prime faces default value in selectOneMenu - jsf

Question

i have problem with selectonemenu component
in View i have this code:
<p:selectOneMenu id="city" value="#{logisticsController.selectedTrip}" >
<f:selectItem itemValue="#{null}" itemLabel="Wybierz podroz" />
<f:selectItems value="#{logisticsController.tripList}" />
<p:ajax update="pojoPickList"
listener="#{logisticsController.handleTripChange}" />
</p:selectOneMenu>
logisticsController is SessionScoped bean and have init method:
#PostConstruct
public void init(){
SelectedTrip = null ;
}
but every time when i refresh page selectOneMenu shows old value.
i want set default value equals null, thanks for help

Answer 1

First of all, #PostConstruct annotation says to your Injection Framework (Spring or smth else) to execute this method after dependency injections are finished (http://docs.oracle.com/javaee/7/api/javax/annotation/PostConstruct.html).
Just to simplify, we can assume that this method will execute after bean creating.
So, as it's a session scoped bean - it's created only once for user session. That's why method "public void init()" isn't called on page refresh.
There is 2 simple ways how to solve your problem:
1) If it's possible - change your SessionScoped bean to a RequestScoped, after that bean will be created on every request (on every page refresh)
2) You can just add init method invoking in your xhtml page like this:
...
#{logisticsController.init()}
<p:selectOneMenu id="city" value="#{logisticsController.selectedTrip}" >
<f:selectItem itemValue="#{null}" itemLabel="Wybierz podroz" />
<f:selectItems value="#{logisticsController.tripList}" />
<p:ajax update="pojoPickList"
listener="#{logisticsController.handleTripChange}" />
</p:selectOneMenu>
...