New subject: Feedback - CDI bootstrap API (CDI-26)

Wednesday, 4 March 2015

Hmm.. comments in line.

On Wed, Mar 4, 2015 at 4:49 AM Antoine Sabot-Durand <
antoine(a)sabot-durand.net&gt; wrote:

...
 Hi John,

 I think it could be a good idea to write down all of these to have a more
 stable doc for discussion. You should update the google doc with the result
 of this discussion.

 I agree with the following points in this thread :

 - Minimize the number of new Class / Interface. CDI and CDIProvider usage
 is still not very clear for end user so we should add the strict minimum
 and try to enhance existing API / SPI when possible

It seems odd to me that we're rehashing decisions made during the EG
meetings.  Not putting it in CDI was discussed in several meetings at the
beginning of the year, and it seemed like the agreement was putting it in
CDI was a bad idea.

...
 - Be able to bootstrap CDI without returning BeanManager (env if the
API
 give possibility to access it if needed). End user don’t need that : CDI
 app can start with an observer for instance

Agreed, but I think we need to provide some entry point to allow those who
aren't comfortable with programming with events to leverage it.  Returning
the CDI instance makes that easier to do than returning the BeanManager.

...

 Something not dealt with but that we should keep in mind :
 - Providing a Java SE solution that could be easily used for a servlet
 bootstrap of CDI. I don’t know if we’ll standardize this but we definitely
 should keep this use case in mind

 and my bonus, it’s out of scope but I didn’t see anytime there that
 prevent this nice to have:
 - support the possibility to boot multiple BeanManager in Java SE.

 We talked about this one as well on the EG, either this year or late last
year.  I thought the decision at that time was that we wouldn't allow
multiple containers at once in SE.

...
 Antoine

 Le 1 mars 2015 à 15:13, John D. Ament <john.d.ament(a)gmail.com&gt; a écrit :

 So, I think I've gathered enough feedback at this point, and seen some of
 the API changes.  I'll hopefully be including some doc changes this week,
 but one question - do we want to start the SE specific stuff as its own
 asciidoc file?

 Changes made:

 - Changed return value to CDI<Object> to provide better capability out of
 the box.
 - Added AutoCloseable to CDIContainer, provided default implementation of
 calling shutdown.
 - Added synchronization support to the method body that retrieves the
 singleton instance (BTW, I'm not sure if this is even useful TBH as each
 impl, including the RI, needs to provide this class in its own format).
 - Made the params map typed to <String,Object>

 @Romain Your case isn't really supportable yet, until we have static
 injection support.  You'd still have to have a managed version of Runner to
 work against.

 John

 On Sat, Feb 28, 2015 at 4:11 PM Romain Manni-Bucau <rmannibucau(a)gmail.com&gt;
 wrote:

> Yes but not the way to get an instance. Even Unmanaged does it.
>
> What can be awesome is to have static inject for it:
>
> public class Runner {
>
> @Inject
> private static MyMain main;
>
> public static void main(String[] arg) {
>     try (CDIContainer c = CDIContainer.newContainer()) {
>         main.doWork();
>     }
> }
>
> }
>
> And not a single additional line :).
>  Le 28 févr. 2015 19:05, "John D. Ament" <john.d.ament(a)gmail.com&gt; a
> écrit :
>
> Maybe I'm misreading, but I don't see us adding another API to do the
>> same thing here - we're introducing new functionality.
>>
>> CDIContainer/Loader on startup/shutdown of the application
>>
>> CDI for runtime usage within the application to interact with the
>> container.
>>
>> John
>>
>> On Fri, Feb 27, 2015 at 3:40 AM Romain Manni-Bucau <
>> rmannibucau(a)gmail.com&gt; wrote:
>>
>>> sure I fully agree excepted I think introducing yet another API to do
>>> the same thing is not good so super tempting to skip it and wait for
>>> feedbacks rather than introducing it eagerly.
>>>
>>>
>>> Romain Manni-Bucau
>>> @rmannibucau
>>> http://www.tomitribe.com
>>> http://rmannibucau.wordpress.com
>>> https://github.com/rmannibucau
>>>
>>>
>>> 2015-02-27 8:05 GMT+01:00 Jozef Hartinger <jharting(a)redhat.com&gt;:
>>> > My point is that from the application perspective, the user obtains
>>> one
>>> > container handle for eventual shutdown (CDIContainer) and then looks
>>> up a
>>> > different container handle (CDI) that they can use for real work
>>> (lookup /
>>> > event dispatch / etc.) It would be cleaner if the container gave away
>>> a
>>> > single handle that can do all of that.
>>> >
>>> >
>>> > On 02/26/2015 05:42 PM, Romain Manni-Bucau wrote:
>>> >
>>> > Not sure I get how a CDI instance can help.
>>> >
>>> > But container.getBeanManager() sounds nice is not a shortcut for
>>> > CDI.current().getBm() otherwise it looks like duplication to me.
>>> >
>>> > Can we make container not contextual - dont think so? If so it makes
>>> sense
>>> > otherwise I fear it doesnt add much.
>>> >
>>> > Le 26 févr. 2015 16:19, "Jozef Hartinger"
<jharting(a)redhat.com&gt; a
>>> écrit :
>>> >>
>>> >> I like the initialize + close() combination and the
>>> try-with-resources
>>> >> usage.
>>> >> What looks weird to me is that at line one you obtain a container
>>> handle:
>>> >>
>>> >> try (CDIContainer container = CDIContainer.newCDIContai...
>>> >> CDI.current().getBeanManager() ...
>>> >>
>>> >> and then at line two you call a static method to perform a
container
>>> >> lookup :-/
>>> >>
>>> >> An API that allows you to use the container handle you already got
>>> is way
>>> >> better IMO, e.g.:
>>> >>
>>> >> try (CDIContainer container = CDIContainer.newCDIContai...
>>> >> container.getBeanManager()
>>> >>
>>> >> If CDIContainer.newCDIContainer() returns an CDI instance or its
>>> subclass,
>>> >> we get this easily.
>>> >>
>>> >> On 02/26/2015 08:58 AM, Romain Manni-Bucau wrote:
>>> >>>
>>> >>> Hi guys
>>> >>>
>>> >>> why note keeping it simple?
>>> >>>
>>> >>> try (CDIContainer container = CDIContainer.newCDIContainer(/*
>>> optional
>>> >>> map to configure vendor features */)) {
>>> >>>       CDI.current().getBeanManager()....
>>> >>> }
>>> >>>
>>> >>> Not sure the point having initialize() + having shutdown =
close
>>> >>> really makes the API more fluent and modern IMO.
>>> >>>
>>> >>> Also to be fully SE I guess provider() method would be needed
even
>>> if
>>> >>> optional (SPI usage by default):
>>> >>>
>>> >>> try (CDIContainer container =
>>> >>>
>>> >>>
CDIContainer.provider("org.jboss.weld.WeldCdiContainerProvider").
>>> newCDIContainer())
>>> >>> {
>>> >>>       CDI.current().getBeanManager()....
>>> >>> }
>>> >>>
>>> >>> Finally I think having a kind of getInstance shortcut could be
a
>>> plus for
>>> >>> SE:
>>> >>>
>>> >>> try (CDIContainer container = CDIContainer.newCDIContainer()) {
>>> >>>       container.newInstance(MyAppRunner.class /* optional
>>> qualifiers */
>>> >>> ).run(args);
>>> >>> }
>>> >>>
>>> >>> Using container to get an instance would create the instance
and
>>> bind
>>> >>> it to the container lifecycle (mainly for predestroy) avoiding
this
>>> >>> boilerplate code in all main which will surely only be used to
>>> launch
>>> >>> a soft.
>>> >>>
>>> >>> wdyt?
>>> >>>
>>> >>>
>>> >>>
>>> >>> Romain Manni-Bucau
>>> >>> @rmannibucau
>>> >>> http://www.tomitribe.com
>>> >>> http://rmannibucau.wordpress.com
>>> >>> https://github.com/rmannibucau
>>> >>>
>>> >>>
>>> >>> 2015-02-26 8:32 GMT+01:00 Jozef Hartinger
<jharting(a)redhat.com&gt;:
>>> >>>>
>>> >>>> Comments inline
>>> >>>>
>>> >>>> On 02/25/2015 05:53 PM, John D. Ament wrote:
>>> >>>>
>>> >>>> Sorry Jozef, your email fell into the pits of google
inbox's "smart
>>> >>>> sorting"
>>> >>>> features.
>>> >>>>
>>> >>>> On Thu, Feb 12, 2015 at 3:18 AM Jozef Hartinger <
>>> jharting(a)redhat.com&gt;
>>> >>>> wrote:
>>> >>>>>
>>> >>>>> Hi John, comments inline:
>>> >>>>>
>>> >>>>>
>>> >>>>> On 02/11/2015 06:02 PM, John D. Ament wrote:
>>> >>>>>
>>> >>>>> Jozef,
>>> >>>>>
>>> >>>>> Most of what you see there is taken from the original
doc, since
>>> >>>>> everyone
>>> >>>>> seemed to be in agreement.  I think the map is just a
safeguard
>>> in case
>>> >>>>> of
>>> >>>>> additional boot options available in some
implementations (e.g. I
>>> think
>>> >>>>> OWB/OpenEJB have some options.. currently OpenEJB
supports an
>>> embedded
>>> >>>>> CDI
>>> >>>>> boot mode).
>>> >>>>>
>>> >>>>> No, I am fine with the map. What I am questioning is the
type of
>>> the
>>> >>>>> map.
>>> >>>>> Usually, data structures with a similar purpose use
Strings as
>>> their
>>> >>>>> keys.
>>> >>>>> This applies to ServletContext attributes,
InvocationContext data,
>>> >>>>> Servlet
>>> >>>>> request/session attributes and others. I am therefore
wondering
>>> whether
>>> >>>>> there is a usecase for the proposed unbound key
signature or not.
>>> >>>>
>>> >>>>
>>> >>>> I think that's more of a placeholder, I was assuming it
would be
>>> >>>> Map<String,Object> once we clarify everything.
>>> >>>>
>>> >>>>>
>>> >>>>>
>>> >>>>> We spoke a few times about BeanManager vs CDI. 
BeanManager was
>>> >>>>> preferable
>>> >>>>> since there's no easy way to get the the instance,
CDI is easier
>>> to get
>>> >>>>> and
>>> >>>>> more aligned with how you would get it.  Usually people
expect the
>>> >>>>> BeanManager to be injected or available via JNDI,
neither would
>>> be the
>>> >>>>> case
>>> >>>>> here.
>>> >>>>>
>>> >>>>> If CDI 2.0 targets Java SE then this container
initialization API
>>> will
>>> >>>>> become something that ordinary application developers
use to
>>> start/stop
>>> >>>>> CDI
>>> >>>>> in their applications. It therefore cannot be considered
an SPI
>>> but
>>> >>>>> instead
>>> >>>>> should be something easy to use. On the other hand,
BeanManager is
>>> >>>>> definitely an SPI. It is used in extension, frameworks
and
>>> generally
>>> >>>>> for
>>> >>>>> integration. Not much by applications directly.
Therefore, I
>>> don't see
>>> >>>>> how
>>> >>>>> the container bootstrap API and BeanManager fit
together. IMO the
>>> >>>>> bootstrap
>>> >>>>> API should expose something that makes common tasks
(obtaining a
>>> >>>>> contextual
>>> >>>>> reference and firing and event) easy, which the CDI
class does.
>>> >>>>>
>>> >>>>> Plus do not forget that BeanManager can be obtained
easily using
>>> >>>>> CDI.getBeanManager().
>>> >>>>
>>> >>>>
>>> >>>> I'm not disagreeing.  There's a few things I'd
consider:
>>> >>>>
>>> >>>> - Is this mostly for new apps or existing?  If existing,
it's
>>> probably
>>> >>>> using
>>> >>>> some internal API, if new it can use whatever API we give.
>>> >>>> - I don't want to return void, we should give some kind
of
>>> reference
>>> >>>> into
>>> >>>> the container when we're done booting.
>>> >>>>
>>> >>>> Agreed, we should not be returning void.
>>> >>>>
>>> >>>> - CDI is a one step retrievable reference, where as
BeanManager is
>>> a two
>>> >>>> step reference.  With that said, BeanManager makes more
sense to
>>> return
>>> >>>> here.  Another thought could be we invent some new class
that has
>>> both,
>>> >>>> but
>>> >>>> that's really redundant.
>>> >>>>
>>> >>>> Why do you think BeanManager makes more sense here?
Especially
>>> given the
>>> >>>> assumption that application code is going to call this
>>> init/shutdown
>>> >>>> API, I
>>> >>>> don't see BeanManager as making more sense.
>>> >>>>
>>> >>>>
>>> >>>>>
>>> >>>>>
>>> >>>>> Yes, this is the container start API.  Sounds like you
have some
>>> good
>>> >>>>> ideas for things like XML configuration or programmatic
>>> configuration,
>>> >>>>> both
>>> >>>>> of which are being tracked under separate tickets.  One
idea
>>> might be
>>> >>>>> for an
>>> >>>>> optional param in the map to control packages to
scan/ignore, in
>>> that
>>> >>>>> map.
>>> >>>>>
>>> >>>>> I am wondering whether this configuration should be
something
>>> optional
>>> >>>>> built on top of the bootstrap API or whether we should
consider
>>> making
>>> >>>>> it
>>> >>>>> mandatory. Either way, we cannot add the bootstrap API
to the spec
>>> >>>>> without
>>> >>>>> explicitly defining how it behaves. My implicit
assumption of the
>>> >>>>> proposal
>>> >>>>> is that the container is supposed to scan the entire
classpath for
>>> >>>>> explicit
>>> >>>>> or implicit bean archives (including e.g. rt.jar),
discover
>>> beans, fire
>>> >>>>> extensions, etc. This worries me as this default
behavior is far
>>> from
>>> >>>>> being
>>> >>>>> lightweight, which CDI for Java SE initially aimed to
be.
>>> >>>>
>>> >>>>
>>> >>>> Yes, the spec must be updated to reflect the behavior of SE
mode.
>>> I
>>> >>>> plan to
>>> >>>> get that completely into the google doc before opening any
spec
>>> changes
>>> >>>> in a
>>> >>>> PR.
>>> >>>>
>>> >>>>>
>>> >>>>>
>>> >>>>> We didn't want to over load the CDI interface.  It
already does a
>>> lot.
>>> >>>>> This is really SPI code, CDI even though it's in the
spi package
>>> is
>>> >>>>> used in
>>> >>>>> a lot of application code.
>>> >>>>>
>>> >>>>> I would personally prefer to have it all in one place.
Having
>>> >>>>> CDIContainer, CDIContainerLoader, CDI and CDIProvider
makes it
>>> more
>>> >>>>> difficult to know when to use what.
>>> >>>>
>>> >>>>
>>> >>>> The problem is that most CDI (the interface) operations are
>>> against a
>>> >>>> running container.  I think we spoke about leveraging
CDIProvider
>>> at one
>>> >>>> point (in fact, I mistakenly called CDIContainer CDIProvider
not
>>> even
>>> >>>> realizing it was there).  I doubt that most app developers
use it
>>> >>>> currently,
>>> >>>> there's not even a way to get a reference to it that
I'm aware
>>> of.  It's
>>> >>>> used by the implementor only.
>>> >>>>
>>> >>>> I don't think there's a conflict. CDI class would
still only
>>> provide
>>> >>>> methods
>>> >>>> to be run against a running container. The difference is
that there
>>> >>>> would be
>>> >>>> additional static methods to get this running container
(CDI
>>> class) to
>>> >>>> you
>>> >>>> by starting the container.
>>> >>>>
>>> >>>> Either way, I agree that reusing CDIProvider is a must.
There is no
>>> >>>> reason
>>> >>>> to define a new class for the same purpose.
>>> >>>>
>>> >>>>
>>> >>>> I expect that my changes in the CDI spec around this will
state,
>>> along
>>> >>>> the
>>> >>>> lines of:
>>> >>>>
>>> >>>> To retrieve a CDIContainer to launch, do this:
>>> >>>>
>>> >>>> CDIContainer container =
CDIContainerLocator.getCDIContainer();
>>> >>>> container.initialize();
>>> >>>> ... do work
>>> >>>>
>>> >>>> Once you want to shutdown the container, do this:
>>> >>>>
>>> >>>> container.shutdown();
>>> >>>>
>>> >>>> (we may want to consider implementing AutoCloseable, an
oversight
>>> on my
>>> >>>> part)
>>> >>>>
>>> >>>> and then later on
>>> >>>>
>>> >>>> - What happens if I call CDIContainerLocator in an app
server
>>> >>>>
>>> >>>> - It throws an IllegalStateException.
>>> >>>>
>>> >>>> - The container provides no beans of type CDIContainer, it
is
>>> managed
>>> >>>> outside of the CDI container.
>>> >>>>
>>> >>>>
>>> >>>>>
>>> >>>>>
>>> >>>>> John
>>> >>>>>
>>> >>>>> On Wed Feb 11 2015 at 4:21:50 AM Jozef Hartinger <
>>> jharting(a)redhat.com&gt;
>>> >>>>> wrote:
>>> >>>>>>
>>> >>>>>> Hi John, some thoughts:
>>> >>>>>>
>>> >>>>>> - instead of using BeanManager it makes more sense
to me to
>>> return a
>>> >>>>>> CDI
>>> >>>>>> instance, which is a more user-friendly API (and it
also exposes
>>> >>>>>> access to
>>> >>>>>> BeanManager)
>>> >>>>>> - is there a usecase for arbitrary keys of the
"params" map or is
>>> >>>>>> Map<String, ?> sufficient?
>>> >>>>>> - if we could move the shutdown() method from
CDIContainer to the
>>> >>>>>> actual
>>> >>>>>> container handle that we obtain from initialize(),
that would
>>> look
>>> >>>>>> more
>>> >>>>>> object-oriented
>>> >>>>>> - what exactly is initialize() supposed to do? Is it
supposed to
>>> start
>>> >>>>>> scanning the entire classpath for CDI beans? That
could be a
>>> problem
>>> >>>>>> especially with spring-boot-like fat jars. I think
we need an
>>> API to
>>> >>>>>> tell
>>> >>>>>> the container which classes / packages to consider.
Something
>>> like
>>> >>>>>> Guice's
>>> >>>>>> binding API perhaps?
>>> >>>>>>
>>> >>>>>> - the proposal makes me wonder whether retrofitting
this
>>> functionality
>>> >>>>>> to
>>> >>>>>> the CDI class wouldn't be a better option. It
could look like:
>>> >>>>>>
>>> >>>>>> CDI container = CDI.initialize();
>>> >>>>>> container.select(Foo.class).get();
>>> >>>>>> container.shutdown();
>>> >>>>>>
>>> >>>>>> compare it to:
>>> >>>>>>
>>> >>>>>> CDIContainer container = CDIContainerLoader.
getCDIContainer();
>>> >>>>>> BeanManager manager = container.initialize();
>>> >>>>>> manager.getBeans(...);
>>> >>>>>> container.shutdown(manager);
>>> >>>>>>
>>> >>>>>>
>>> >>>>>> On 02/10/2015 06:58 PM, John D. Ament wrote:
>>> >>>>>>
>>> >>>>>> All,
>>> >>>>>>
>>> >>>>>> I have the updated API here, and wanted to solicit
any final
>>> feedback
>>> >>>>>> before updating the google doc and spec pages.
>>> >>>>>>
>>> >>>>>>
>>> >>>>>>
>>> >>>>>>
https://github.com/johnament/cdi/commit/2c362161e18dd521f8e8
>>> 3c27151ddad467a1c01c
>>> >>>>>>
>>> >>>>>> Let me know your thoughts.
>>> >>>>>>
>>> >>>>>> Thanks,
>>> >>>>>>
>>> >>>>>> John
>>> >>>>>>
>>> >>>>>>
>>> >>>>>> _______________________________________________
>>> >>>>>> cdi-dev mailing list
>>> >>>>>> cdi-dev(a)lists.jboss.org
>>> >>>>>> https://lists.jboss.org/mailman/listinfo/cdi-dev
>>> >>>>>>
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>>> licenses
>>> >>>>>> the
>>> >>>>>> code under the Apache License, Version 2
>>> >>>>>> (http://www.apache.org/licenses/LICENSE-2.0.html).
For all
>>> other ideas
>>> >>>>>> provided on this list, the provider waives all
patent and other
>>> >>>>>> intellectual
>>> >>>>>> property rights inherent in such information.
>>> >>>>>>
>>> >>>>>>
>>> >>>>
>>> >>>> _______________________________________________
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>>> >>>> intellectual
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>>> >>
>>> >>
>>> >
>>>
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Re: [cdi-dev] Feedback - CDI bootstrap API (CDI-26)