FYI: http://tapestryjava.blogspot.com/2012/02/plastic-advanced-example.html
On Mon, Feb 27, 2012 at 8:45 AM, Howard Lewis Ship <hls...@gmail.com> wrote: > On Fri, Feb 24, 2012 at 9:14 AM, Blower, Andy > <andy.blo...@proquest.co.uk> wrote: >> Sorry, premature celebration. :-( >> >> It works until the proxy is serialized, which throws a >> NotSerializableException. In normal binding / override the proxy is a >> JustInTimeObjectCreator and using this proxy it seems to be a >> ReloadableObjectCreator, but nether of them are marked as Serializable so >> I'm not sure how it normally works. My understanding was that SSO's could >> hold references to services since these were simply referring to a proxy >> which essentially could be serialized and replicated across a cluster since >> it only sent a token. > > The code for this is hidden inside ModuleImpl.createProxyInstance() > which creates a proxy that implements Serializable, and the optional > writeReplace() method. See all ModuleImpl.createProxy(). > > Basically, the proxy uses writeReplace() to write a ServiceProxyToken > into the output stream; when the stream is deserialized, the > ServiceProxyToken uses a static field to locate the Registry, and > replaces itself with the service. > > If there is a way to @Inject a @Local service to contribute to > ServiceOverrides, that will work better, as the local service will > have it own proxy & ServiceProxyToken. Much like the second example > on http://tapestry.apache.org/ioc-cookbook-overriding-ioc-services.html > > But I'm not sure how this affects your original problem. > > You may find it is easier to use either method advice, or service > decoration, to augment the existing service in place, rather than > replace it entirely. > > In fact, this does point to the idea that Tapestry could use a new > type of module method for replacing built-in services with > replacements cleanly, rather than rely on ServiceOverrides. Such a > module method (and related RegistrtyImpl support) would make the > replacement hide behind the original service's id and > ServiceProxyToken. > > >> >> How far out am I here? >> >> >> -----Original Message----- >> From: Blower, Andy [mailto:andy.blo...@proquest.co.uk] >> Sent: 22 February 2012 17:35 >> To: Tapestry users >> Subject: RE: [T5.3] Contributing a Service Override using addInstance() >> >> Yes that works! I had no idea you could do such a thing as I'd not see it >> anywhere in the documentation. >> >> I don't know if an addProxy() method is worth adding, our requirements seem >> quite unusual. If it would be useful to other Tapestry users then maybe. >> >> Thanks for the reply Howard. >> >> -----Original Message----- >> From: Howard Lewis Ship [mailto:hls...@gmail.com] >> Sent: 21 February 2012 19:51 >> To: Tapestry users >> Subject: Re: [T5.3] Contributing a Service Override using addInstance() >> >> This might work: >> >> @Contribute(ServiceOverride.class) >> >> public static void >> setupApplicationServiceOverrides(MappedConfiguration<Class,Object> >> configuration, ObjectLocator locator) >> >> { >> SomeServiceType override = locator.proxy(SomeServiceType.class, >> SomeServiceTypeOverrideImpl.class); >> >> configuration.add(SomeServiceType.class, override); >> >> } >> >> >> This contributes a proxy for the override, rather than the override itself >> ... meaning that eventual construction of SomeServiceTypeOverrideImpl is >> deferred until needed, and that will be after the MasterObjectProvider and >> ServicesOverride are constructed. >> >> Give it a try and report back! >> >> Perhaps we need complement addInstance() methods with addProxy() methods on >> the Configuration/OrderedConfiguration/MappedConfiguration >> interfaces? >> >> >> On Tue, Feb 21, 2012 at 6:33 AM, Blower, Andy <andy.blo...@proquest.co.uk> >> wrote: >>> Thanks for the reply Steve. The two classes I mention are Tapestry IoC >>> classes, not my own. >>> >>> What you describe is how most of our overrides are implemented but this one >>> is conditional - we only need to override this service in a specific >>> environment and that's what causes the issue. If I define it like that if >>> the override is not applied then the IoC has two implementations bound (if >>> you don't bind it you can't have it injected into the override method) and >>> will throw errors whenever the service is injected without a specific ID. >>> There are 100's of places where we have plain injections and is not >>> practical to change them. >>> >>> >>> -----Original Message----- >>> From: Steve Eynon [mailto:steve.ey...@alienfactory.co.uk] >>> Sent: 21 February 2012 10:36 >>> To: Tapestry users >>> Subject: Re: [T5.3] Contributing a Service Override using >>> addInstance() >>> >>> Hi, I'm not really sure what's going on as the two classes you mention, >>> ValidatingMappedConfigurationWrapper & AbstractConfigurationImpl, don't >>> appear in your code snippet. >>> >>> If you define your overriding service as an Interface (say in the >>> bind() method) then T5 will create a proxy for it. >>> >>> public static void bind(ServiceBinder binder) { >>> binder.bind(ToOverrideInterface.class, >>> ToOverrideImpl.class).withId("anything so we don't conflict with the >>> existing ID"); } >>> >>> then you can inject that in the service override like this: >>> >>> public static void contributeServiceOverride(MappedConfiguration >>> config, @Local ToOverrideInterface override) { >>> config.add(ToOverrideInterface.class, override); } >>> >>> The @Local is important, otherwise T5 doesn't know which serivce to inject >>> (yours or the one you're trying to override). >>> >>> Steve. >>> >>> >>> On 20 February 2012 20:54, Blower, Andy <andy.blo...@proquest.co.uk> wrote: >>>> I managed to get this to work by tracking down all dependencies and >>>> finding that one was being used in the services' constructor. Once I moved >>>> the initialisation code into a lazy init method I stopped getting the >>>> exceptions. >>>> >>>> Unfortunately, I still have an issue because when using addInstance() >>>> Tapestry is not using a proxy for the overriding service implementation, >>>> instead I'm getting a concrete reference instead which I thought never >>>> happened with Tapestry IoC. This causes problems when used in objects that >>>> are serialized to the session because it tries to serialize the service >>>> implementation rather than just the service proxy. >>>> >>>> My override looks like this: >>>> >>>> @Contribute(ServiceOverride.class) >>>> public static void >>>> setupApplicationServiceOverrides(MappedConfiguration<Class<?>, >>>> Object> >>>> configuration) >>>> { >>>> configuration.addInstance(ProductConfig.class, >>>> DynamicMultiProductConfig.class); >>>> } >>>> >>>> Basically the contributionType in ValidatingMappedConfigurationWrapper >>>> (AbstractConfigurationImpl) is Object which isn't an interface so a proxy >>>> isn't created. How can I change the signature of my module service >>>> override method so that contributionType is an interface and I get a >>>> service proxy like every other service? >>>> >>>> Can anyone help me? >>>> >>>> >>>> -----Original Message----- >>>> From: Blower, Andy [mailto:andy.blo...@proquest.co.uk] >>>> Sent: 15 February 2012 14:51 >>>> To: users@tapestry.apache.org >>>> Subject: [T5.3] Contributing a Service Override using addInstance() >>>> >>>> I've read the section below about contributing a service override. This >>>> method is exactly what I need to resolve an issue I'm having getting a >>>> conditional override implemented, but it doesn't appear to work if the >>>> service implementations' constructor has any other T5 service dependencies >>>> in the signature. (T5 complains that ServiceOverride depends on itself. >>>> >>>> Is this true, because that doesn't seem to be what's implied below by >>>> "handle dependency resolution", and makes addInstance of limited >>>> usefulness. I'm hoping I'm just missing something here. >>>> >>>> >>>> >>>> From http://tapestry.apache.org/ioc-cookbook-overriding-ioc-services.html : >>>> >>>> "In this case, it is very easy to supply your own alternate implementation >>>> of a service. >>>> AppModule.java (partial) >>>> >>>> @Contribute(ServiceOverride.class) >>>> >>>> public static void >>>> setupApplicationServiceOverrides(MappedConfiguration<Class,Object> >>>> configuration) >>>> >>>> { >>>> >>>> configuration.addInstance(SomeServiceType.class, >>>> SomeServiceTypeOverrideImpl.class); >>>> >>>> } >>>> >>>> The name of the method is not important, as long as the >>>> @Contribute<http://tapestry.apache.org/current/apidocs/org/apache/tapestry5/ioc/annotations/Contribute.html> >>>> annotation is present on the method. >>>> >>>> In this example, we are using addInstance() which will instantiate the >>>> indicated class and handle dependency resolution. (Be careful with this, >>>> because in some cases, resolving dependencies of the override class can >>>> require checking against the ServiceOverrides service, and you'll get a >>>> runtime exception about ServiceOverrides requiring itself!)" >>>> >>>> >>>> >>>> --------------------------------------------------------------------- >>>> To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org >>>> For additional commands, e-mail: users-h...@tapestry.apache.org >>>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org >>> For additional commands, e-mail: users-h...@tapestry.apache.org >>> >>> >>> >>> >>> --------------------------------------------------------------------- >>> To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org >>> For additional commands, e-mail: users-h...@tapestry.apache.org >>> >> >> >> >> -- >> Howard M. Lewis Ship >> >> Creator of Apache Tapestry >> >> The source for Tapestry training, mentoring and support. Contact me to learn >> how I can get you up and productive in Tapestry fast! >> >> (971) 678-5210 >> http://howardlewisship.com >> >> --------------------------------------------------------------------- -- Howard M. Lewis Ship Creator of Apache Tapestry The source for Tapestry training, mentoring and support. Contact me to learn how I can get you up and productive in Tapestry fast! (971) 678-5210 http://howardlewisship.com --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org For additional commands, e-mail: users-h...@tapestry.apache.org
