primefaces: DataTable: lazy loading pagination error

I’ve detected an issue related to pagination when using lazy loading in datatable. The problem is the following: starting by the example of showcase: http://www.primefaces.org/showcase/ui/data/datatable/lazy.xhtml, if we add a button to delete the records one by one, if you are for instance in page 2, when all record of this page have been deleted, the pagination “brokes” and displays page 1 with empty data.

Assume that the button “Delete” calls a method called “deleteCar(Car car)” which deletes the car object from the list (or directly from database), and then update the datatable, firing again the load() method from LazyDatamodel.

<p:dataTable var="car" value="#{dtLazyView.lazyModel}" paginator="true" rows="10"
                 paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}"
                 rowsPerPageTemplate="5,10,15" selectionMode="single" selection="#{dtLazyView.selectedCar}" id="carTable" lazy="true">
        <p:ajax event="rowSelect" listener="#{dtLazyView.onRowSelect}" update=":form:carDetail" oncomplete="PF('carDialog').show()" />
        <p:column headerText="Id" sortBy="#{car.id}" filterBy="#{car.id}">
            <h:outputText value="#{car.id}" />
        </p:column>
        <p:column headerText="Year" sortBy="#{car.year}" filterBy="#{car.year}">
            <h:outputText value="#{car.year}" />
        </p:column>
        <p:column headerText="Brand" sortBy="#{car.brand}" filterBy="#{car.brand}">
            <h:outputText value="#{car.brand}" />
        </p:column>
        <p:column headerText="Color" sortBy="#{car.color}" filterBy="#{car.color}">
            <h:outputText value="#{car.color}" />
        </p:column>
<p:column headerText="Color" sortBy="#{car.color}" filterBy="#{car.color}">
            <p:commandButton value="Delete" action="#{dtLazyView.deleteCar(car)}" update="carTable">
</p:commandButton>
        </p:column>
    </p:dataTable>

In the example, an IndexOutOfBoundsException will be also thrown, when deleting the last record of page 2, variable “first” will pass a value of 10 (assuming rows per page is 10) and a subList from 10 to 10-1…

About this issue

Original URL
State: closed
Created 8 years ago
Reactions: 2
Comments: 36 (36 by maintainers)

Commits related to this issue

#1921 Integrationtest for DataTable: lazy loading pagination error — committed to christophs78/primefaces by christophs78 3 years ago
#1921 Integrationtest for DataTable: lazy loading pagination error — committed to christophs78/primefaces by christophs78 3 years ago
#1921 fix ProgrammingLanguageLazyDataModel — committed to christophs78/primefaces by christophs78 3 years ago
#1921 working and broken impl of LazyDataModel — committed to christophs78/primefaces by christophs78 3 years ago
#1921 fix/workaround — committed to christophs78/primefaces by christophs78 3 years ago
#1921 Integrationtest for DataTable: lazy loading pagination error (#7672) * #1921 Integrationtest for DataTable: lazy loading pagination error * #1921 Integrationtest for DataTable: lazy loading ... — committed to primefaces/primefaces by christophs78 3 years ago
#1921 — committed to primefaces/primefaces by tandraschko 3 years ago
#1921 — committed to primefaces/primefaces by tandraschko 3 years ago
#1921 — committed to primefaces/primefaces by tandraschko 3 years ago
#1921 — committed to primefaces/primefaces by tandraschko 3 years ago
#1921 — committed to primefaces/primefaces by tandraschko 3 years ago
#1921 for DataView (Integrationtest) — committed to christophs78/primefaces by christophs78 3 years ago
#7690 DataView, DataList, DataGrid: align LazyDataModel usage and add DataView-integrationtest (#7689) * #1921 for DataView (Integrationtest) * Fix #7690: DataView: lazy loading pagination error ... — committed to primefaces/primefaces by christophs78 3 years ago

Most upvoted comments

Not sure if it fixes your problem but i always ´do something like this in my AbstractLazyDataModel:

`    @Override
    public List<T> load(int first, int pageSize, String sortField, SortOrder sortOrder, Map<String, Object> filters)
    {
        long rowCount = do your select count with filters included
        setRowCount(rowCount);
        
        if (rowCount  > 0 && first >= rowCount) {
            int numberOfPages = (int) Math.ceil(rowCount * 1d / pageSize);
            first = Math.max((numberOfPages - 1) * pageSize, 0);
        }

        .....

tandraschko on Jul 10, 2020

Not mandatory but to avoid another long debate, just make it abstract, and i’ll simply return getRowCount in our impls.

Rapster on Aug 8, 2021

Figured out how to break it. Integrationtest ist updated. Ready to get fixed. 😉

christophs78 on Aug 7, 2021

I’ll add a test later this week.

christophs78 on Aug 4, 2021

Ok I reproduced the issue in lazy mode (didn’t try in default mode): delete all rows of the last page the paginator updates with page 19 of 19 but no rows are displayed.

Rapster on Dec 2, 2020