Just a wild guess, but it sounds like an 'order of things' type problem,
Tapestry being a filter and not essentially a servlet, the context might not be
available at that point.
----- Original Message -----
From: "Ulrich Stärk" <[EMAIL PROTECTED]>
To: "Tapestry users" <users@tapestry.apache.org>
Sent: Monday, 22 September, 2008 4:51:23 PM GMT +02:00 Athens, Beirut,
Bucharest, Istanbul
Subject: NPE when trying to contribute ServletContextSymbolProvider to
SymbolSource (WAS: Re: Page pool hard limit and page instance usage)
The problem seems to be, that the ServletContext provided by
ApplicationGlobals is null when Tapestry tries to contribute the
ServletContextSymbolProvider to the SymbolSource service. I don't know why
this is the case. Maybe someone else can shed some light on this.
Uli
Am Mo, 22.09.2008, 08:08, schrieb 9902468:
>
> Hi again,
>
> I'm hitting my head to wall here with ServletContextSymbolProvider. It is
> configured like this:
>
> public static void
> contributeSymbolSource(OrderedConfiguration<SymbolProvider> configuration,
> @InjectService("ServletContextSymbolProvider") SymbolProvider
> servletContextSymbolProvider)
> {
> configuration.add("ServletContextSymbolProvider" ,
> servletContextSymbolProvider, "after:SystemProperties",
> "before:ApplicationDefaults");
> }
>
> public static ServletContextSymbolProvider
> buildServletContextSymbolProvider(ApplicationGlobals globals){
> return new
> ServletContextSymbolProvider(globals.getServletContext());
> }
>
> And it always ends to this error:
> java.lang.RuntimeException: Unable to instantiate class
> org.apache.tapestry5.services.TapestryModule as a module builder:
> Exception
> constructing service 'Alias': Error invoking service builder method
> org.apache.tapestry5.services.TapestryModule.buildAlias(Logger, String,
> AliasManager, Collection) (at TapestryModule.java:217) (for service
> 'Alias'): Exception constructing service 'SymbolSource': Error invoking
> constructor
> org.apache.tapestry5.ioc.internal.services.SymbolSourceImpl(List) (at
> SymbolSourceImpl.java:198) via
> org.apache.tapestry5.ioc.services.TapestryIOCModule.bind(ServiceBinder)
> (at
> TapestryIOCModule.java:38) (for service 'SymbolSource'): Error invoking
> service contribution method
> com.example.tapestry5.services.ExampleModule.contributeSymbolSource(OrderedConfiguration,
> SymbolProvider): Error building service proxy for service
> 'ServletContextSymbolProvider' (at
> com.example.tapestry5.services.ExampleModule.buildServletContextSymbolProvider(ApplicationGlobals)
> (at ExampleModule.java:215)): Error invoking service builder method
> com.example.tapestry5.services.ExampleModule.buildServletContextSymbolProvider(ApplicationGlobals)
> (at ExampleModule.java:215) (for service 'ServletContextSymbolProvider'):
> Exception constructing service 'Alias': Construction of service 'Alias'
> has
> failed due to recursion: the service depends on itself in some way. Please
> check org.apache.tapestry5.services.TapestryModule.buildAlias(Logger,
> String, AliasManager, Collection) (at TapestryModule.java:217) for
> references to another service that is itself dependent on service 'Alias'.
>
> I can't determine where the recursion is. Is the ApplicationGlobals
> initiating the construction of Alias service? If this is true then
> ApplicationGlobsals cannot be used while I'm constructing my alias
> overrides?
>
> Is there anyone out there who has this working?
>
> - 99
>
>
> Ulrich Stärk wrote:
>>
>> You don't have to write your own ServletContextSymbolProvider, it
>> already
>> comes shipped with
>> Tapestry. See here
>> http://tapestry.apache.org/tapestry5/apidocs/index.html?org/apache/tapestry5/ioc/services/SymbolProvider.html
>> You just have to configure it.
>>
>> Uli
>>
>> 9902468 schrieb:
>>> Yep, just read through your discussion:
>>>
>>> http://www.nabble.com/forum/ViewPost.jtp?post=19547763&framed=y&skin=302
>>>
>>> and that would be the intelligent way of doing it :)
>>>
>>> I'll code symbol provider when I have time. Hopefully these providers
>>> can
>>> be
>>> included in T5 distribution, as these are highly reusable and add only
>>> little to none "weight" to the distribution.
>>>
>>> - 99
>>>
>>>
>>> Ulrich Stärk wrote:
>>>> Why not instantiate a ServletContextSymbolProvider (the ServletContext
>>>> is
>>>> available from the
>>>> ApplicationGlobals service) and contribute it to the SymbolProvider
>>>> before
>>>> ApplicationDefaults and
>>>> FactoryDefaults. That way you can directly override
>>>> tapestry.page-pool.hard-limit and automatically
>>>> have all other init parameters as symbols, too.
>>>>
>>>> Uli
>>>>
>>>> 9902468 schrieb:
>>>>> I always keep nabble open when I'm at work :)
>>>>>
>>>>> These parameters can be transferred to web.xml, so that recompile is
>>>>> not
>>>>> needed when changing these parameters:
>>>>>
>>>>> public static void
>>>>> contributeApplicationDefaults(MappedConfiguration<String,
>>>>> String> configuration, ApplicationGlobals globals) {
>>>>>
>>>>> configuration.add("tapestry.page-pool.hard-limit",
>>>>> globals.getServletContext().getInitParameter("page_hard_limit"));
>>>>>
>>>>> }
>>>>>
>>>>> and in web.xml
>>>>>
>>>>> <web-app>
>>>>> <display-name>Some Tapestry 5 Application</display-name>
>>>>> <context-param>
>>>>> <!-- The only significant configuration for Tapestry 5, this
>>>>> informs
>>>>> Tapestry of where to look for pages, components and mixins. -->
>>>>> <param-name>tapestry.app-package</param-name>
>>>>> <param-value>fi.hanken.resbuilder.tapestry5</param-value>
>>>>> </context-param>
>>>>> <context-param>
>>>>> <param-name>page_hard_limit</param-name>
>>>>> <param-value>60</param-value>
>>>>> </context-param>
>>>>>
>>>>> This can be used through out every single service and page and
>>>>> component.
>>>>> To
>>>>> access this in a page or component use:
>>>>>
>>>>> @Property @Inject @Value("${page_hard_limit}")
>>>>> private String pageHardLimit;
>>>>>
>>>>> Injection can be used in service constructor also (I think) or by
>>>>> using
>>>>> buildSomeService method instead of the usual binder.bind
>>>>>
>>>>> Of course T5 makes it easy to read these from a file or database or
>>>>> from
>>>>> what not, but I have noticed that many admins accept editing web.xml
>>>>> and
>>>>> restarting the app ok.
>>>>>
>>>>> Hopefully this helps. (And makes it easier to say to admins that just
>>>>> configure the app according to the load they are experiencing.)
>>>>>
>>>>> -99
>>>>>
>>>>>
>>>>> nille hammer wrote:
>>>>>> Man that was a quick answer! Thanks for that. I am aware of this
>>>>>> options
>>>>>> in the configuration. I had not tuned them before, because load is
>>>>>> not
>>>>>> my problem. Anyway I have tuned them now and am currently waiting
>>>>>> for
>>>>>> the admistrator to deploy the newest war.
>>>>>>
>>>>>> According to acces-logs I was the only user accessing the page. So
>>>>>> as
>>>>>> far as I understand the mechanism only one instance of index should
>>>>>> have
>>>>>> been created and not 20. I think it is an issue with configuration
>>>>>> in
>>>>>> production environment. But I have no idea where to take a closer
>>>>>> look
>>>>>> (i.e. where to build in log-messages, which of Tomcat's
>>>>>> configuration
>>>>>> options to check etc.).
>>>>>>
>>>>>> So suggestions are still more than welcome.
>>>>>>
>>>>>> Nillehammer
>>>>>>
>>>>>> 9902468 schrieb:
>>>>>>> Hi,
>>>>>>>
>>>>>>> Eventually we had to add these to appmodule:
>>>>>>>
>>>>>>> configuration.add("tapestry.page-pool.hard-limit", "60");
>>>>>>> configuration.add("tapestry.page-pool.soft-limit", "20");
>>>>>>> configuration.add("tapestry.page-pool.soft-wait", "20 ms");
>>>>>>>
>>>>>>> as instructed here:
>>>>>>> http://tapestry.apache.org/tapestry5/guide/conf.html
>>>>>>>
>>>>>>> This solved our problems, and you can go up as long as your server
>>>>>>> has
>>>>>>> memory. Our problems were only in production, as development stress
>>>>>>> just
>>>>>>> isn't enough. (This is why one really should do load testing with
>>>>>>> jmeter
>>>>>>> or
>>>>>>> similar tool.)
>>>>>>>
>>>>>>> The defaults could be a bit more? Or considerably less, so that the
>>>>>>> developer would hit these walls during development and understands
>>>>>>> to
>>>>>>> load
>>>>>>> test / tune the parameters.
>>>>>>>
>>>>>>> - 99
>>>>>>>
>>>>>>>
>>>>>>> nille hammer wrote:
>>>>>>>> Hi list,
>>>>>>>>
>>>>>>>> I am also facing the problem that 9902468 had. I have -according
>>>>>>>> to
>>>>>>>> Howard's suggestion- replaced every pageLink with a customPageLink
>>>>>>>> to
>>>>>>>> prevent targeted pages from being created unecessarily. The
>>>>>>>> problem
>>>>>>>> persists. Trying to load the index-Page of my application with a
>>>>>>>> browser
>>>>>>>> I have to wait about two minutes before I get an empty page. In
>>>>>>>> the
>>>>>>>> app's log the following Exception appears:
>>>>>>>>
>>>>>>>> java.lang.RuntimeException: The page pool for page 'Index' (in
>>>>>>>> locale
>>>>>>>> de) has been exausted: there are 20 instances currently being used
>>>>>>>> and
>>>>>>>> no more can be created. Try increasing the hard limit (symbol
>>>>>>>> tapestry.page-pool.hard-limit) to allow additional instances to be
>>>>>>>> created, or increasing the soft wait (symbol
>>>>>>>> tapestry.page-pool.soft-wait) to trade away some throughput for
>>>>>>>> more
>>>>>>>> efficient use of page instances.
>>>>>>>> at
>>>>>>>> org.apache.tapestry5.internal.services.PagePoolCache.checkout(PagePoolCache.java:199)
>>>>>>>> at
>>>>>>>> org.apache.tapestry5.internal.services.PagePoolImpl.checkout(PagePoolImpl.java:107)
>>>>>>>> at
>>>>>>>> $PagePool_11c76f8cf9a.checkout($PagePool_11c76f8cf9a.java)
>>>>>>>> at
>>>>>>>> org.apache.tapestry5.internal.services.RequestPageCacheImpl.get(RequestPageCacheImpl.java:43)
>>>>>>>> at
>>>>>>>> $RequestPageCache_11c76f8cf99.get($RequestPageCache_11c76f8cf99.java)
>>>>>>>> at
>>>>>>>> $RequestPageCache_11c76f8cf91.get($RequestPageCache_11c76f8cf91.java)
>>>>>>>> ...
>>>>>>>>
>>>>>>>> In development and in production environment I use Java 6 and
>>>>>>>> Tomcat
>>>>>>>> 6.
>>>>>>>> Tapestry is 5.0.14. The strange thing is that I am only seeing
>>>>>>>> this
>>>>>>>> in
>>>>>>>> production environment.
>>>>>>>>
>>>>>>>> Has anyone a suggestion how to track this down? I am pretty stuck
>>>>>>>> with
>>>>>>>> this.
>>>>>>>>
>>>>>>>> Thanks in advance, nillehammer
>>>>>>>>
>>>>>>>> Howard Lewis Ship wrote
>>>>>>>>> Tapestry is obtaining page instances to see if there is an
>>>>>>>>> activation
>>>>>>>>> context for the page.
>>>>>>>>>
>>>>>>>>> I expect to optimize this in the future, to check to see if the
>>>>>>>>> page
>>>>>>>>> has an event handler for the passivate event.
>>>>>>>>>
>>>>>>>>> In the meantime, you could build your own PageLink component that
>>>>>>>>> generates the link by invoking
>>>>>>>>> ComponentResources.createPageLink("pagename", true) ... that will
>>>>>>>>> tell
>>>>>>>>> Tapestry to generate a link to the page with no activation
>>>>>>>>> context,
>>>>>>>>> and the page will NOT be queried for its context, and therefore,
>>>>>>>>> won't
>>>>>>>>> need to be attached to the current request.
>>>>>>>>>
>>>>>>>>> On Fri, Aug 29, 2008 at 3:58 AM, 9902468
>>>>>>>>> <[EMAIL PROTECTED]>
>>>>>>>>> wrote:
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>> we are experiencing strange hard pool limit reached exceptions.
>>>>>>>>>> (For
>>>>>>>>>> the
>>>>>>>>>> user count that we have.) After debugging a little, it seems
>>>>>>>>>> that
>>>>>>>>>> our
>>>>>>>>>> left
>>>>>>>>>> menu component, which is full of page links, instantiates not
>>>>>>>>>> only
>>>>>>>>>> the
>>>>>>>>>> page
>>>>>>>>>> that we are at, but also the ones that are referenced in page
>>>>>>>>>> link.
>>>>>>>>>>
>>>>>>>>>> This can be seen also in that exception page is shown, if one of
>>>>>>>>>> the
>>>>>>>>>> pages
>>>>>>>>>> that are referenced in page links have an error.
>>>>>>>>>>
>>>>>>>>>> Is this correct behavior? And should we really use common a
>>>>>>>>>> href=
>>>>>>>>>> tags
>>>>>>>>>> to
>>>>>>>>>> avoid this? Further more, is it possible to create infinite
>>>>>>>>>> loop,
>>>>>>>>>> when
>>>>>>>>>> page
>>>>>>>>>> a has page link to page b, which has page link to page a?
>>>>>>>>>>
>>>>>>>>>> - 99
>>>>>>>>>> --
>>>>>>>>>> View this message in context:
>>>>>>>>>> http://www.nabble.com/Page-pool-hard-limit-and-page-instance-usage-tp19217773p19217773.html
>>>>>>>>>> Sent from the Tapestry - User mailing list archive at
>>>>>>>>>> Nabble.com.
>>>>>>>>>>
>>>>>>>>>>
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>>>>>>>>
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>>>>>>
>>>>>>
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>>>>
>>>>
>>>
>>
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>>
>
> --
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> http://www.nabble.com/Page-pool-hard-limit-and-page-instance-usage-tp19217773p19602371.html
> Sent from the Tapestry - User mailing list archive at Nabble.com.
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