JSF: How to refresh a page after download

Question

I have a commandButton that will invoke a function to download a file (standard stuffs like InputStream, BufferedOutputStream ...) After download success, at the end of the function, I change some values of the current object and persist it into database. All of these work correctly. Now when file is done downloading, the content of the page is not updated. I have to hit refresh for me to see updated content. Please help. Below are the basic structure of my code

document: Managed Bean
getDrawings(): method return a list of Drawing (entity class)
CheckedOutBy: attribute of Entity Drawing

<p:dataTable id="drawing_table" value="#{document.drawings}" var="item" >                            
    <p:column>
        <f:facet name="header">
              <h:outputText value="CheckedOutBy"/>
        </f:facet>
        <h:outputText value="#{item.checkedOutBy}"/>
        ...
</p:dataTable>
<p:commandButton ajax="false" action="#{document.Download}" value="Download" />

Inside my Managed Bean

public void Download(){
    Drawing drawing = getCurrentDrawing();
    //Download drawing
    drawing.setCheckedOutBy("Some Text");
    sBean.merge(drawing);  //Update "Some Text" into CheckedOutBy field
}

Answer 1

You could use the update attribute of the p:commandButton component to re-render the area that you intend to refresh after download, in this case your "drawing_table".

<p:commandButton update="drawing_table" action="#{document.Download}" value="Download" />

Answer 2

You'd basically like to let the client fire two requests. One to retrieve the download and other to refresh the new page. They cannot be done in a single HTTP request. Since the download needs to be taken place synchronously and there's no way to hook on complete of the download from the client side on, there are no clean JSF/JS/Ajax ways to update a component on complete of the download.

Your best JSF-bet with help of PrimeFaces is <p:poll>

<h:outputText id="checkedOutBy" value="#{item.checkedOutBy}"/>
...
<p:poll id="poll" interval="5" update="checkedOutBy" />

or <p:push>

<p:push onpublish="javaScriptFunctionWhichUpdatesCheckedOutBy" />  

Polling is easy, but I can imagine that it adds unnecessary overhead. You cannot start it using standard JSF/PrimeFaces components when the synchronous download starts. But you can stop it to let it do a self-check on the rendered attribute. Pushing is technically the best solution, but tougher to get started with. PrimeFaces explains its use however nicely in chapter 6 of the User Guide.