Datatable reRender not working with list re-ordering

[kevhender]

I have a datatable that uses an EntityQuery.resultList to populate the data, where the list is ordered by a column called "sequence". The table has drag/drop capability, so that dragging the first cell of one row to the first cell of another moves that cell above/below the destination cell.

All of the drag/drop logic works, and the entities in the list are correctly modified. However, the reRender tag on the datatable does not change the order of the list -- it only changes the data.

So, I have a table that looks like this:
1 Row 1 2 Row 2 3 Row 3

When, for instance, cell 3 is dragged onto cell 1, the table gets re-rendered as:

2 Row 1 3 Row 2 1 Row 3

Obviously, the desired result would be:
1 Row 3 2 Row 1 3 Row 2

Via debugging, I see that the resultList DOES return the list in the correct order; however, the order is not changed on the screen, just the data for each row.

The table code:

<rich:dataTable
 id="configurationList"
 var="_item"
 value="#{mainLookupList.resultList}"
 rowKeyVar="rowKey">
 <rich:column>
 <f:facet name="header">
 <h:outputLabel value="*"/>
 </f:facet>
 <a4j:outputPanel id="dropPanel">
 <h:outputText value="#{_item.sequence}" />
 <rich:dragSupport dragIndicator="indicator" dragType="item">
 ...
 </rich:dragSupport>
 <rich:dropSupport immediate="true" acceptedTypes="item"
 reRender="configurationList"
 dropListener="#{configBean.processDrop}">
 ...
 </rich:dropSupport>
 </a4j:outputPanel>
 </rich:column>
 <rich:column>
 <f:facet name="header">
 <h:outputLabel value="Name"/>
 </f:facet>
 <h:outputText value="#{_item.name}" />
 </rich:column>
</rich:dataTable>

@Name("configBean")
public class ConfigBean extends EntityHome<MyType>
{
 ...

 public void processDrop(DropEvent event)
 {
 //logic to re-order list, calling EntityHome.update() on each entity
 this.mainLookupList.refresh();
 }

 ...
}

@Name("mainLookupList")
public class ConfigurationList extends EntityQuery<MyType>
{
 public ConfigurationList()
 {
 super();
 super.setOrder("sequence");
 }

 @Override
 public String getEjbql()
 {
 return ("select c from MyType c");
 }
}

The configBean.processDrop is correctly changing the order of the list, and when I do a full page refresh after the drag/drop, the list is in the right order. Again, the problem happens with the reRender not changing the list order. Any ideas on why this is happening, and/or how to fix it? Thanks in advance.

[nbelaevski]

Hi,

Works for me on 3.3.1-snapshot:

<h:form>
 <rich:dataTable value="#{custom.data}" var="item" id="dataTable">
 <rich:column>
 <h:outputText value="#{item}" />
 <rich:dragSupport dragType="dt" dragValue="#{item}" />
 <rich:dropSupport acceptedTypes="dt" dropValue="#{item}" dropListener="#{custom.processDataDrop}"
 reRender="dataTable" immediate="true"/>
 </rich:column>
 </rich:dataTable>

 </h:form>

...
 private List<String> data = Arrays.asList("Item 1", "Item 2", "Item 3", "Item 4");

 public List<String> getData() {
 return data;
 }

 public void processDataDrop(DropEvent event) {
 String dragValue = (String) event.getDragValue();
 String dropValue = (String) event.getDropValue();

 int dragValueIdx = data.indexOf(dragValue);
 if (dragValueIdx != -1) {
 int dropValueIdx = data.indexOf(dropValue);
 if (dropValueIdx != dragValueIdx && dropValueIdx != -1) {
 data.set(dragValueIdx, dropValue);
 data.set(dropValueIdx, dragValue);
 }
 }
 }
...

a4j:log is a cool component designed to diagnose AJAX client-side issues. Please add this:

<a4j:log popup="false" />

to the page and check if there are any errors/warnings

[kevhender]

Yes, I was able to get your code to work. The issue still occurs in my code because I am persisting the changed entities in my list. Unless you feel that persisting in mid-AJAX call would be a problem, then it's more likely that my problem is Seam-related, so I will take the discussion over there... Thanks for your reply.