a4j:poll getting data twice

[ttsiebzehntt]

Hi,

can perhabs someone help with this issue:

https://issues.jboss.org/browse/RF-10974

With following Frontend

<a4j:poll interval="10000" data="#{testBean.pollData}" oncomplete="alert(event.data);"/>

and bean:

@ManagedBean

@SessionScoped

public class TestBean {

  int i = 0;

  public String getPollData() {

    System.out.println("getPollData()");

    return "" + i++;

  }

}

we get the following output:

1

3

5

...

Telling from the stacktraces the getter gets called in ApplyRequestValuesPhase and in RenderResponsePhase. Design or Bug?

We are using Richfaces 4.0 on Tomcat 7.

[lfryc]

Hi Martin,

you should rather use action for incrementing the counter, other attributes doesn't ensure that corresponding EL expressions won't be evaluated during request lifecycle.

However when you want to limit the incrementation one-per request, you can for example use following condition:

if (FacesContext.getCurrentInstance().getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
   i++;
}

[ttsiebzehntt]

Hi Lukáš,

thanks for the hints.

So I know how to workaround, but why is it necessary to get the data twice?

[ilya_shaikovsky]

actually Martin I think that's a valid issue. data should be used to serialize some server side object in order it to be available for further processing at client side. And I really see no reasons of performing that data population twice. Need to be checked upon 3.3.x and reviewed in order to check the reasons of such behavior.