13 Mar
2015
13 Mar
'15
1:30 a.m.
Hi Sergiu,
On 12 Mar 2015 at 20:45:41, Sergiu Dumitriu (sergiu@xwiki.org(mailto:sergiu@xwiki.org))
wrote:
On 03/12/2015 07:24 AM, Eduard Moraru wrote:
I’ll let Edy answer this but it doesn’t change the possibility to use typed annotations
for Priorities.
Hi,
On Thu, Mar 12, 2015 at 12:03 PM, vincent(a)massol.net
wrote:
For your love, here's another opinion.
1. I spent a while looking for javax.annotations.Priority, since I
didn't see it at
http://docs.oracle.com/javase/7/docs/api/javax/annotation/package-summary.h…
... Turns out it's a JEE class that's not in JSE. AFAIK, we're not
really using JEE yet, just JSE with a few JEE modules. Am I wrong? If
not, do we want to require JEE from now on, or is that annotation
available in a Maven Central library that doesn't bring in the whole JEE? Hi Edy,
On 12 Mar 2015 at 10:49:29, Eduard Moraru (enygma2002(a)gmail.com(mailto:
enygma2002(a)gmail.com)) wrote:
...and because they clearly express it, in their documentations, that they
accept some annotations and they define how those annotations will be
interpreted. Basically, the purpose of the javax.annotations package.
Hi,
As it's documentation [1] mentions, the usage of the @Priority annotation
should be defined by the classes it is used on:
"The effect of using the Priority annotation in any particular instance
is
defined by other specifications that define the
use of a specific class.
For example, the Interceptors specification defines the use of priorities
on interceptors to control the order in which interceptors are called."
Therefore, I suggest we use the @Priority annotation on components that
need it and that like to specify the order in which they are *used* (i.e.
perform their main task).
so what you’re suggesting is that:
@Component
@Name(“content”)
@Priority(1000)
public class ContentMacro implement Macro
has a different meaning than:
@Component
@Named(“XWiki.WatchListJobClass")
@Priority(1000)
public class WatchListJobClassDocumentInitializer ...
because one if a Macro and the other one is a Document Initializer
right?
(BTW note that this wouldn’t work if in the
future we start supporting
several roles per component impl.)
So it means that people reading the code need to understand that even
though it’s the same annotation, it’ll have a different meaning.
Compare this to:
@Component
@Name(“content”)
@MacroPriority(1000)
I don`t find this better since it does not tell me what the macro does with
that priority. @MacroExcutionPriority would have been clear, if that is
what we pursue.
public class ContentMacro implement Macro
and
@Component
@Named(“XWiki.WatchListJobClass")
@DocumentInitializerPriority(1000)
public class WatchListJobClassDocumentInitializer ...
IMO the second one is more clear in its intent. WDYT?
Honestly, I am not a big fan of annotations, specially in Java, and I try
to keep them to a minimal as much as possible. It feels like a shortcut
that leads to a dead end. They are not code, but configuration and, as
such, modifying configuration should not require recompiling the code.
Back to our particular discussion, AFAIK, we are not doing multiple roles
per implementation. That, indeed, would probably not work with the javax
Priority annotation due to lack of specificity.
I do see the advantages of typed annotations, but also the need to be aware
of more and more annotations, as they come, when our usecase is pretty
simple and would be well satisfied by the javax Priority one. That is the
main reason why I looked for a more generic solution instead of just making
a new annotation for the document initializer use case. I find it uselessly
polluting.
I`d love to hear more opinions on this :) 2. I agree with you that this is configuration, not
code, thus changing
it shouldn't require recompiling code. I'm -0.5 for the original
proposal because of this.
If you check all existing Macros for example, we already use harcoded priorities
everywhere (1000 by default) and some Macros have higher and lower values, and these
values are static and require re-compilation if you change them. That’s ok because the
priorities are not supposed to change (neither are the hints for components for the
Threading model - singleton, per thread). Actually they should not change because the
macros are coded to work with the defined priority.
I really don’t see the difference between hardcoding in java vs hardcoding in an
annotation.
However (an again since nobody commented on that :)), I really don’t think that adding
get/setPriority methods to business interfaces is a good thing. So typed annotations still
win for me.
3. I'd like to resurect
http://markmail.org/thread/mrbmbn45cltfvh57 and
enhance/build on top of it. Since we're already using an external file
for listing components, and since we already have a kind of priority in
that file, why not use that file to also give components priorities. If
someone wants to change the priority of a component, all that's required
is to add a new file in WEB-INF/classes with the new priority of the
component.
Before we discuss a syntax, anybody wants to veto this?
I need some time to read again this thread. I’ll try to do this tomorrow.
Thanks
-Vincent
Thanks,
Eduard
>
>> Priorities on other behaviors that are added to a component (for example
>> through interfaces like Initializable or Disposable, interfaces which are
>> not components themselves) should provide their own specialized
>> (behavior-driven) priority annotations (e.g. @DisposePriority,
>> @InitializationPriority, etc.).
>>
>> Note: If we want to explore the possibility of using our own generic
>> Priority annotation, we need to consider the fact that multiple
> annotations
>> on the same java class is only supported [1] starting with java 1.8.
> Until
>> then, the commonly used workaround [3] seems cumbersome to use.
>
> Yep, I’d really not like to use a generic annotation with the namespace
> being specified. I much much prefer typed annotations.
>
> Thanks
> -Vincent
>
>> Thanks,
>> Eduard
>>
>> ----------
>> [1] http://docs.oracle.com/javaee/7/api/javax/annotation/Priority.html
>> [2] http://bugs.java.com/bugdatabase/view_bug.do?bug_id=7151010
>> [3]
>>
>
http://stackoverflow.com/questions/1554112/multiple-annotations-of-the-same…
>>
>> On Thu, Mar 12, 2015 at 10:41 AM, vincent(a)massol.net
>> wrote:
>>
>>> Hi devs,
>>>
>>> As part of http://jira.xwiki.org/browse/XWIKI-11905, Edy has started
>>> using the Java @Priority annotation.
>>>
>>> This seems very good and I personally didn’t know about this annotation
>>> before (maybe it’s been introduced not that long ago?). So for me it
> raises
>>> the question of: do we want to use this annotation more and how does it
>>> compare with what we’ve done so far.
>>>
>>> I can think of a few places that could have used it:
>>>
>>> * Macros.get/setPriority(). It should be possible to add support for
>>> @Priority and modify MacroTransformation to use that annotation.
>>> * Transformations. We have a jira issue opened for adding support for
>>> Priority in Transformation’s executions (in TransformationManager).
>>> * @DisposePriority (used by ECM).
>>> * TranslationBundle.get/setPriority()
>>> * … and probably some other places…
>>>
>>> However, I think there’s a namespacing problem. For example imagine
> that
>>> we code a Macro and set @Priority on that Macro component. The ECM
> could
>>> interpret it as a dispose priority while the MacroTransformation could
>>> interpret it as an execution priority…
>>>
>>> Globally I think that use an annotation for expressing priority is
> great
>>> and much better than what we’ve done in the past with get/setPriority()
>>> methods. It’s better because priority is not a business concept and
> we’re
>>> polluting the business interface with it.
>>>
>>> Now, in order to fix the namespacing issue, I think that the best
> solution
>>> is that each module requiring some priority should introduce its own
>>> annotation and should NOT depend on the @Priority one from the JDK
> (i.e. we
>>> ban the usage of it).
>>>
>>> WDYT?
>>>
>>> Thanks
>>> -Vincent
>>>
>>>
>>> W
--
Sergiu Dumitriu