ADF: how can client pick up photos from cache instead of calling servlet

Question

I have a jspx whose page definition has a viewobject exposing photo ids. I want to display those photos using af:panelForm. The panelForm has navigation buttons, first, previous, next and last. In the panelForm, i use af:objectImage component whose source attribute gets its value from an image rendering servlet to whom we pass viewobject's ImageId bound attribute. Given the passed in ImageId, servlet would then fetch the photo blob from database and streams it back to requesting client.
As I press navigation buttons to view photos, I notice photos are being cached in the client browser. However, if I keep navigating between same previously viewed photos, I was expecting the cached photos to be picked from browser cache instead of calling the servlet over and over to display the same previously viewed photos. However, cached photos dont seem to be taken advantage of and they are not picked and the servlet is always getting called. I want to not have the servlet called for previously viewed photos and instead cached photos to be used so images can be displayed faster and faster otherwise servlet will always go to database and fetch same blobs and render them which is expensive.
After lots of investigation, it seems that pressing any of the navigation buttons results in a submit of the form and on submit of the form, cached photos don't get picked. what should i do with those buttons so they don't perform submit and so that cached photos get picked without bothering the servlet ?
Please help.
<af:panelForm>
<af:panelHorizontal halign="center">
     <af:objectImage
     source="ImageRenderingServlet?imgId=#{bindings.ImageId.inputValue}"/>
</af:panelHorizontal>
<af:panelHorizontal halign="center">
<af:panelButtonBar>
     <af:commandButton
     text="first"
     actionListener="#{bindings.First.execute}"
     disabled="#{!bindings.First.enabled}"/>
     <af:commandButton
     text="previous"
     actionListener="#{bindings.Previous.execute}"
     disabled="#{!bindings.Previous.enabled}"/>
     <af:commandButton
     text="next"
     actionListener="#{bindings.Next.execute}"
     disabled="#{!bindings.Next.enabled}"/>
     <af:commandButton
     text="last"
     actionListener="#{bindings.Last.execute}"
     disabled="#{!bindings.Last.enabled}"/>
</af:panelButtonBar>
</af:panelHorizontal>
</af:panelForm>
Message was edited by:
samsam
Message was edited by:
samsam
Message was edited by:
samsam

Answer 1

Hi,
there is no API available to read from the browser cache. The way the browser cache works is that it retrieves the content itself if a image is referenced by a known URL. If the servlet streams an image then cache usage is not an option at all. If the servlet returns an image URL to a static image then it should do
Frank