Re: [OS-webwork] [OS-xwork] Spring IoC integration

[Cameron Braid]

It is a neater soloution to provide a plugable external resolver system into xwork. Xwork's IOC container is currently limited to only one instance of any component type, similiar to Nano or Pico container's 'metadata free' configuiration. (i.e. it uses type matching to resolve components) The external resolver system allows :     component frameworks (pico,nano,spring etc..) to provide an implementation of the ExternalRefrenceRersolver interface.     multiple component frameworks (or multiple instances of a multiple component frameworks) to co-exist within a single webwork (or xwork) app by parameterizing the resolvers. Using an interceptor to achieve this became messy since the mapping from action properties to component names needed to be specified as a string in an interceptor param, per action. Cameron Francois Beauregard wrote: Why all of this external reference resolver thing gets into XWork? Couldn't you just extend DefaultActionProxyFactory, DefaultActionInvocation and do whatever logic to integrate with the IoC container and/or use an interceptor? Even XWorks own IoC container does not need this kind of modification to XWork.xml, it looks like it only needs an interceptor and stores its configuration in an xml file. You can also have a look at PicoContainer's integration (in NanoContainer), it is neatly done. Cheers, ___________________________ François Beauregard, b.ing. Vice-président Recherche et développement Pyxis Technologies www.pyxis-tech.com T : (450) 681-9094, poste 102 F : (450) 681-5758 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Cameron Braid Sent: December 12, 2003 1:32 AM To: [EMAIL PROTECTED] Subject: Re: [OS-webwork] [OS-xwork] Spring IoC integration It looks like noone else is interested in discussing this. I have refactored xwork so that the external refrence resolvers are defined as described below <xwork> <package name='test' extends='webwork-default'> <external-resolvers> <external-resolver name="test" class="com.opensymphony.xwork.config.TestExternalReferenceResolver"> <param name='stringParam'>stringParamValue</param> </external-resolver> <external-resolver name="test2" class="com.opensymphony.xwork.config.Test2ExternalReferenceResolver"/> </external-resolvers> <default-external-resolver-ref name='test'/> <action name="TestExternalRefResolver3" class="com.opensymphony.xwork.ExternalReferenceAction"> <external-ref required="true" name="Boo">myBoo</external-ref> <interceptor-ref name="debugStack"/> <interceptor-ref name="defaultStack"/> </action> <!-- test where external-resolver-ref overrides the package's resolver --> <action name="TestExternalRefResolver5" class="com.opensymphony.xwork.ExternalReferenceAction"> <external-ref name="foo" external-resolver-ref='test2'>myFoo</external-ref> <interceptor-ref name="debugStack"/> <interceptor-ref name="defaultStack"/> </action> </package> </xwork> I have updated the test cases to use this new structure, and added tests for the new features. This has required that the ExternalReferenceResolver interface be changed a little bit, simplifying the implementation. Previousally ExternalReferenceResolver.resolveReferences(..) had to resolve all external refrences for an action, where as now it just resolves a single refrence at a time. public interface ExternalReferenceResolver { public void resolveReferences(ActionInvocation invocation, ExternalReference reference) throws ReferenceResolverException; } This simplifies the implemetation of the resolver because it doesn't need to know about the ActionConfig at all, since ExternalReference contains the action property name, the external ref string and the required boolean. It is the responsiblity of the ExternalReferencesInterceptor to call the relevant resolver for each <external-ref> tag for the action. I can add a Jira task, and attach the patch if anyone is interested. I would prefer that this code gets added before the final release. Cameron. Cameron Braid wrote: Ross Mason wrote: Cameron Braid wrote: Ross Mason wrote: Cameron Braid wrote: I have downloaded and integrated this code though and the tests run perfectly (after creating my my own ServletContextAware interface and removing refrences to the confluence packages) I really like the work that you have done. Though I think some more work is required to be able to integrate into xwork/webwork Cool! I can't see how the servlet context is set onto the SpringServletContextReferenceResolver or the ApplicationContext is set onto the SpringApplicationContextReferenceResolver (depending on the one that is used) you construct the ExternalReferenceResolver using this code, and immediately add it to the package config. Class erResolverClazz = ClassLoaderUtil.loadClass(externalReferenceResolver, ExternalReferenceResolver.class); erResolver = (ExternalReferenceResolver) erResolverClazz.newInstance(); I guess that the ServletContextAware interface could be added to webwork, though the question remains - how is the ServletContextAware.setServletContext(..) method going to get called ? We could use a ServletContextListener to set the contexts on our resolvers... Could we access the packageConfig from a listener? Yeah I guess we could, though this starts to get ugly when each different resolver needs its own listener that is bound to the action config api. You only need one listener to set the Servlet context on all Resolvers that are ServletContextAware. I'll attach the one I'm using to the issue. Sounds like we need to get the DefaultComponentManager to bootstrap the external refrence resolvers ;) Actually... my point here was that each type of resolver... ie the spring one, the XXXFramework one and any other framework integration one will require someone to code a specific ConfigurerListener to set any external resources that the resolver requires. I think that if this can be done with simple parameter based configuration then it will be a lot simpler. I propost the following soloution : 1 : have different SpringXXXReferenceResolver classes in xwork and webwork like this : xwork : Spring/ClassPathXmlApplicationContext/ReferenceResolver or a Spring/FileSystemXmlApplicationContext/ReferenceResolver webwork : Spring/WebApplicationContext/ReferenceResolver - using WebApplicationContextUtils.getWebApplicationContext(ServletActionContext.get ServletContext()) to obtain the application context I agree, we should have different implementations, separated like this. In my test case I have provided a Spring/XmlFileApplicationContext, so we could just refactor that out. Certainly can. This works find for webwork based apps, though for xwork based apps that the SpringClassPathXmlApplicationContextReferenceResolver and SpringFileSystemXmlApplicationContextReferenceResolver require configuration to specify the filename.. therfore step two is required : 2 : allow for external refrence resolvers to be declards by name, class and to be parameterizable like interceptors. the refer to the by name instead of className e.g. : <xwork> <package ... externalReferenceResolver="spring"> .... <!-- NEW FEATURE : new node set --> <externalRefrenceResolvers> <externalRefrenceResolver name='spring' class="SpringWebApplicationContextReferenceResolver"/> <externalRefrenceResolver name='springXmlFile' class="SpringClassPathXmlApplicationContextReferenceResolver"> <param name="filename">myApplicationContext.xml</param> </externalRefrenceResolver > </externalRefrenceResolvers> .... <action name='...' class='...'> <!-- NEW FEATURE : externalRefrenceResolver attribute --> <external-ref externalRefrenceResolver='springXmlFile' name='foo'>myFoo</external-ref> <external-ref name='bar'>myBar</external-ref> </action> </package> </xwork> this allows for reusing the same configured resolver in multiple packages - which you can do now, though without configuration. this allows for each external-ref tag to optionally use a different resolver as in the example above Ok that looks like it would work, I think we should declare resolvers the way you suggested. Though I don't think we need then externalReferenceResolver attrib on the external-ref element. We can just assume all actions in a package use the same Resolver. I think it's neater that way; You can still use different Containers on different packages to resolve your references and there would be a more logical grouping of package/container. I agree that is is not necessary to allow the resolver to be overriden per external-ref though I think it could be a usefull feature to have. Say you are using a thirs party spring based component package - say for security - and you want each action's securityManager property to be resolved from this context instead of the package's one. I guess that another way of specifying it would be to use <external-ref name='foo'>springXmlFile:myFoo</external-ref> and to modify the interceptor to look for the : char. just my 2c worth ;) See your point, I guess we need to throw the notation up for discussion. I don't really mind the syntax for specifying which resolver to use. SO there are two questions 1. Do we need to be able to override the resolver on a per refrence basis 2. If we can override, what is the syntax ? Does anyone else have any thoughs or suggestions ? I am sure that other frameworks will require some sort of runtime configuration for the external reference resolvers as well. Any comments ? yep! Cameron Cheers, ross Thanks Cameron Ross Mason wrote: Cheers mate. I've just attached the SpringExternalReferenceResolver implmentation and tests to the Jira Issue. http://jira.opensymphony.com/secure/ViewIssue.jspa?key=XW-122 Ross Patrick Lightbody wrote: This is good stuff -- not sure about a 1.0 release though. We'll try to get a point release out shortly after though to support this. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Ross Mason Sent: Monday, November 17, 2003 8:02 PM To: [EMAIL PROTECTED] Subject: Re: [OS-webwork] [OS-xwork] Spring IoC integration I'll fix the commons dependancies first :-) Ross Mason wrote: I've tried running the patch again (through Eclipse) and I get the same problem - It only creates patch entries for new files? I know this isn't a subject for this list, but does anyone know why this happens? Anyway Cameron, I'll create a zip of the changes for now and attach it to the the issue and this list. Cheers, Ross Cameron Braid wrote: The patch seems to be missing code in the configuration classes... since I have applied it, I am geting compilation errors : not defined : invocation.getProxy().getConfig().getPackageName() invocation.getProxy().getConfig().getExternalRefs(); packageConfig.getExternalRefResolver() Thanks, Cameron Ross Mason wrote: Hi, As per the discussion late last week, we have a patch for Xwork so that it can use an external container to resolve component references. I've created the following issue - http://jira.opensymphony.com/secure/ViewIssue.jspa?key=XW-122 I've added a breakdown of the changes below, in summary, this is how it works- You can configure a action to have external references in the xwork.xml using a new <external-ref> tag on the action When the action is configured the external refs are stored on the action config. When the action is invoked, there is a new interceptor that will resolve these references. It does this by using a new attribute on the package config called externalReferenceResolver i.e. <package name="default" externalReferenceResolver="com.atlassian.xwork.ext.SpringServletContextR eferenceResolver"> In this case, the SpringServletContextReferenceResolver implementation will handle the work of looking up and setting the references on the action. Note, if a resolver is not found on the actions package, it will tranverse up the package heirarchy to find one. We have an implementation for Spring, but I have not included it in this patch as it should probably go into an xwork-ext sub-project. Let me know what you want me to do with this... Here are the changes and additions to the xwork codebase - 1. added 2 new config attributes - - a new element external-ref to the action element in the config. i.e <external-ref name="foo">Foo</external-ref> where name is the setter method name and Foo is the reference to lookup. - added an attribute to the package element called externalReferenceResolver which supplies a FQ classname to an ExternalReferenceResolver implementation. 2. Updated the xwork DTD accordingly. 3. Added 4 new classes - - External Reference - an encapsulation of the external-ref tag - ExternalReferenceResolver - an interface to provide implementations for resolving references from an external container - ExternalReferencesInterceptor - will resolve references on a given ActionInvocation - ReferenceResolverException - thrown by ExternalReferenceResolver 4. Added support for external references to the ActionConfig. I also added the attribute packageName to the ActionConfig, so that the Interceptor could determine which package the action belonged to in order to find the externalReferenceResolver. 5. Added support for the externalReferenceResolver attribute to the PackageConfig. 6. Added support for the extra configuration to the XMLConfigurationProvider and DefaultConfigurationProvider 7. Added tests in the org.opensymphony.xwork.config.ExternalReferenceResolverTest I've attached a cvs patch with all the changes. I built the patch against the latest src. Cheers, Ross ------------------------------------------------------- This SF. Net email is sponsored by: GoToMyPC GoToMyPC is the fast, easy and secure way to access your computer from any Web browser or wireless device. 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