Re: [Trinidad] how to avoid loading tr:table rows twice

[Renzo Tomaselli]

Thanks, Vadim. It works fine. As concerning specifically tr:table, a derived question arises: assume that such table is readonly, but it has selection capabilities. If the associated bean returns an empty collection model (isRowAvailable always false), would then a valid RowKeySet still available ? After all such keys are provided by the client, but I don't know whether the table decoding process pretends to find them in the model. If this is the case, we might still provide empty fields, thus avoiding to go through the business layer. Correct ? -- Renzo Vadim Dmitriev wrote: 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 ?