JSF Method is called always two times - jsf

Question

Hi I have a jsf datatabel using view scope, which allows sorting and pagination.
My problem is, that my BackingBean method for sorting is always called two times which would not be a big problem if not for sorting ascending/descending when sorting for the same row (which makes it obsolete).
Any ideas how to solve this problem? I've already read several blocks about this problem, but non was helping me in my case yet…
I also tried to change it to request scope but this just made my pagination disappear…
This is the BackingBean Methode which is only called from my facelet link:
/**
* Changing sorting of list of events by columns.
*
* #param event
* ActionListener for the sorting field.
*/
public void sort(String sortingAttribute) {
System.out.println("you called sort: " + ++x);
if (sortField.equalsIgnoreCase(sortingAttribute)) {
boolean sortAscHelp = (sortAsc) ? false : true;
sortAsc = sortAscHelp;
} else {
sortField = sortingAttribute;
}
try {
events = (eventListType.equalsIgnoreCase("search")) ?EventManager.getSearchResults(searchTitle, searchDate, searchLocation, sortField, sortAsc, offset, limit) : EventManager.getEventList(eventListType, offset, limit, sortField, sortAsc);
} catch (DatabaseException e) {
FacesContext fcxt = FacesContext.getCurrentInstance();
fcxt.addMessage(component.getClientId(),
new FacesMessage(e.toString()));
logger.error("Error while loading the sorted list of searched events.");
}
}
And here comes my facelet:
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html">
<ui:composition template="../../templates/basicTemplate.xhtml">
<ui:define name="metadata">
<f:metadata>
<f:viewParam name="title" value="#{listEventsBean.searchTitle}"/>
<f:viewParam name="location" value="#{listEventsBean.searchLocation}"/>
<f:viewParam name="date" value="#{listEventsBean.searchDate}"/>
<f:viewParam name="eventListType" value="#{listEventsBean.eventListType}"/>
<f:viewParam name="page" value="#{listEventsBean.page}"/>
<f:viewParam name="sorting" value="#{listEventsBean.sortField}"/>
<f:viewAction action="#{listEventsBean.init}"/>
</f:metadata>
</ui:define>
<ui:define name="content">
<h:form>
<p style="color:#808080; font-weight:bold; font-size:large">#{msgs.listEvents_events}</p>
<br/>
<h:outputText style="color:green" value="#{msgs.listEvents_deleted}" rendered="#{listEventsBean.deleted}"/>
<h:dataTable id="eventTable" value="#{listEventsBean.getEvents()}" var="event" binding="#{listEventsBean.component}">
<h:column>
<f:facet name="header">
<h:commandLink value="#{msgs.listEvents_title}" action="#{listEventsBean.sort('title')}">
<f:attribute name="sortField" value="title"/>
</h:commandLink>
</f:facet>
<h:outputText value="#{event.title}"/>
</h:column>
<h:column>
<f:facet name="header">
<h:commandLink value="#{msgs.listEvents_dateStart}" action="#{listEventsBean.sort('startofevent')}">
<f:attribute name="sortField" value="startOfEvent"/>
</h:commandLink>
</f:facet>
<h:outputText value="#{event.startOfEvent}">
<f:convertDateTime pattern="#{msgs.longDate}"/>
</h:outputText>
</h:column>
<h:column>
<f:facet name="header">
<h:commandLink value="#{msgs.listEvents_dateEnd}" action="#{listEventsBean.sort('endofevent')}">
<f:attribute name="sortField" value="endOfEvent"/>
</h:commandLink>
</f:facet>
<h:outputText value="#{event.endOfEvent}">
<f:convertDateTime pattern="#{msgs.longDate}"/>
</h:outputText>
</h:column>
<h:column>
<f:facet name="header">
<h:commandLink value="#{msgs.listEvents_price}" action="#{listEventsBean.sort('ticketprice')}">
</h:commandLink>
</f:facet>
<h:outputText value="#{event.ticketPrice}"/>
</h:column>
<h:column>
<f:facet name="header">
<h:outputText value="#{msgs.listEvents_action}"/>
</f:facet>
<h:button id="showDetails" value="#{msgs.listEvents_showDetails}"
outcome="showEvent">
<f:param name="eventID" value="#{event.eventID}"/>
</h:button>
<h:commandButton id="deleteEvent" value="#{msgs.listEvents_delete}"
action="#{listEventsBean.deleteEvent(event.eventID)}"
rendered="#{sessionBean.ld.systemAdmin}"
onclick="return confirm('#{msgs.listEvents_deleteMsg}')"/>
</h:column>
</h:dataTable>
<h:outputText style="color:blue" value="#{msgs.listEvents_emptyResult}" rendered="#{listEventsBean.notEmpty}"/>
<br />
<h:outputLink id="backToSearchLink" value="#{request.contextPath}/facelets/allUsers/searchEvents.xhtml" rendered="#{listEventsBean.notEmpty}">
<h:outputText value="#{msgs.listEvents_searchAgain}"/>
</h:outputLink>
<ui:repeat id="paginationEvent" var="p" value="#{listEventsBean.getPageNumbers()}">
<h:outputLink value="#{request.contextPath}/facelets/allUsers/listEvents.xhtml">
<h:outputText value="#{p.toString()}" />
<f:param name="page" value="#{p.toString()}" />
<f:param name="sorting" value="#{listEventsBean.sortField}"/>
<f:param name="eventListType" value="#{listEventsBean.eventListType}" />
</h:outputLink>
</ui:repeat>
</h:form>
</ui:define>
</ui:composition>
</ui:composition>

Answer 1

Damn it! I just found my bug!
I still had a binding attached to my dataTable (beginning of dataTable).
Because of my view scope binding causes errors. One seems to be to call my method in dataTable twice (Tanks to BalusC for this info). Deleted this and added messages by rendering them as h:outputText.
I am still open for any suggestions how to change my scope to request without loosing my pagination or how to add messages from my BackingBean differently to my application without rendering h:outputText and bindings.