TableState.getMultiSortMeta() on Primefaces 8 - sorting

Question

I'm upgrading from Primefaces version 7 to version 8. There is no longer a getMultiSortMeta() method in the TableState model available under PrimeFaces 8. Does anyone know how can I replace the following method and get it working in PrimeFaces 8?
public void onSort(SortEvent event) {
List<SortMeta> sortMeta = ((DataTable)
event.getComponent()).getMultiSortMeta();
channelsViewConfig.setMultiSortMeta(sortMeta);
}

Answer 1

In Primefaces 8 sortMeta is no longer a List, but uses Map<columnKey,sortMeta> to fetch the sorted collection. This collection is obtained via the attribute sortMeta rather than using sortBy;
<p:dataTable id="resultedtable"
value="#{bean.member}" var="member"
styleClass="resultedTable" paginator="true"
paginatorPosition="bottom"
pageLinks="5"
rowsPerPageTemplate="5,10"
sortMode="multiple"
sortMeta="bean.preSortOrder">
<p:column id="column1" headerText="column1" sortBy="#{member.column1}">
<h:outputText value="#{member.column1}" />
</p:column>
<p:column id="column2" headerText="column2" sortBy="#{member.column2}">
<h:outputText value="#{member.column2}" />
</p:column>
The backing bean getter for the collection would look something like this:
public Map<String, SortMeta> getPreSortOrder() {
UIViewRoot viewRoot = FacesContext.getCurrentInstance().getViewRoot();
DataTable datatable = (DataTable)
viewRoot.findComponent("resultedtable");
UIColumn sortColumn = datatable.getColumns().get(0); // Sortby - firstcolumn
String sortField = sortColumn.getClientId(); // SortField - firstcolumn
SortMeta sortMeta = new SortMeta(sortColumn.getColumnKey(),
sortField, SortOrder.ASCENDING, null
);
preSortOrder = new LinkedHashMap<String, SortMeta>();
preSortOrder.put(sortColumn.getColumnKey(), sortMeta);
return preSortOrder;
}