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Posted to dev@struts.apache.org by Karan Malhi <ka...@gmail.com> on 2009/02/22 04:44:28 UTC
[QUESTION]
Hi,
I work on the OpenEJB project. I wanted to add support for injecting
resources into struts actions i.e. if somebody creates a struts based web
app and deploys it in Tomcat + OpenEJB, then I want the user to be able to
annotate the struts actions with @EJB, @Resource etc and then have OpenEJB
inject those resources. To do that, I need to find out which classes in the
web-app represent actions. Initially I thought that struts.xml would contain
all the Action classes (listed as part of action elements). Then I found
out that one could also include other xml files within struts xml using the
<include/> element. Since I do not know struts 2 that well, I have a few
questions which will help me a long way to add injection support:-
1. Does the struts config files has to be named struts.xml or can it be
named something else? If yes, how would struts discover such a file?
2. Are all actions mapped in struts.xml and the included xml files (using
the include element) or there could be actions which do not need to be
listed in these xml files.
3. I was planning to write a plugin, but wanted to have access to the
ServletContext within the plugin. Could you show me how to do that -- I
tried implementing ServletContextAware in the plugin class, but that did not
work for me (maybe that interface is only supposed to be implemented by
actions)
Thanks
--
Karan Singh Malhi
Re: [QUESTION]
Posted by Piero Sartini <li...@pierosartini.de>.
> So a user would need these plugins to map actions without XML. Struts
> default behavior would require a user to map the action in the XML file and
> that would be struts.xml, right? So would it be fair to say that if I parse
> the struts.xml file and all included xml files, then I will have a list of
> all available actions in the webapp (assuming user is not using the plugins
> you mentioned) ?
Please note that these plugins are part of the default struts2 distribution.
(Convention, REST, ...) You should not rely on parsing the struts.xml. In
fact, such plugins have been around since the very first versions of s2
(called codebehind and zeroconfig). Can't remember for how long I am not
writing xml mappings for my actions...
Piero
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Re: [QUESTION]
Posted by Musachy Barroso <mu...@gmail.com>.
The config browser plugin shows all the actions mapped by struts, you
might want to look at the code for tips.
musachy
On Thu, Feb 26, 2009 at 12:27 PM, Karan Malhi <ka...@gmail.com> wrote:
> Thanks Rene. I am trying to avoid a situation where I would have to scan the
> whole classpath on web app startup. Does struts cache the information about
> all action classes somewhere? I am thinking maybe I could simply use that
> information , instead of trying to figure out the action classes on my own?
>
> On Tue, Feb 24, 2009 at 4:46 PM, Rene Gielen <gi...@it-neering.net> wrote:
>
>> If your intent is to go for a ObjectFactory implementation / extension, I
>> think it would not be necessary to distinct between action or non-action
>> classes - just check the bean to build for the EJB annotations, regardless
>> what kind of bean that is. Actually, in Struts2 not only action classes are
>> candidates for an injection like this - interceptors would also be good
>> candidates, maybe even results.
>>
>> I would really like to see "first class" EJB3 support in S2, and would also
>> be glad to help where I can
>>
>> - Rene
>>
>> Karan Malhi schrieb:
>>
>> If a class has a suffix of Action or implements the Action interface, would
>>> that automatically be treated as an action class? Would such a class
>>> require that it be listed in the struts.xml file?
>>>
>>>
>>> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <ka...@gmail.com>
>>> wrote:
>>>
>>> Thanks Wes,
>>>>
>>>> Appreciate such a prompt response.
>>>>
>>>> There are likely to be actions mapped via other means. There are many
>>>>> plugins
>>>>> available, most prominently the REST plugin and the Convention plugin
>>>>> that
>>>>> allow our users to map actions without any XML
>>>>>
>>>>
>>>> So a user would need these plugins to map actions without XML. Struts
>>>> default behavior would require a user to map the action in the XML file
>>>> and
>>>> that would be struts.xml, right? So would it be fair to say that if I
>>>> parse
>>>> the struts.xml file and all included xml files, then I will have a list
>>>> of
>>>> all available actions in the webapp (assuming user is not using the
>>>> plugins
>>>> you mentioned) ?
>>>>
>>>>
>>>>> 3. I was planning to write a plugin, but wanted to have access to the
>>>>>> ServletContext within the plugin. Could you show me how to do that -- I
>>>>>> tried implementing ServletContextAware in the plugin class, but that
>>>>>> did
>>>>>> not work for me (maybe that interface is only supposed to be
>>>>>> implemented
>>>>>>
>>>>> by
>>>>>
>>>>>> actions)
>>>>>>
>>>>> That interface is meant for actions. The best way to get a
>>>>> ServletContext
>>>>> is
>>>>> to do the following from an interceptor -
>>>>>
>>>>> final ActionContext context = invocation.getInvocationContext();
>>>>> ServletContext servletContext = (ServletContext)
>>>>>
>>>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>>>
>>>>> Although I did not manage to get access to the actual ServletContext, I
>>>> believe ActionContext.getContext().getApplication() would give me access
>>>> to
>>>> the Map of context attributes. Since I just need to read an attribute
>>>> from
>>>> it, I believe this approach should suffice.
>>>>
>>>> You may face a few issues though. I've thought briefly about EJB +
>>>>> Struts2
>>>>> lately and I'll admit to a lack of experience with EJB, but it seems to
>>>>> me
>>>>> that it would be somewhat difficult to combine the two easily. Many of
>>>>> the
>>>>> EJB
>>>>> annotations can appear on private members (i.e. @PersistenceContext). In
>>>>> Struts2, we create actions via our own ObjectFactory, which can be
>>>>> overridden
>>>>> by a plugin.
>>>>>
>>>>> On application startup we collect information about all classes which
>>>> need
>>>> injection. Then when instances of classes are created, we use that
>>>> information to perform injection. The plugin which I wanted to write
>>>> would
>>>> be an ObjectFactory and I intended to override the buildBean method and
>>>> perform the injection there. Actually, I just realized that I could get
>>>> access to the Map of ServletContext attributes as shown below:
>>>> public class OpenEJBObjectFactory extends ObjectFactory{
>>>> public Object buildBean(Class clazz, Map map) throws Exception {
>>>> Map application = (Map)map.get("application");
>>>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>>>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>>>> }
>>>> }
>>>>
>>>>
>>>> I'm not particularly familiar with OpenEJB, but I'd like to help however
>>>>> I
>>>>> can. So, let me know if you need the help.
>>>>>
>>>>> Excellent. I really appreciate it. You are already helping in a great
>>>> way
>>>> by answering my questions. Thank you so much.
>>>>
>>>> -Wes
>>>>> --
>>>>>
>>>>> Wes Wannemacher
>>>>> Author - Struts 2 In Practice
>>>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
>>>>> http://www.manning.com/wannemacher
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>
>>>>>
>>>>>
>>>> --
>>>> Karan Singh Malhi
>>>>
>>>>
>>>
>>>
>>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>> For additional commands, e-mail: dev-help@struts.apache.org
>>
>>
>
>
> --
> Karan Singh Malhi
>
--
"Hey you! Would you help me to carry the stone?" Pink Floyd
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Re: EJB annotation support - was: [QUESTION]
Posted by Rene Gielen <gi...@it-neering.net>.
See inline comments
David Blevins schrieb:
>
> On Feb 27, 2009, at 12:11 AM, Rene Gielen wrote:
>
>> While ususally DI containers build up a complete configuration of
>> known beans at application startup, the pluggable DI container support
>> for Struts2 works different. It is based on the assumption that each
>> Action, Interceptor and Validator will only need to get it's
>> dependencies injected, but will never be subject to being injected to
>> other beans - which makes perfect sense, since they are endpoints by
>> design.
>>
>> If you look at how the ObjectFactory mechanism is implemented, you
>> will see that everything happens at runtime - the bean is created, and
>> then handled over to the DI container to have it scanned for injection
>> candidates (usually determined by a name or type strategy) and wired
>> up based on the configuration the container built at application
>> startup. The SpringObjectFactory in XWork gives a good overview on how
>> this is solved.
>>
>> AFAICS this mechanism is also applicable to EJB- and
>> Common-Annotations - when ObjectFactory is requested to build a
>> certain bean, scan it for it's annotation configuration, optionally
>> remember these results in a cache, and have either the EJB container
>> component do the wiring if it provides a suitable extension point, or
>> use a kind of active proxy to interpret he annotations, ask the
>> container for the needed resources, and wire the bean up finally.
>
> That doesn't work so well for us in the current design. The code we
> have now more or less relies on knowing all the ejb, datasource, jms,
> env entry, persistence unit, persistence context, web service, and j2ee
> connector references up front so we can resolve them all, build the
> required infrastructure and objects for the app (entity managers,
> datasources, topics/queues, connection factories, orbs, mail sessions,
> web service handler chains and endpoints, connector resources), bind it
> all to jndi, and finally boot the app or report any errors or misuse of
> annotations.
>
> For at least the first iteration, it's going to be way easier to treat
> the struts objects the same as servlets or ejbs and scan them at app
> startup time.
>
I see your point. As others already said, the only correct way to get
the full set of classes to be managed by S2 is to pull them from the
configuration that is built at S2 application start, or more precisely
at the time the StrutsPrepare filter is doing it's init phase. How would
that fit into the OpenEJB lifecycle?
Nevertheless, an ObjectFactory implementation would be responsible for
doing the actual injection based on the collected configuration then.
> There are plenty of people who want more dynamic annotation processing
> (mostly to expand injection to test cases, plain clients, and misc java
> objects not managed by the container). If we had that code, it would
> definitely be useful in this situation. Might be something we can do
> down the road.
>
That would be a great feature IMO.
>
> -David
>
>>
>> David Blevins schrieb:
>>> On Feb 26, 2009, at 9:27 AM, Karan Malhi wrote:
>>>> Thanks Rene. I am trying to avoid a situation where I would have to
>>>> scan the
>>>> whole classpath on web app startup. Does struts cache the
>>>> information about
>>>> all action classes somewhere?
>>> We actually do scan the entire webapp classpath for ejbs now. So it
>>> shouldn't be that bad.
>>> Though definitely if we can get that information from struts
>>> directly, even better. I wonder if there's a chicken and egg issue
>>> with that approach though. When exactly does struts do the
>>> searching? Right now we do all our scanning before the webapp starts
>>> up.
>>> -David
>>>> On Tue, Feb 24, 2009 at 4:46 PM, Rene Gielen <gi...@it-neering.net>
>>>> wrote:
>>>>
>>>>> If your intent is to go for a ObjectFactory implementation /
>>>>> extension, I
>>>>> think it would not be necessary to distinct between action or
>>>>> non-action
>>>>> classes - just check the bean to build for the EJB annotations,
>>>>> regardless
>>>>> what kind of bean that is. Actually, in Struts2 not only action
>>>>> classes are
>>>>> candidates for an injection like this - interceptors would also be
>>>>> good
>>>>> candidates, maybe even results.
>>>>>
>>>>> I would really like to see "first class" EJB3 support in S2, and
>>>>> would also
>>>>> be glad to help where I can
>>>>>
>>>>> - Rene
>>>>>
>>>>> Karan Malhi schrieb:
>>>>>
>>>>> If a class has a suffix of Action or implements the Action
>>>>> interface, would
>>>>>> that automatically be treated as an action class? Would such a class
>>>>>> require that it be listed in the struts.xml file?
>>>>>>
>>>>>>
>>>>>> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <ka...@gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Thanks Wes,
>>>>>>>
>>>>>>> Appreciate such a prompt response.
>>>>>>>
>>>>>>> There are likely to be actions mapped via other means. There are
>>>>>>> many
>>>>>>>> plugins
>>>>>>>> available, most prominently the REST plugin and the Convention
>>>>>>>> plugin
>>>>>>>> that
>>>>>>>> allow our users to map actions without any XML
>>>>>>>>
>>>>>>>
>>>>>>> So a user would need these plugins to map actions without XML.
>>>>>>> Struts
>>>>>>> default behavior would require a user to map the action in the
>>>>>>> XML file
>>>>>>> and
>>>>>>> that would be struts.xml, right? So would it be fair to say that
>>>>>>> if I
>>>>>>> parse
>>>>>>> the struts.xml file and all included xml files, then I will have
>>>>>>> a list
>>>>>>> of
>>>>>>> all available actions in the webapp (assuming user is not using the
>>>>>>> plugins
>>>>>>> you mentioned) ?
>>>>>>>
>>>>>>>
>>>>>>>> 3. I was planning to write a plugin, but wanted to have access
>>>>>>>> to the
>>>>>>>>> ServletContext within the plugin. Could you show me how to do
>>>>>>>>> that -- I
>>>>>>>>> tried implementing ServletContextAware in the plugin class, but
>>>>>>>>> that
>>>>>>>>> did
>>>>>>>>> not work for me (maybe that interface is only supposed to be
>>>>>>>>> implemented
>>>>>>>>>
>>>>>>>> by
>>>>>>>>
>>>>>>>>> actions)
>>>>>>>>>
>>>>>>>> That interface is meant for actions. The best way to get a
>>>>>>>> ServletContext
>>>>>>>> is
>>>>>>>> to do the following from an interceptor -
>>>>>>>>
>>>>>>>> final ActionContext context = invocation.getInvocationContext();
>>>>>>>> ServletContext servletContext = (ServletContext)
>>>>>>>>
>>>>>>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>>>>>>
>>>>>>>> Although I did not manage to get access to the actual
>>>>>>>> ServletContext, I
>>>>>>> believe ActionContext.getContext().getApplication() would give me
>>>>>>> access
>>>>>>> to
>>>>>>> the Map of context attributes. Since I just need to read an
>>>>>>> attribute
>>>>>>> from
>>>>>>> it, I believe this approach should suffice.
>>>>>>>
>>>>>>> You may face a few issues though. I've thought briefly about EJB +
>>>>>>>> Struts2
>>>>>>>> lately and I'll admit to a lack of experience with EJB, but it
>>>>>>>> seems to
>>>>>>>> me
>>>>>>>> that it would be somewhat difficult to combine the two easily.
>>>>>>>> Many of
>>>>>>>> the
>>>>>>>> EJB
>>>>>>>> annotations can appear on private members (i.e.
>>>>>>>> @PersistenceContext). In
>>>>>>>> Struts2, we create actions via our own ObjectFactory, which can be
>>>>>>>> overridden
>>>>>>>> by a plugin.
>>>>>>>>
>>>>>>>> On application startup we collect information about all classes
>>>>>>>> which
>>>>>>> need
>>>>>>> injection. Then when instances of classes are created, we use that
>>>>>>> information to perform injection. The plugin which I wanted to write
>>>>>>> would
>>>>>>> be an ObjectFactory and I intended to override the buildBean
>>>>>>> method and
>>>>>>> perform the injection there. Actually, I just realized that I
>>>>>>> could get
>>>>>>> access to the Map of ServletContext attributes as shown below:
>>>>>>> public class OpenEJBObjectFactory extends ObjectFactory{
>>>>>>> public Object buildBean(Class clazz, Map map) throws Exception {
>>>>>>> Map application = (Map)map.get("application");
>>>>>>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>>>>>>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>>>>>>> }
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> I'm not particularly familiar with OpenEJB, but I'd like to help
>>>>>>> however
>>>>>>>> I
>>>>>>>> can. So, let me know if you need the help.
>>>>>>>>
>>>>>>>> Excellent. I really appreciate it. You are already helping in a
>>>>>>>> great
>>>>>>> way
>>>>>>> by answering my questions. Thank you so much.
>>>>>>>
>>>>>>> -Wes
>>>>>>>> --
>>>>>>>>
>>>>>>>> Wes Wannemacher
>>>>>>>> Author - Struts 2 In Practice
>>>>>>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh
>>>>>>>> and more
>>>>>>>> http://www.manning.com/wannemacher
>>>>>>>>
>>>>>>>>
>>>>>>>> ---------------------------------------------------------------------
>>>>>>>>
>>>>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>> --
>>>>>>> Karan Singh Malhi
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Karan Singh Malhi
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>> For additional commands, e-mail: dev-help@struts.apache.org
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>> For additional commands, e-mail: dev-help@struts.apache.org
>>
>>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
> For additional commands, e-mail: dev-help@struts.apache.org
>
--
René Gielen
IT-Neering.net
Saarstrasse 100, 52062 Aachen, Germany
Tel: +49-(0)241-4010770
Fax: +49-(0)241-4010771
Cel: +49-(0)177-3194448
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Re: EJB annotation support - was: [QUESTION]
Posted by Musachy Barroso <mu...@gmail.com>.
I am probably missing something here. Struts action mappings are
loaded when the app starts, and classes are scanned for annotations at
startup also.Only the action instantiation happens at request time,
depending on the Object Factory.
musachy
On Fri, Feb 27, 2009 at 9:56 PM, David Blevins <da...@visi.com> wrote:
>
> On Feb 27, 2009, at 12:11 AM, Rene Gielen wrote:
>
>> While ususally DI containers build up a complete configuration of known
>> beans at application startup, the pluggable DI container support for Struts2
>> works different. It is based on the assumption that each Action, Interceptor
>> and Validator will only need to get it's dependencies injected, but will
>> never be subject to being injected to other beans - which makes perfect
>> sense, since they are endpoints by design.
>>
>> If you look at how the ObjectFactory mechanism is implemented, you will
>> see that everything happens at runtime - the bean is created, and then
>> handled over to the DI container to have it scanned for injection candidates
>> (usually determined by a name or type strategy) and wired up based on the
>> configuration the container built at application startup. The
>> SpringObjectFactory in XWork gives a good overview on how this is solved.
>>
>> AFAICS this mechanism is also applicable to EJB- and Common-Annotations -
>> when ObjectFactory is requested to build a certain bean, scan it for it's
>> annotation configuration, optionally remember these results in a cache, and
>> have either the EJB container component do the wiring if it provides a
>> suitable extension point, or use a kind of active proxy to interpret he
>> annotations, ask the container for the needed resources, and wire the bean
>> up finally.
>
> That doesn't work so well for us in the current design. The code we have
> now more or less relies on knowing all the ejb, datasource, jms, env entry,
> persistence unit, persistence context, web service, and j2ee connector
> references up front so we can resolve them all, build the required
> infrastructure and objects for the app (entity managers, datasources,
> topics/queues, connection factories, orbs, mail sessions, web service
> handler chains and endpoints, connector resources), bind it all to jndi, and
> finally boot the app or report any errors or misuse of annotations.
>
> For at least the first iteration, it's going to be way easier to treat the
> struts objects the same as servlets or ejbs and scan them at app startup
> time.
>
> There are plenty of people who want more dynamic annotation processing
> (mostly to expand injection to test cases, plain clients, and misc java
> objects not managed by the container). If we had that code, it would
> definitely be useful in this situation. Might be something we can do down
> the road.
>
>
> -David
>
>>
>> David Blevins schrieb:
>>>
>>> On Feb 26, 2009, at 9:27 AM, Karan Malhi wrote:
>>>>
>>>> Thanks Rene. I am trying to avoid a situation where I would have to scan
>>>> the
>>>> whole classpath on web app startup. Does struts cache the information
>>>> about
>>>> all action classes somewhere?
>>>
>>> We actually do scan the entire webapp classpath for ejbs now. So it
>>> shouldn't be that bad.
>>> Though definitely if we can get that information from struts directly,
>>> even better. I wonder if there's a chicken and egg issue with that approach
>>> though. When exactly does struts do the searching? Right now we do all our
>>> scanning before the webapp starts up.
>>> -David
>>>>
>>>> On Tue, Feb 24, 2009 at 4:46 PM, Rene Gielen <gi...@it-neering.net>
>>>> wrote:
>>>>
>>>>> If your intent is to go for a ObjectFactory implementation / extension,
>>>>> I
>>>>> think it would not be necessary to distinct between action or
>>>>> non-action
>>>>> classes - just check the bean to build for the EJB annotations,
>>>>> regardless
>>>>> what kind of bean that is. Actually, in Struts2 not only action classes
>>>>> are
>>>>> candidates for an injection like this - interceptors would also be good
>>>>> candidates, maybe even results.
>>>>>
>>>>> I would really like to see "first class" EJB3 support in S2, and would
>>>>> also
>>>>> be glad to help where I can
>>>>>
>>>>> - Rene
>>>>>
>>>>> Karan Malhi schrieb:
>>>>>
>>>>> If a class has a suffix of Action or implements the Action interface,
>>>>> would
>>>>>>
>>>>>> that automatically be treated as an action class? Would such a class
>>>>>> require that it be listed in the struts.xml file?
>>>>>>
>>>>>>
>>>>>> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <ka...@gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Thanks Wes,
>>>>>>>
>>>>>>> Appreciate such a prompt response.
>>>>>>>
>>>>>>> There are likely to be actions mapped via other means. There are many
>>>>>>>>
>>>>>>>> plugins
>>>>>>>> available, most prominently the REST plugin and the Convention
>>>>>>>> plugin
>>>>>>>> that
>>>>>>>> allow our users to map actions without any XML
>>>>>>>>
>>>>>>>
>>>>>>> So a user would need these plugins to map actions without XML. Struts
>>>>>>> default behavior would require a user to map the action in the XML
>>>>>>> file
>>>>>>> and
>>>>>>> that would be struts.xml, right? So would it be fair to say that if I
>>>>>>> parse
>>>>>>> the struts.xml file and all included xml files, then I will have a
>>>>>>> list
>>>>>>> of
>>>>>>> all available actions in the webapp (assuming user is not using the
>>>>>>> plugins
>>>>>>> you mentioned) ?
>>>>>>>
>>>>>>>
>>>>>>>> 3. I was planning to write a plugin, but wanted to have access to
>>>>>>>> the
>>>>>>>>>
>>>>>>>>> ServletContext within the plugin. Could you show me how to do that
>>>>>>>>> -- I
>>>>>>>>> tried implementing ServletContextAware in the plugin class, but
>>>>>>>>> that
>>>>>>>>> did
>>>>>>>>> not work for me (maybe that interface is only supposed to be
>>>>>>>>> implemented
>>>>>>>>>
>>>>>>>> by
>>>>>>>>
>>>>>>>>> actions)
>>>>>>>>>
>>>>>>>> That interface is meant for actions. The best way to get a
>>>>>>>> ServletContext
>>>>>>>> is
>>>>>>>> to do the following from an interceptor -
>>>>>>>>
>>>>>>>> final ActionContext context = invocation.getInvocationContext();
>>>>>>>> ServletContext servletContext = (ServletContext)
>>>>>>>>
>>>>>>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>>>>>>
>>>>>>>> Although I did not manage to get access to the actual
>>>>>>>> ServletContext, I
>>>>>>>
>>>>>>> believe ActionContext.getContext().getApplication() would give me
>>>>>>> access
>>>>>>> to
>>>>>>> the Map of context attributes. Since I just need to read an
>>>>>>> attribute
>>>>>>> from
>>>>>>> it, I believe this approach should suffice.
>>>>>>>
>>>>>>> You may face a few issues though. I've thought briefly about EJB +
>>>>>>>>
>>>>>>>> Struts2
>>>>>>>> lately and I'll admit to a lack of experience with EJB, but it seems
>>>>>>>> to
>>>>>>>> me
>>>>>>>> that it would be somewhat difficult to combine the two easily. Many
>>>>>>>> of
>>>>>>>> the
>>>>>>>> EJB
>>>>>>>> annotations can appear on private members (i.e.
>>>>>>>> @PersistenceContext). In
>>>>>>>> Struts2, we create actions via our own ObjectFactory, which can be
>>>>>>>> overridden
>>>>>>>> by a plugin.
>>>>>>>>
>>>>>>>> On application startup we collect information about all classes
>>>>>>>> which
>>>>>>>
>>>>>>> need
>>>>>>> injection. Then when instances of classes are created, we use that
>>>>>>> information to perform injection. The plugin which I wanted to write
>>>>>>> would
>>>>>>> be an ObjectFactory and I intended to override the buildBean method
>>>>>>> and
>>>>>>> perform the injection there. Actually, I just realized that I could
>>>>>>> get
>>>>>>> access to the Map of ServletContext attributes as shown below:
>>>>>>> public class OpenEJBObjectFactory extends ObjectFactory{
>>>>>>> public Object buildBean(Class clazz, Map map) throws Exception {
>>>>>>> Map application = (Map)map.get("application");
>>>>>>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>>>>>>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>>>>>>> }
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> I'm not particularly familiar with OpenEJB, but I'd like to help
>>>>>>> however
>>>>>>>>
>>>>>>>> I
>>>>>>>> can. So, let me know if you need the help.
>>>>>>>>
>>>>>>>> Excellent. I really appreciate it. You are already helping in a
>>>>>>>> great
>>>>>>>
>>>>>>> way
>>>>>>> by answering my questions. Thank you so much.
>>>>>>>
>>>>>>> -Wes
>>>>>>>>
>>>>>>>> --
>>>>>>>>
>>>>>>>> Wes Wannemacher
>>>>>>>> Author - Struts 2 In Practice
>>>>>>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and
>>>>>>>> more
>>>>>>>> http://www.manning.com/wannemacher
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> ---------------------------------------------------------------------
>>>>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>> --
>>>>>>> Karan Singh Malhi
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Karan Singh Malhi
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>> For additional commands, e-mail: dev-help@struts.apache.org
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>> For additional commands, e-mail: dev-help@struts.apache.org
>>
>>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
> For additional commands, e-mail: dev-help@struts.apache.org
>
>
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"Hey you! Would you help me to carry the stone?" Pink Floyd
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Re: EJB annotation support - was: [QUESTION]
Posted by David Blevins <da...@visi.com>.
On Feb 27, 2009, at 12:11 AM, Rene Gielen wrote:
> While ususally DI containers build up a complete configuration of
> known beans at application startup, the pluggable DI container
> support for Struts2 works different. It is based on the assumption
> that each Action, Interceptor and Validator will only need to get
> it's dependencies injected, but will never be subject to being
> injected to other beans - which makes perfect sense, since they are
> endpoints by design.
>
> If you look at how the ObjectFactory mechanism is implemented, you
> will see that everything happens at runtime - the bean is created,
> and then handled over to the DI container to have it scanned for
> injection candidates (usually determined by a name or type strategy)
> and wired up based on the configuration the container built at
> application startup. The SpringObjectFactory in XWork gives a good
> overview on how this is solved.
>
> AFAICS this mechanism is also applicable to EJB- and Common-
> Annotations - when ObjectFactory is requested to build a certain
> bean, scan it for it's annotation configuration, optionally remember
> these results in a cache, and have either the EJB container
> component do the wiring if it provides a suitable extension point,
> or use a kind of active proxy to interpret he annotations, ask the
> container for the needed resources, and wire the bean up finally.
That doesn't work so well for us in the current design. The code we
have now more or less relies on knowing all the ejb, datasource, jms,
env entry, persistence unit, persistence context, web service, and
j2ee connector references up front so we can resolve them all, build
the required infrastructure and objects for the app (entity managers,
datasources, topics/queues, connection factories, orbs, mail sessions,
web service handler chains and endpoints, connector resources), bind
it all to jndi, and finally boot the app or report any errors or
misuse of annotations.
For at least the first iteration, it's going to be way easier to treat
the struts objects the same as servlets or ejbs and scan them at app
startup time.
There are plenty of people who want more dynamic annotation processing
(mostly to expand injection to test cases, plain clients, and misc
java objects not managed by the container). If we had that code, it
would definitely be useful in this situation. Might be something we
can do down the road.
-David
>
> David Blevins schrieb:
>> On Feb 26, 2009, at 9:27 AM, Karan Malhi wrote:
>>> Thanks Rene. I am trying to avoid a situation where I would have
>>> to scan the
>>> whole classpath on web app startup. Does struts cache the
>>> information about
>>> all action classes somewhere?
>> We actually do scan the entire webapp classpath for ejbs now. So
>> it shouldn't be that bad.
>> Though definitely if we can get that information from struts
>> directly, even better. I wonder if there's a chicken and egg issue
>> with that approach though. When exactly does struts do the
>> searching? Right now we do all our scanning before the webapp
>> starts up.
>> -David
>>> On Tue, Feb 24, 2009 at 4:46 PM, Rene Gielen <gielen@it-
>>> neering.net> wrote:
>>>
>>>> If your intent is to go for a ObjectFactory implementation /
>>>> extension, I
>>>> think it would not be necessary to distinct between action or non-
>>>> action
>>>> classes - just check the bean to build for the EJB annotations,
>>>> regardless
>>>> what kind of bean that is. Actually, in Struts2 not only action
>>>> classes are
>>>> candidates for an injection like this - interceptors would also
>>>> be good
>>>> candidates, maybe even results.
>>>>
>>>> I would really like to see "first class" EJB3 support in S2, and
>>>> would also
>>>> be glad to help where I can
>>>>
>>>> - Rene
>>>>
>>>> Karan Malhi schrieb:
>>>>
>>>> If a class has a suffix of Action or implements the Action
>>>> interface, would
>>>>> that automatically be treated as an action class? Would such a
>>>>> class
>>>>> require that it be listed in the struts.xml file?
>>>>>
>>>>>
>>>>> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <karan.malhi@gmail.com
>>>>> >
>>>>> wrote:
>>>>>
>>>>> Thanks Wes,
>>>>>>
>>>>>> Appreciate such a prompt response.
>>>>>>
>>>>>> There are likely to be actions mapped via other means. There
>>>>>> are many
>>>>>>> plugins
>>>>>>> available, most prominently the REST plugin and the Convention
>>>>>>> plugin
>>>>>>> that
>>>>>>> allow our users to map actions without any XML
>>>>>>>
>>>>>>
>>>>>> So a user would need these plugins to map actions without XML.
>>>>>> Struts
>>>>>> default behavior would require a user to map the action in the
>>>>>> XML file
>>>>>> and
>>>>>> that would be struts.xml, right? So would it be fair to say
>>>>>> that if I
>>>>>> parse
>>>>>> the struts.xml file and all included xml files, then I will
>>>>>> have a list
>>>>>> of
>>>>>> all available actions in the webapp (assuming user is not using
>>>>>> the
>>>>>> plugins
>>>>>> you mentioned) ?
>>>>>>
>>>>>>
>>>>>>> 3. I was planning to write a plugin, but wanted to have access
>>>>>>> to the
>>>>>>>> ServletContext within the plugin. Could you show me how to do
>>>>>>>> that -- I
>>>>>>>> tried implementing ServletContextAware in the plugin class,
>>>>>>>> but that
>>>>>>>> did
>>>>>>>> not work for me (maybe that interface is only supposed to be
>>>>>>>> implemented
>>>>>>>>
>>>>>>> by
>>>>>>>
>>>>>>>> actions)
>>>>>>>>
>>>>>>> That interface is meant for actions. The best way to get a
>>>>>>> ServletContext
>>>>>>> is
>>>>>>> to do the following from an interceptor -
>>>>>>>
>>>>>>> final ActionContext context = invocation.getInvocationContext();
>>>>>>> ServletContext servletContext = (ServletContext)
>>>>>>>
>>>>>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>>>>>
>>>>>>> Although I did not manage to get access to the actual
>>>>>>> ServletContext, I
>>>>>> believe ActionContext.getContext().getApplication() would give
>>>>>> me access
>>>>>> to
>>>>>> the Map of context attributes. Since I just need to read an
>>>>>> attribute
>>>>>> from
>>>>>> it, I believe this approach should suffice.
>>>>>>
>>>>>> You may face a few issues though. I've thought briefly about
>>>>>> EJB +
>>>>>>> Struts2
>>>>>>> lately and I'll admit to a lack of experience with EJB, but it
>>>>>>> seems to
>>>>>>> me
>>>>>>> that it would be somewhat difficult to combine the two easily.
>>>>>>> Many of
>>>>>>> the
>>>>>>> EJB
>>>>>>> annotations can appear on private members (i.e.
>>>>>>> @PersistenceContext). In
>>>>>>> Struts2, we create actions via our own ObjectFactory, which
>>>>>>> can be
>>>>>>> overridden
>>>>>>> by a plugin.
>>>>>>>
>>>>>>> On application startup we collect information about all
>>>>>>> classes which
>>>>>> need
>>>>>> injection. Then when instances of classes are created, we use
>>>>>> that
>>>>>> information to perform injection. The plugin which I wanted to
>>>>>> write
>>>>>> would
>>>>>> be an ObjectFactory and I intended to override the buildBean
>>>>>> method and
>>>>>> perform the injection there. Actually, I just realized that I
>>>>>> could get
>>>>>> access to the Map of ServletContext attributes as shown below:
>>>>>> public class OpenEJBObjectFactory extends ObjectFactory{
>>>>>> public Object buildBean(Class clazz, Map map) throws Exception {
>>>>>> Map application = (Map)map.get("application");
>>>>>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>>>>>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>>>>>> }
>>>>>> }
>>>>>>
>>>>>>
>>>>>> I'm not particularly familiar with OpenEJB, but I'd like to
>>>>>> help however
>>>>>>> I
>>>>>>> can. So, let me know if you need the help.
>>>>>>>
>>>>>>> Excellent. I really appreciate it. You are already helping in
>>>>>>> a great
>>>>>> way
>>>>>> by answering my questions. Thank you so much.
>>>>>>
>>>>>> -Wes
>>>>>>> --
>>>>>>>
>>>>>>> Wes Wannemacher
>>>>>>> Author - Struts 2 In Practice
>>>>>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh
>>>>>>> and more
>>>>>>> http://www.manning.com/wannemacher
>>>>>>>
>>>>>>>
>>>>>>> ---------------------------------------------------------------------
>>>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> --
>>>>>> Karan Singh Malhi
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>
>>>>
>>>
>>>
>>> --
>>> Karan Singh Malhi
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>> For additional commands, e-mail: dev-help@struts.apache.org
>
> ---------------------------------------------------------------------
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> For additional commands, e-mail: dev-help@struts.apache.org
>
>
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Re: EJB annotation support - was: [QUESTION]
Posted by Rene Gielen <gi...@it-neering.net>.
While ususally DI containers build up a complete configuration of known
beans at application startup, the pluggable DI container support for
Struts2 works different. It is based on the assumption that each Action,
Interceptor and Validator will only need to get it's dependencies
injected, but will never be subject to being injected to other beans -
which makes perfect sense, since they are endpoints by design.
If you look at how the ObjectFactory mechanism is implemented, you will
see that everything happens at runtime - the bean is created, and then
handled over to the DI container to have it scanned for injection
candidates (usually determined by a name or type strategy) and wired up
based on the configuration the container built at application startup.
The SpringObjectFactory in XWork gives a good overview on how this is
solved.
AFAICS this mechanism is also applicable to EJB- and Common-Annotations
- when ObjectFactory is requested to build a certain bean, scan it for
it's annotation configuration, optionally remember these results in a
cache, and have either the EJB container component do the wiring if it
provides a suitable extension point, or use a kind of active proxy to
interpret he annotations, ask the container for the needed resources,
and wire the bean up finally.
- Rene
David Blevins schrieb:
>
> On Feb 26, 2009, at 9:27 AM, Karan Malhi wrote:
>
>> Thanks Rene. I am trying to avoid a situation where I would have to
>> scan the
>> whole classpath on web app startup. Does struts cache the information
>> about
>> all action classes somewhere?
>
> We actually do scan the entire webapp classpath for ejbs now. So it
> shouldn't be that bad.
>
> Though definitely if we can get that information from struts directly,
> even better. I wonder if there's a chicken and egg issue with that
> approach though. When exactly does struts do the searching? Right now
> we do all our scanning before the webapp starts up.
>
> -David
>
>
>> On Tue, Feb 24, 2009 at 4:46 PM, Rene Gielen <gi...@it-neering.net>
>> wrote:
>>
>>> If your intent is to go for a ObjectFactory implementation /
>>> extension, I
>>> think it would not be necessary to distinct between action or non-action
>>> classes - just check the bean to build for the EJB annotations,
>>> regardless
>>> what kind of bean that is. Actually, in Struts2 not only action
>>> classes are
>>> candidates for an injection like this - interceptors would also be good
>>> candidates, maybe even results.
>>>
>>> I would really like to see "first class" EJB3 support in S2, and
>>> would also
>>> be glad to help where I can
>>>
>>> - Rene
>>>
>>> Karan Malhi schrieb:
>>>
>>> If a class has a suffix of Action or implements the Action interface,
>>> would
>>>> that automatically be treated as an action class? Would such a class
>>>> require that it be listed in the struts.xml file?
>>>>
>>>>
>>>> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <ka...@gmail.com>
>>>> wrote:
>>>>
>>>> Thanks Wes,
>>>>>
>>>>> Appreciate such a prompt response.
>>>>>
>>>>> There are likely to be actions mapped via other means. There are many
>>>>>> plugins
>>>>>> available, most prominently the REST plugin and the Convention plugin
>>>>>> that
>>>>>> allow our users to map actions without any XML
>>>>>>
>>>>>
>>>>> So a user would need these plugins to map actions without XML. Struts
>>>>> default behavior would require a user to map the action in the XML
>>>>> file
>>>>> and
>>>>> that would be struts.xml, right? So would it be fair to say that if I
>>>>> parse
>>>>> the struts.xml file and all included xml files, then I will have a
>>>>> list
>>>>> of
>>>>> all available actions in the webapp (assuming user is not using the
>>>>> plugins
>>>>> you mentioned) ?
>>>>>
>>>>>
>>>>>> 3. I was planning to write a plugin, but wanted to have access to the
>>>>>>> ServletContext within the plugin. Could you show me how to do
>>>>>>> that -- I
>>>>>>> tried implementing ServletContextAware in the plugin class, but that
>>>>>>> did
>>>>>>> not work for me (maybe that interface is only supposed to be
>>>>>>> implemented
>>>>>>>
>>>>>> by
>>>>>>
>>>>>>> actions)
>>>>>>>
>>>>>> That interface is meant for actions. The best way to get a
>>>>>> ServletContext
>>>>>> is
>>>>>> to do the following from an interceptor -
>>>>>>
>>>>>> final ActionContext context = invocation.getInvocationContext();
>>>>>> ServletContext servletContext = (ServletContext)
>>>>>>
>>>>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>>>>
>>>>>> Although I did not manage to get access to the actual
>>>>>> ServletContext, I
>>>>> believe ActionContext.getContext().getApplication() would give me
>>>>> access
>>>>> to
>>>>> the Map of context attributes. Since I just need to read an attribute
>>>>> from
>>>>> it, I believe this approach should suffice.
>>>>>
>>>>> You may face a few issues though. I've thought briefly about EJB +
>>>>>> Struts2
>>>>>> lately and I'll admit to a lack of experience with EJB, but it
>>>>>> seems to
>>>>>> me
>>>>>> that it would be somewhat difficult to combine the two easily.
>>>>>> Many of
>>>>>> the
>>>>>> EJB
>>>>>> annotations can appear on private members (i.e.
>>>>>> @PersistenceContext). In
>>>>>> Struts2, we create actions via our own ObjectFactory, which can be
>>>>>> overridden
>>>>>> by a plugin.
>>>>>>
>>>>>> On application startup we collect information about all classes which
>>>>> need
>>>>> injection. Then when instances of classes are created, we use that
>>>>> information to perform injection. The plugin which I wanted to write
>>>>> would
>>>>> be an ObjectFactory and I intended to override the buildBean method
>>>>> and
>>>>> perform the injection there. Actually, I just realized that I could
>>>>> get
>>>>> access to the Map of ServletContext attributes as shown below:
>>>>> public class OpenEJBObjectFactory extends ObjectFactory{
>>>>> public Object buildBean(Class clazz, Map map) throws Exception {
>>>>> Map application = (Map)map.get("application");
>>>>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>>>>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>>>>> }
>>>>> }
>>>>>
>>>>>
>>>>> I'm not particularly familiar with OpenEJB, but I'd like to help
>>>>> however
>>>>>> I
>>>>>> can. So, let me know if you need the help.
>>>>>>
>>>>>> Excellent. I really appreciate it. You are already helping in a great
>>>>> way
>>>>> by answering my questions. Thank you so much.
>>>>>
>>>>> -Wes
>>>>>> --
>>>>>>
>>>>>> Wes Wannemacher
>>>>>> Author - Struts 2 In Practice
>>>>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and
>>>>>> more
>>>>>> http://www.manning.com/wannemacher
>>>>>>
>>>>>>
>>>>>> ---------------------------------------------------------------------
>>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>>
>>>>>>
>>>>>>
>>>>> --
>>>>> Karan Singh Malhi
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>
>>>
>>
>>
>> --
>> Karan Singh Malhi
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
> For additional commands, e-mail: dev-help@struts.apache.org
>
---------------------------------------------------------------------
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Re: [QUESTION]
Posted by David Blevins <da...@visi.com>.
On Feb 26, 2009, at 9:27 AM, Karan Malhi wrote:
> Thanks Rene. I am trying to avoid a situation where I would have to
> scan the
> whole classpath on web app startup. Does struts cache the
> information about
> all action classes somewhere?
We actually do scan the entire webapp classpath for ejbs now. So it
shouldn't be that bad.
Though definitely if we can get that information from struts directly,
even better. I wonder if there's a chicken and egg issue with that
approach though. When exactly does struts do the searching? Right
now we do all our scanning before the webapp starts up.
-David
> On Tue, Feb 24, 2009 at 4:46 PM, Rene Gielen <gi...@it-neering.net>
> wrote:
>
>> If your intent is to go for a ObjectFactory implementation /
>> extension, I
>> think it would not be necessary to distinct between action or non-
>> action
>> classes - just check the bean to build for the EJB annotations,
>> regardless
>> what kind of bean that is. Actually, in Struts2 not only action
>> classes are
>> candidates for an injection like this - interceptors would also be
>> good
>> candidates, maybe even results.
>>
>> I would really like to see "first class" EJB3 support in S2, and
>> would also
>> be glad to help where I can
>>
>> - Rene
>>
>> Karan Malhi schrieb:
>>
>> If a class has a suffix of Action or implements the Action
>> interface, would
>>> that automatically be treated as an action class? Would such a
>>> class
>>> require that it be listed in the struts.xml file?
>>>
>>>
>>> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi
>>> <ka...@gmail.com>
>>> wrote:
>>>
>>> Thanks Wes,
>>>>
>>>> Appreciate such a prompt response.
>>>>
>>>> There are likely to be actions mapped via other means. There are
>>>> many
>>>>> plugins
>>>>> available, most prominently the REST plugin and the Convention
>>>>> plugin
>>>>> that
>>>>> allow our users to map actions without any XML
>>>>>
>>>>
>>>> So a user would need these plugins to map actions without XML.
>>>> Struts
>>>> default behavior would require a user to map the action in the
>>>> XML file
>>>> and
>>>> that would be struts.xml, right? So would it be fair to say that
>>>> if I
>>>> parse
>>>> the struts.xml file and all included xml files, then I will have
>>>> a list
>>>> of
>>>> all available actions in the webapp (assuming user is not using the
>>>> plugins
>>>> you mentioned) ?
>>>>
>>>>
>>>>> 3. I was planning to write a plugin, but wanted to have access
>>>>> to the
>>>>>> ServletContext within the plugin. Could you show me how to do
>>>>>> that -- I
>>>>>> tried implementing ServletContextAware in the plugin class, but
>>>>>> that
>>>>>> did
>>>>>> not work for me (maybe that interface is only supposed to be
>>>>>> implemented
>>>>>>
>>>>> by
>>>>>
>>>>>> actions)
>>>>>>
>>>>> That interface is meant for actions. The best way to get a
>>>>> ServletContext
>>>>> is
>>>>> to do the following from an interceptor -
>>>>>
>>>>> final ActionContext context = invocation.getInvocationContext();
>>>>> ServletContext servletContext = (ServletContext)
>>>>>
>>>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>>>
>>>>> Although I did not manage to get access to the actual
>>>>> ServletContext, I
>>>> believe ActionContext.getContext().getApplication() would give me
>>>> access
>>>> to
>>>> the Map of context attributes. Since I just need to read an
>>>> attribute
>>>> from
>>>> it, I believe this approach should suffice.
>>>>
>>>> You may face a few issues though. I've thought briefly about EJB +
>>>>> Struts2
>>>>> lately and I'll admit to a lack of experience with EJB, but it
>>>>> seems to
>>>>> me
>>>>> that it would be somewhat difficult to combine the two easily.
>>>>> Many of
>>>>> the
>>>>> EJB
>>>>> annotations can appear on private members (i.e.
>>>>> @PersistenceContext). In
>>>>> Struts2, we create actions via our own ObjectFactory, which can be
>>>>> overridden
>>>>> by a plugin.
>>>>>
>>>>> On application startup we collect information about all classes
>>>>> which
>>>> need
>>>> injection. Then when instances of classes are created, we use that
>>>> information to perform injection. The plugin which I wanted to
>>>> write
>>>> would
>>>> be an ObjectFactory and I intended to override the buildBean
>>>> method and
>>>> perform the injection there. Actually, I just realized that I
>>>> could get
>>>> access to the Map of ServletContext attributes as shown below:
>>>> public class OpenEJBObjectFactory extends ObjectFactory{
>>>> public Object buildBean(Class clazz, Map map) throws Exception {
>>>> Map application = (Map)map.get("application");
>>>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>>>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>>>> }
>>>> }
>>>>
>>>>
>>>> I'm not particularly familiar with OpenEJB, but I'd like to help
>>>> however
>>>>> I
>>>>> can. So, let me know if you need the help.
>>>>>
>>>>> Excellent. I really appreciate it. You are already helping in a
>>>>> great
>>>> way
>>>> by answering my questions. Thank you so much.
>>>>
>>>> -Wes
>>>>> --
>>>>>
>>>>> Wes Wannemacher
>>>>> Author - Struts 2 In Practice
>>>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh
>>>>> and more
>>>>> http://www.manning.com/wannemacher
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>>
>>>>>
>>>>>
>>>> --
>>>> Karan Singh Malhi
>>>>
>>>>
>>>
>>>
>>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>> For additional commands, e-mail: dev-help@struts.apache.org
>>
>>
>
>
> --
> Karan Singh Malhi
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
For additional commands, e-mail: dev-help@struts.apache.org
Re: [QUESTION]
Posted by Karan Malhi <ka...@gmail.com>.
Thanks Rene. I am trying to avoid a situation where I would have to scan the
whole classpath on web app startup. Does struts cache the information about
all action classes somewhere? I am thinking maybe I could simply use that
information , instead of trying to figure out the action classes on my own?
On Tue, Feb 24, 2009 at 4:46 PM, Rene Gielen <gi...@it-neering.net> wrote:
> If your intent is to go for a ObjectFactory implementation / extension, I
> think it would not be necessary to distinct between action or non-action
> classes - just check the bean to build for the EJB annotations, regardless
> what kind of bean that is. Actually, in Struts2 not only action classes are
> candidates for an injection like this - interceptors would also be good
> candidates, maybe even results.
>
> I would really like to see "first class" EJB3 support in S2, and would also
> be glad to help where I can
>
> - Rene
>
> Karan Malhi schrieb:
>
> If a class has a suffix of Action or implements the Action interface, would
>> that automatically be treated as an action class? Would such a class
>> require that it be listed in the struts.xml file?
>>
>>
>> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <ka...@gmail.com>
>> wrote:
>>
>> Thanks Wes,
>>>
>>> Appreciate such a prompt response.
>>>
>>> There are likely to be actions mapped via other means. There are many
>>>> plugins
>>>> available, most prominently the REST plugin and the Convention plugin
>>>> that
>>>> allow our users to map actions without any XML
>>>>
>>>
>>> So a user would need these plugins to map actions without XML. Struts
>>> default behavior would require a user to map the action in the XML file
>>> and
>>> that would be struts.xml, right? So would it be fair to say that if I
>>> parse
>>> the struts.xml file and all included xml files, then I will have a list
>>> of
>>> all available actions in the webapp (assuming user is not using the
>>> plugins
>>> you mentioned) ?
>>>
>>>
>>>> 3. I was planning to write a plugin, but wanted to have access to the
>>>>> ServletContext within the plugin. Could you show me how to do that -- I
>>>>> tried implementing ServletContextAware in the plugin class, but that
>>>>> did
>>>>> not work for me (maybe that interface is only supposed to be
>>>>> implemented
>>>>>
>>>> by
>>>>
>>>>> actions)
>>>>>
>>>> That interface is meant for actions. The best way to get a
>>>> ServletContext
>>>> is
>>>> to do the following from an interceptor -
>>>>
>>>> final ActionContext context = invocation.getInvocationContext();
>>>> ServletContext servletContext = (ServletContext)
>>>>
>>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>>
>>>> Although I did not manage to get access to the actual ServletContext, I
>>> believe ActionContext.getContext().getApplication() would give me access
>>> to
>>> the Map of context attributes. Since I just need to read an attribute
>>> from
>>> it, I believe this approach should suffice.
>>>
>>> You may face a few issues though. I've thought briefly about EJB +
>>>> Struts2
>>>> lately and I'll admit to a lack of experience with EJB, but it seems to
>>>> me
>>>> that it would be somewhat difficult to combine the two easily. Many of
>>>> the
>>>> EJB
>>>> annotations can appear on private members (i.e. @PersistenceContext). In
>>>> Struts2, we create actions via our own ObjectFactory, which can be
>>>> overridden
>>>> by a plugin.
>>>>
>>>> On application startup we collect information about all classes which
>>> need
>>> injection. Then when instances of classes are created, we use that
>>> information to perform injection. The plugin which I wanted to write
>>> would
>>> be an ObjectFactory and I intended to override the buildBean method and
>>> perform the injection there. Actually, I just realized that I could get
>>> access to the Map of ServletContext attributes as shown below:
>>> public class OpenEJBObjectFactory extends ObjectFactory{
>>> public Object buildBean(Class clazz, Map map) throws Exception {
>>> Map application = (Map)map.get("application");
>>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>>> }
>>> }
>>>
>>>
>>> I'm not particularly familiar with OpenEJB, but I'd like to help however
>>>> I
>>>> can. So, let me know if you need the help.
>>>>
>>>> Excellent. I really appreciate it. You are already helping in a great
>>> way
>>> by answering my questions. Thank you so much.
>>>
>>> -Wes
>>>> --
>>>>
>>>> Wes Wannemacher
>>>> Author - Struts 2 In Practice
>>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
>>>> http://www.manning.com/wannemacher
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>>
>>>>
>>>>
>>> --
>>> Karan Singh Malhi
>>>
>>>
>>
>>
>>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
> For additional commands, e-mail: dev-help@struts.apache.org
>
>
--
Karan Singh Malhi
Re: [QUESTION]
Posted by Rene Gielen <gi...@it-neering.net>.
If your intent is to go for a ObjectFactory implementation / extension,
I think it would not be necessary to distinct between action or
non-action classes - just check the bean to build for the EJB
annotations, regardless what kind of bean that is. Actually, in Struts2
not only action classes are candidates for an injection like this -
interceptors would also be good candidates, maybe even results.
I would really like to see "first class" EJB3 support in S2, and would
also be glad to help where I can
- Rene
Karan Malhi schrieb:
> If a class has a suffix of Action or implements the Action interface, would
> that automatically be treated as an action class? Would such a class
> require that it be listed in the struts.xml file?
>
>
> On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <ka...@gmail.com> wrote:
>
>> Thanks Wes,
>>
>> Appreciate such a prompt response.
>>
>>> There are likely to be actions mapped via other means. There are many
>>> plugins
>>> available, most prominently the REST plugin and the Convention plugin that
>>> allow our users to map actions without any XML
>>
>> So a user would need these plugins to map actions without XML. Struts
>> default behavior would require a user to map the action in the XML file and
>> that would be struts.xml, right? So would it be fair to say that if I parse
>> the struts.xml file and all included xml files, then I will have a list of
>> all available actions in the webapp (assuming user is not using the plugins
>> you mentioned) ?
>>
>>>
>>>> 3. I was planning to write a plugin, but wanted to have access to the
>>>> ServletContext within the plugin. Could you show me how to do that -- I
>>>> tried implementing ServletContextAware in the plugin class, but that did
>>>> not work for me (maybe that interface is only supposed to be implemented
>>> by
>>>> actions)
>>> That interface is meant for actions. The best way to get a ServletContext
>>> is
>>> to do the following from an interceptor -
>>>
>>> final ActionContext context = invocation.getInvocationContext();
>>> ServletContext servletContext = (ServletContext)
>>>
>>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>>
>> Although I did not manage to get access to the actual ServletContext, I
>> believe ActionContext.getContext().getApplication() would give me access to
>> the Map of context attributes. Since I just need to read an attribute from
>> it, I believe this approach should suffice.
>>
>>> You may face a few issues though. I've thought briefly about EJB + Struts2
>>> lately and I'll admit to a lack of experience with EJB, but it seems to me
>>> that it would be somewhat difficult to combine the two easily. Many of the
>>> EJB
>>> annotations can appear on private members (i.e. @PersistenceContext). In
>>> Struts2, we create actions via our own ObjectFactory, which can be
>>> overridden
>>> by a plugin.
>>>
>> On application startup we collect information about all classes which need
>> injection. Then when instances of classes are created, we use that
>> information to perform injection. The plugin which I wanted to write would
>> be an ObjectFactory and I intended to override the buildBean method and
>> perform the injection there. Actually, I just realized that I could get
>> access to the Map of ServletContext attributes as shown below:
>> public class OpenEJBObjectFactory extends ObjectFactory{
>> public Object buildBean(Class clazz, Map map) throws Exception {
>> Map application = (Map)map.get("application");
>> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
>> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
>> }
>> }
>>
>>
>>> I'm not particularly familiar with OpenEJB, but I'd like to help however I
>>> can. So, let me know if you need the help.
>>>
>> Excellent. I really appreciate it. You are already helping in a great way
>> by answering my questions. Thank you so much.
>>
>>> -Wes
>>> --
>>>
>>> Wes Wannemacher
>>> Author - Struts 2 In Practice
>>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
>>> http://www.manning.com/wannemacher
>>>
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>>> For additional commands, e-mail: dev-help@struts.apache.org
>>>
>>>
>>
>> --
>> Karan Singh Malhi
>>
>
>
>
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Re: [QUESTION]
Posted by Karan Malhi <ka...@gmail.com>.
If a class has a suffix of Action or implements the Action interface, would
that automatically be treated as an action class? Would such a class
require that it be listed in the struts.xml file?
On Sat, Feb 21, 2009 at 11:29 PM, Karan Malhi <ka...@gmail.com> wrote:
> Thanks Wes,
>
> Appreciate such a prompt response.
>
>>
>> There are likely to be actions mapped via other means. There are many
>> plugins
>> available, most prominently the REST plugin and the Convention plugin that
>> allow our users to map actions without any XML
>
>
> So a user would need these plugins to map actions without XML. Struts
> default behavior would require a user to map the action in the XML file and
> that would be struts.xml, right? So would it be fair to say that if I parse
> the struts.xml file and all included xml files, then I will have a list of
> all available actions in the webapp (assuming user is not using the plugins
> you mentioned) ?
>
>>
>>
>> > 3. I was planning to write a plugin, but wanted to have access to the
>> > ServletContext within the plugin. Could you show me how to do that -- I
>> > tried implementing ServletContextAware in the plugin class, but that did
>> > not work for me (maybe that interface is only supposed to be implemented
>> by
>> > actions)
>>
>> That interface is meant for actions. The best way to get a ServletContext
>> is
>> to do the following from an interceptor -
>>
>> final ActionContext context = invocation.getInvocationContext();
>> ServletContext servletContext = (ServletContext)
>>
>> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>>
>
> Although I did not manage to get access to the actual ServletContext, I
> believe ActionContext.getContext().getApplication() would give me access to
> the Map of context attributes. Since I just need to read an attribute from
> it, I believe this approach should suffice.
>
>>
>> You may face a few issues though. I've thought briefly about EJB + Struts2
>> lately and I'll admit to a lack of experience with EJB, but it seems to me
>> that it would be somewhat difficult to combine the two easily. Many of the
>> EJB
>> annotations can appear on private members (i.e. @PersistenceContext). In
>> Struts2, we create actions via our own ObjectFactory, which can be
>> overridden
>> by a plugin.
>>
> On application startup we collect information about all classes which need
> injection. Then when instances of classes are created, we use that
> information to perform injection. The plugin which I wanted to write would
> be an ObjectFactory and I intended to override the buildBean method and
> perform the injection there. Actually, I just realized that I could get
> access to the Map of ServletContext attributes as shown below:
> public class OpenEJBObjectFactory extends ObjectFactory{
> public Object buildBean(Class clazz, Map map) throws Exception {
> Map application = (Map)map.get("application");
> // THIS IS WHERE I COULD READ THE ATTRIBUTE AND
> // CREATE THE ACTION INSTANCE AND PERFORM INJECTION
> }
> }
>
>
>>
>> I'm not particularly familiar with OpenEJB, but I'd like to help however I
>> can. So, let me know if you need the help.
>>
> Excellent. I really appreciate it. You are already helping in a great way
> by answering my questions. Thank you so much.
>
>>
>> -Wes
>> --
>>
>> Wes Wannemacher
>> Author - Struts 2 In Practice
>> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
>> http://www.manning.com/wannemacher
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
>> For additional commands, e-mail: dev-help@struts.apache.org
>>
>>
>
>
> --
> Karan Singh Malhi
>
--
Karan Singh Malhi
Re: [QUESTION]
Posted by Karan Malhi <ka...@gmail.com>.
Thanks Wes,
Appreciate such a prompt response.
>
> There are likely to be actions mapped via other means. There are many
> plugins
> available, most prominently the REST plugin and the Convention plugin that
> allow our users to map actions without any XML
So a user would need these plugins to map actions without XML. Struts
default behavior would require a user to map the action in the XML file and
that would be struts.xml, right? So would it be fair to say that if I parse
the struts.xml file and all included xml files, then I will have a list of
all available actions in the webapp (assuming user is not using the plugins
you mentioned) ?
>
>
> > 3. I was planning to write a plugin, but wanted to have access to the
> > ServletContext within the plugin. Could you show me how to do that -- I
> > tried implementing ServletContextAware in the plugin class, but that did
> > not work for me (maybe that interface is only supposed to be implemented
> by
> > actions)
>
> That interface is meant for actions. The best way to get a ServletContext
> is
> to do the following from an interceptor -
>
> final ActionContext context = invocation.getInvocationContext();
> ServletContext servletContext = (ServletContext)
>
> context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
>
Although I did not manage to get access to the actual ServletContext, I
believe ActionContext.getContext().getApplication() would give me access to
the Map of context attributes. Since I just need to read an attribute from
it, I believe this approach should suffice.
>
> You may face a few issues though. I've thought briefly about EJB + Struts2
> lately and I'll admit to a lack of experience with EJB, but it seems to me
> that it would be somewhat difficult to combine the two easily. Many of the
> EJB
> annotations can appear on private members (i.e. @PersistenceContext). In
> Struts2, we create actions via our own ObjectFactory, which can be
> overridden
> by a plugin.
>
On application startup we collect information about all classes which need
injection. Then when instances of classes are created, we use that
information to perform injection. The plugin which I wanted to write would
be an ObjectFactory and I intended to override the buildBean method and
perform the injection there. Actually, I just realized that I could get
access to the Map of ServletContext attributes as shown below:
public class OpenEJBObjectFactory extends ObjectFactory{
public Object buildBean(Class clazz, Map map) throws Exception {
Map application = (Map)map.get("application");
// THIS IS WHERE I COULD READ THE ATTRIBUTE AND
// CREATE THE ACTION INSTANCE AND PERFORM INJECTION
}
}
>
> I'm not particularly familiar with OpenEJB, but I'd like to help however I
> can. So, let me know if you need the help.
>
Excellent. I really appreciate it. You are already helping in a great way by
answering my questions. Thank you so much.
>
> -Wes
> --
>
> Wes Wannemacher
> Author - Struts 2 In Practice
> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
> http://www.manning.com/wannemacher
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@struts.apache.org
> For additional commands, e-mail: dev-help@struts.apache.org
>
>
--
Karan Singh Malhi
Re: [QUESTION]
Posted by Wes Wannemacher <we...@wantii.com>.
On Saturday 21 February 2009 22:44:28 Karan Malhi wrote:
> Hi,
>
> I work on the OpenEJB project. I wanted to add support for injecting
> resources into struts actions i.e. if somebody creates a struts based web
> app and deploys it in Tomcat + OpenEJB, then I want the user to be able to
> annotate the struts actions with @EJB, @Resource etc and then have OpenEJB
> inject those resources. To do that, I need to find out which classes in the
> web-app represent actions. Initially I thought that struts.xml would
> contain all the Action classes (listed as part of action elements). Then I
> found out that one could also include other xml files within struts xml
> using the <include/> element. Since I do not know struts 2 that well, I
> have a few questions which will help me a long way to add injection
> support:- 1. Does the struts config files has to be named struts.xml or can
> it be named something else? If yes, how would struts discover such a file?
> 2. Are all actions mapped in struts.xml and the included xml files (using
> the include element) or there could be actions which do not need to be
> listed in these xml files.
There are likely to be actions mapped via other means. There are many plugins
available, most prominently the REST plugin and the Convention plugin that
allow our users to map actions without any XML
> 3. I was planning to write a plugin, but wanted to have access to the
> ServletContext within the plugin. Could you show me how to do that -- I
> tried implementing ServletContextAware in the plugin class, but that did
> not work for me (maybe that interface is only supposed to be implemented by
> actions)
That interface is meant for actions. The best way to get a ServletContext is
to do the following from an interceptor -
final ActionContext context = invocation.getInvocationContext();
ServletContext servletContext = (ServletContext)
context.get(org.apache.struts2.StrutsStaticsSERVLET_CONTEXT);
You may face a few issues though. I've thought briefly about EJB + Struts2
lately and I'll admit to a lack of experience with EJB, but it seems to me
that it would be somewhat difficult to combine the two easily. Many of the EJB
annotations can appear on private members (i.e. @PersistenceContext). In
Struts2, we create actions via our own ObjectFactory, which can be overridden
by a plugin.
There are at least two plugins available that provide EJB integration, but
they go about it by introducing a new annotation that are then checked for in
an interceptor with EJBs injected when the annotation is found ->
http://code.google.com/p/struts2ejb3/
http://code.google.com/p/struts2ejb3-jboss-plugin/
I'm not particularly familiar with OpenEJB, but I'd like to help however I
can. So, let me know if you need the help.
-Wes
--
Wes Wannemacher
Author - Struts 2 In Practice
Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
http://www.manning.com/wannemacher
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