Question

I’m using a datalist with Ajax pagination and the first page loads fine, showing 5 results. It knows I’ve got 3 pages worth of results, but when I click through to the second/third pages, I get an empty list.

My model extends LazyDataModel and the first time my page loads, I can set a breakpoint on the load() method and I can see it’s asking for results 1-5 which is great. But clicking on ‘page 2’ doesn’t result in another call to the load method (although it does result in about 3 calls to my lazyDataModel field itself (just not the load method inside it).

New to this and despite reading a lot and trying out various things, I can’t understand quite how it should work. The showcase example doesn’t seem quite ‘complete’ to me.

Here’s the most relevant bits of my code (I think). Sorry about the formatting:

@PostConstruct
public void LoadData() {
  lazyModel = new LazyDataModel<MessageboardThread>() {

  @Override
  public List<MessageboardThread> load(int first, int pageSize, String sortField, SortOrder so, Map<String, String> map) {
    List<MessageboardThread> result = new ArrayList<MessageboardThread>();

    try {
        result = mbDao.findAll(pageSize, first);
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return result;
  }
};
getLazyModel().setRowCount(mbDao.count());
getLazyModel().setPageSize(pageSize);
}    

This method DOES get executed every time I click on next/prev page
/**
* @return the lazyModel
*/
public LazyDataModel getLazyModel() {
return lazyModel;
}

And this is my xhtml file

          <p:dataList value="#{messageboardBean.lazyModel}" var="thread" id="threads"  
                paginator="true" rows="5" effectSpeed="fast"  
                paginatorTemplate="{PreviousPageLink} {CurrentPageReport} {NextPageLink} {RowsPerPageDropdown}"  
                rowsPerPageTemplate="5,10,15" type="none"
                paginatorPosition="bottom">  

                    <f:facet name="header">  
                        Conversations 
                    </f:facet>  

                    <p:column>  
                        <h:outputText value="#{thread.title}" style="margin-left:10px" />  
                        <br />  
                    </p:column>  
            </p:dataList> 

I’m stumped so really grateful for any help

PS I put a @PostContruct annotation there because it seemed to be a good place to do the setup but it could be wrong, I haven’t seen it on any other examples, but then I couldn’t get any other examples to work either.

Answer 1

Solved it. I forgot to wrap the dataList attribute in an h:form tag. It works fine now.