
#Named
#RequestScoped
public class CategoryController {
private Category category;
public void setCategory(Category category) {
this.category = category;
}
public Category getCategory() {
return category;
}
}
and the converter looks like this:
#Named
#RequestScoped
public class CategoryConverter implements Converter {
#Inject
private CategoryRepository categoryRepository;
#Override
public Object getAsObject(FacesContext facesContext, UIComponent uiComponent, String s) {
return categoryRepository.find(Integer.parseInt(s));
}
#Override
public String getAsString(FacesContext facesContext, UIComponent uiComponent, Object o) {
if (o == null || !(o instanceof Category)) {
return null;
}
return ((Category) o).getId().toString();
}
}
Making some test only getAsString method is invoked, but i think there should be getAsObject instead.
Statement <h:outputText value="#{categoryController.category.name}" /> prints nothing (it is probably null).
How can i have Category entity in category.xhtml page?
--
To make it clear, i make it work with somethink like
<h:commandButton action="#{categoryController.showCategory(category)}" />
but this generate http post and i want to have simple get request. For me it would be just ridiculous that it would be only accessible through post.
In case something is missing, i make it accessible through github with stripped unnecessary code here: https://github.com/Yavin/jsf-entity-convert