Hi, Renzo.
I don't think any component would do such a thing internally. After all,
component just evaluate EL and can't figure out, when it is undesired.
As a solution I can recommend you to use
"FacesContext.getCurrentInstance().getRenderResponse()" to detect, when
getter is called during renderResponse phase:
public Object getSomeVal()
{
if( _someField != null &&
FacesContext.getCurrentInstance().getRenderResponse() )
{
_someField = getDataFromSlowExternalSource();
}
return _someField;
}
In the following code snippet, request to some external data source will
be issued only once in the renderResponse phase.
Renzo Tomaselli wrote:
> Hi all, in all cases where a readonly tr:table is involved - and
> needed data are to be loaded from the business layer - then this
> occurs twice.
> Once during restore view (decode) and again during rendering (encode).
> The first time is fairly useless for a readonly component, but the
> overall doubling can be expensive while loading from a complex
> business layer (e.i. a db).
> AFAIK this is a JSF side-effect which should affect all components,
> not a Trinidad issue. Trees are affected by the same problem as they
> are typically readonly.
> I just wonder if anybody else got the same conclusion and there is any
> workaround.
> The only one I can think about concerns detecting current phase and
> skipping loading while restoring a view (e .g. returning null as a
> value attribute, or at least an empty collection).
> Any better suggestion ?
>
