Hi
Yes, the strategy done in MyFaces is far more simple, but since this is
considered an implementation detail, how it works falls out of the scope of
the discussion of the list.
The thing you need to consider in this problem is EL evaluation is not as
slow as you can imagine, compared with multiple hashmap.get() calls. On the
other side isRendered() method can be called multiple times and most of
them do not do any EL evaluation. If you have a component tree with
multiple component and some of them has an EL on isRendered(), you will not
gain anything if you add extra hashmap.get() calls on every isRendered()
call, just to try to gain something on the components that use it (which
can be just a couple of them).
regards,
Leonardo Uribe
2015-01-12 15:55 GMT-05:00 manfred riem <manfred.riem_at_oracle.com>:
> Since you are telling me there are other tested strategies that are far
> more simple can you elaborate?
>
> Manfred
>
>
> On 1/12/15, 2:53 PM, Leonardo Uribe wrote:
>
> Hi Manfred
>
> Well, you can make it work, but all that logic seems overkill to me. It
> could work, but I doubt about its convenience against other tested
> strategies for the same problem that are far more simple.
>
> regards,
>
> Leonardo Uribe
>
> 2015-01-12 15:07 GMT-05:00 manfred riem <manfred.riem_at_oracle.com>:
>
>> Hi Leonardo,
>>
>> I disagree, as when the rendering starts in each encodeBegin it can get
>> the elCacheable transientHelper attribute from the parent and then set is
>> own elCacheable transientHelper attribute. And if you cannot find the
>> elCacheable transientHelper attribute on the parent you err on the side of
>> assuming it is not EL cacheable. And voila no going up many levels.
>>
>> Manfred
>>
>>
>> On 1/12/15, 12:26 PM, Leonardo Uribe wrote:
>>
>> Hi
>>
>> It could be one, it could be many. The problem is the component doesn't
>> know how many levels up should be checked to decide if there is an
>> iteration, so it will be forced to go all levels to the top, over and over.
>> There is no contextual information about the current iteration. I think it
>> is quite easy to find examples where it will fail.
>>
>> regards,
>>
>> Leonardo Uribe
>>
>> 2015-01-12 13:08 GMT-05:00 manfred riem <manfred.riem_at_oracle.com>:
>>
>>> How so? It is just calling one component up?
>>>
>>> Manfred
>>>
>>>
>>> On 1/12/15, 12:06 PM, Leonardo Uribe wrote:
>>>
>>> Hi Manfred
>>>
>>> MR>> The encodeBegin method has access to the parent component
>>>
>>> The problem is do that will increase the algorithm complexity. We need
>>> to
>>> keep it on lineal complexity (O(n)), otherwise the optimization will not
>>> be effective.
>>>
>>> regards,
>>>
>>> Leonardo Uribe
>>>
>>> 2015-01-12 12:44 GMT-05:00 manfred riem <manfred.riem_at_oracle.com>:
>>>
>>>> Hi Leonardo,
>>>>
>>>> The encodeBegin method has access to the parent component, so it can
>>>> determine the parent ElCacheable from it. If the parent is not an
>>>> ELCacheable instance the component itself cannot be either, otherwise it
>>>> can look its getter.
>>>>
>>>> Regards,
>>>> Manfred
>>>>
>>>>
>>>> On 1/12/15, 11:40 AM, Leonardo Uribe wrote:
>>>>
>>>> Hi
>>>>
>>>> I don't think an interface could work, because it is the parent, not
>>>> the child who defines the iteration strategy. It is a fact that we reuse
>>>> the same component instances for different rows (UIData).
>>>>
>>>> regards,
>>>>
>>>> Leonardo Uribe
>>>>
>>>> 2015-01-12 9:13 GMT-05:00 manfred riem <manfred.riem_at_oracle.com>:
>>>>
>>>>> Hi Hanspeter,
>>>>>
>>>>> I am trying to formalize it for the RenderPhase only, which would mean
>>>>> stating something like the following:
>>>>>
>>>>> 1. ElCacheable would be defined by an interface
>>>>> 2. ElCacheable would operate only in RENDER_RESPONSE
>>>>> a. Which means a component would not be allowed to change the
>>>>> value of an EL expression
>>>>> b. For an iterating component it would not cache and thus not
>>>>> implement ElCacheable
>>>>> c. For components not implementing the ElCacheable interface it
>>>>> would operate as if it was not cacheable.
>>>>> 3. Add a getter / setter that stores elCacheable on the UIComponent
>>>>>
>>>>> Am I missing something here?
>>>>>
>>>>> Thoughts?
>>>>> Manfred
>>>>>
>>>>>
>>>>>
>>>>> On 1/9/15, 5:18 PM, Hanspeter wrote:
>>>>>
>>>>> Hi Experts.
>>>>>
>>>>> I think this is worth pushing +1.
>>>>>
>>>>> The multiple rendered attribute evaluation bothers most in the
>>>>> render phase because isRendered() is called by every
>>>>> UIComponent(Base).encode* method. So maybe a first step would be to improve
>>>>> the encode* methods such that for an encodeAll() cycle the rendered
>>>>> attribute is cached. That is possible with a few lines of code - I happily
>>>>> provide the changes.
>>>>>
>>>>> E.g. encodeAll() and/or encodeBegin() could enable renderedCaching,
>>>>> isRendered() stores the rendered result on a component private Boolean, and
>>>>> in encodeEnd() rendered caching is disabled and reset. That way without
>>>>> additional effort rendered is reset for the next iteration. But still this
>>>>> would reduce evaluate times by factor 3 to 4 per component encoding.
>>>>>
>>>>> I'm not sure whether rendered caching on a broader scope makes
>>>>> sense, e.g. for phases 2-5. In csJSF component library we did some rendered
>>>>> caching, but had to reset the cache once per phase and within iterating
>>>>> components as well. And I think rendered is rarely evaluated more often as
>>>>> it was reset in these execution phases.
>>>>>
>>>>> Best regards
>>>>> Hanspeter
>>>>>
>>>>>
>>>>>
>>>>> 2015-01-09 19:12 GMT+01:00 Bauke Scholtz <balusc_at_gmail.com>:
>>>>>
>>>>>> +1
>>>>>>
>>>>>> Ideally, the UIComponent#isRendered() should cache the value on a
>>>>>> per-phase and per-iteration basis. It would be awesome too if iteration
>>>>>> components implement a common interface or abstract class, which should
>>>>>> also simplify a lot of other things related to a.o. setting the currently
>>>>>> iterated item and state saving.
>>>>>>
>>>>>> Cheers, B
>>>>>>
>>>>>>
>>>>>> On Fri, Jan 9, 2015 at 7:00 PM, manfred riem <manfred.riem_at_oracle.com
>>>>>> > wrote:
>>>>>>
>>>>>>> Whoops, sending to right list. Please ignore it on the other.
>>>>>>>
>>>>>>> -------- Original Message -------- Subject: [jsr344-experts]
>>>>>>> [941-ReduceELCalls] DISCUSSION Date: Fri, 09 Jan 2015 11:51:14
>>>>>>> -0600 From: manfred riem <manfred.riem_at_oracle.com>
>>>>>>> <manfred.riem_at_oracle.com> Reply-To:
>>>>>>> jsr344-experts_at_javaserverfaces-spec-public.java.net Organization: Oracle
>>>>>>> Corporation To: jsr344-experts_at_javaserverfaces-spec-public.java.net CC:
>>>>>>> Max Starets <max.starets_at_oracle.com> <max.starets_at_oracle.com>, Andy
>>>>>>> Schwartz <andy.schwartz_at_oracle.com> <andy.schwartz_at_oracle.com>
>>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> As we all know the number of times an EL expression is evaluated
>>>>>>> during render is higher than it could be.
>>>>>>>
>>>>>>> To see if there is a potential to reduce that number I want to ask
>>>>>>> the most important question first as it determines whether or not this
>>>>>>> issue is even worth pursuing?
>>>>>>>
>>>>>>> *Is it safe to assume that during rendering and not as a child of an
>>>>>>> iterating component the value of the EL expression will stay stable?*
>>>>>>>
>>>>>>> Regards,
>>>>>>> Manfred
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>