How to optimize the content delivery to an af:table ?

Question

http://download.oracle.com/docs/cd/E15523_01/apirefs.1111/e12419/tagdoc/af_table.html
I use a table like this :
<af:table var="row" id="t1" value="#{listUsers.users}" ... >
The table calls automatically the getUsers() method between 5 and 10 times each time I refresh the page.jspx
I don't understand why the table does NOT call the table only ONCE.
It seems problematic to me since the getUsers() method takes the data from the database so it will impact the performance.
Another problem : this table uses <f:facet name="detailStamp">
and when I click on the + to expand a row, again it calls getUsers(), but the data should be already available
Those problems do NOT seem to be related to :
- the number of column
- the number of row (I used 2 rows for my tests)
- the browser
- the "contentDelivery" attribute of af:table
As a fix, I could verify in my getUsers() method that the data is already available but it seems to me that the ADF table should not call getUsers() so many times,
Thanks in advance,
JP

Answer 1

Yes I have seen this behavior many times before.
It appears that getters are called for tag attribute EL often as many times as there are requests for files in your jsp page.
My experience is with respect to ADF 10g, not 11g.
So for example, if you bring in a .js file, a .css file, and use a jsp:include or two, now you have 4 or 5 runs of your getters.
So I have solved some of this by doing some caching in a session-scoped variable of some sort of whatever value you need to save...or even at the request level. Because of this issue you do need to be aware of placing expensive operations in your managed beans and other things that EL can tie an attribute to.