Seam SPI
pmuir Jul 17, 2008 10:51 AM[Posting here as Seam uses mailing lists for development discussions and the Seam users forum isn't hosted on jboss.org, please move if it is the incorrect place]
Why isn't this in the forums?
Because I was asking Stan's opinion on something before taking it to a wider audience.
Pete, your solution is a joke.
Why does an integration api require you
to replace classes?
Because I don't think want users to have to deploy jboss-seam.jar and jboss-seam-spi.jar to their app server of choice.
1) Define the spi in jboss-seam.jar
They should be interfaces (the i in spi)
Exactly. This is what I want to do.
2) Provide a default implementation in jboss-seam.jar
(if necessary) with a mechanism to override the
implementation class for each integration point,
e.g. system properties or service provider mechanism
Yes, currently we provide two options for specifying extensions, firstly via system properties, secondly via a .properties file in META-INF/ for scenarios like this.
3) We can implementation those interfaces in a different
way for jboss-x.y.z or somebody else can do it
for another-environment-1.2.3
Yes.
However AFAIK JBoss isolated classloading won't allow this simple a solution.
jboss-seam.jar is deployed in ${project}.ear/lib/jboss-seam.jar, with isolated classloading turned on. Therefore /default/deploy/lib/jboss-seam-jbas5.jar wouldn't be able to load the interfaces defined in jboss-seam.jar deployed inside the ear.
And a quick test shows this to be the case. I added the interface Foo to jboss-seam.jar, added a jar /default/deploy/lib/jboss-seam-jbas5.jar with the class FooImpl implements Foo, and then tried to instantiate FooImpl using Foo foo = (Foo) Class.forName("org.jboss.seam.as5.FooImpl").newInstance(); when Seam deploys. As expected, I get a NCDFE.
org.jboss.seam.InstantiationException: Could not instantiate Seam component: fooTest at org.jboss.seam.Component.newInstance(Component.java:2103) at org.jboss.seam.contexts.Contexts.startup(Contexts.java:304) at org.jboss.seam.contexts.Contexts.startup(Contexts.java:278) at org.jboss.seam.contexts.ServletLifecycle.endInitialization(ServletLifecycle.java:95) at org.jboss.seam.init.Initialization.init(Initialization.java:630) at org.jboss.seam.servlet.SeamListener.contextInitialized(SeamListener.java:34) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3856) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4361) at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:790) at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:770) at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:553) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:296) at org.jboss.mx.server.RawDynamicInvoker.invoke(RawDynamicInvoker.java:164) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.apache.catalina.core.StandardContext.init(StandardContext.java:5312) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:296) at org.jboss.mx.server.RawDynamicInvoker.invoke(RawDynamicInvoker.java:164) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.web.tomcat.service.TomcatDeployer.performDeployInternal(TomcatDeployer.java:301) at org.jboss.web.tomcat.service.TomcatDeployer.performDeploy(TomcatDeployer.java:104) at org.jboss.web.AbstractWebDeployer.start(AbstractWebDeployer.java:375) at org.jboss.web.WebModule.startModule(WebModule.java:83) at org.jboss.web.WebModule.startService(WebModule.java:61) at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289) at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245) at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978) at $Proxy0.start(Unknown Source) at org.jboss.system.ServiceController.start(ServiceController.java:417) at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy44.start(Unknown Source) at org.jboss.web.AbstractWebContainer.start(AbstractWebContainer.java:466) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142) at org.jboss.mx.interceptor.DynamicInterceptor.invoke(DynamicInterceptor.java:97) at org.jboss.system.InterceptorServiceMBeanSupport.invokeNext(InterceptorServiceMBeanSupport.java:238) at org.jboss.wsf.container.jboss42.DeployerInterceptor.start(DeployerInterceptor.java:87) at org.jboss.deployment.SubDeployerInterceptorSupport$XMBeanInterceptor.start(SubDeployerInterceptorSupport.java:188) at org.jboss.deployment.SubDeployerInterceptor.invoke(SubDeployerInterceptor.java:95) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy45.start(Unknown Source) at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025) at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1015) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782) at sun.reflect.GeneratedMethodAccessor20.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy9.deploy(Unknown Source) at org.jboss.deployment.scanner.URLDeploymentScanner.deploy(URLDeploymentScanner.java:421) at org.jboss.deployment.scanner.URLDeploymentScanner.scan(URLDeploymentScanner.java:634) at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.doScan(AbstractDeploymentScanner.java:263) at org.jboss.deployment.scanner.AbstractDeploymentScanner.startService(AbstractDeploymentScanner.java:336) at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289) at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245) at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978) at $Proxy0.start(Unknown Source) at org.jboss.system.ServiceController.start(ServiceController.java:417) at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy4.start(Unknown Source) at org.jboss.deployment.SARDeployer.start(SARDeployer.java:302) at org.jboss.deployment.MainDeployer.start(MainDeployer.java:1025) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:819) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:782) at org.jboss.deployment.MainDeployer.deploy(MainDeployer.java:766) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.interceptor.AbstractInterceptor.invoke(AbstractInterceptor.java:133) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.interceptor.ModelMBeanOperationInterceptor.invoke(ModelMBeanOperationInterceptor.java:142) at org.jboss.mx.server.Invocation.invoke(Invocation.java:88) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.mx.util.MBeanProxyExt.invoke(MBeanProxyExt.java:210) at $Proxy5.deploy(Unknown Source) at org.jboss.system.server.ServerImpl.doStart(ServerImpl.java:482) at org.jboss.system.server.ServerImpl.start(ServerImpl.java:362) at org.jboss.Main.boot(Main.java:200) at org.jboss.Main$1.run(Main.java:508) at java.lang.Thread.run(Thread.java:613) Caused by: java.lang.RuntimeException: exception invoking: create at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:136) at org.jboss.seam.Component.callComponentMethod(Component.java:2208) at org.jboss.seam.Component.callCreateMethod(Component.java:2131) at org.jboss.seam.Component.newInstance(Component.java:2091) ... 141 more Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.seam.util.Reflections.invoke(Reflections.java:22) at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:31) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56) at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:31) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:42) at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68) at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107) at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:166) at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:102) at org.jboss.seam.FooTest_$$_javassist_0.create(FooTest_$$_javassist_0.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.jboss.seam.util.Reflections.invoke(Reflections.java:22) at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:126) ... 144 more Caused by: java.lang.NoClassDefFoundError: org/jboss/seam/Foo at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:675) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124) at java.net.URLClassLoader.defineClass(URLClassLoader.java:260) at java.net.URLClassLoader.access$100(URLClassLoader.java:56) at java.net.URLClassLoader$1.run(URLClassLoader.java:195) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at org.jboss.mx.loading.RepositoryClassLoader.findClassLocally(RepositoryClassLoader.java:682) at org.jboss.mx.loading.RepositoryClassLoader.findClass(RepositoryClassLoader.java:662) at java.lang.ClassLoader.loadClass(ClassLoader.java:316) at org.jboss.mx.loading.RepositoryClassLoader.loadClassLocally(RepositoryClassLoader.java:200) at org.jboss.mx.loading.ClassLoadingTask$ThreadTask.run(ClassLoadingTask.java:131) at org.jboss.mx.loading.LoadMgr3.nextTask(LoadMgr3.java:399) at org.jboss.mx.loading.RepositoryClassLoader.loadClassImpl(RepositoryClassLoader.java:527) at org.jboss.mx.loading.RepositoryClassLoader.loadClass(RepositoryClassLoader.java:415) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:374) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:164) at org.jboss.seam.FooTest.create(FooTest.java:17) ... 165 more
Any suggestions
>> On Thu, 2008-07-17 at 09:25 -0400, Stan Silvert wrote:
>> I assume you mean /default/lib/jboss-seam-spi.jar and not
>> /default/deploy/lib/jboss-seam-spi.jar.
Yes.
>> I'm not sure if it's a good idea to rely on classloading order if you
> can avoid it. That always led to support issues in 3.x and 4.x.
>> Adrian would know the best solution for JBoss 5. I would say that there
>> are probably some cool new features for this, but Adrian doesn't do cool.
> Stan
>Pete Muir wrote:
>>All this stuff to make Seam work on JBoss 5 (needing to call JBoss
>>specific methods) makes me think we need an SPI for Seam, so that the
>>relevant code can live in JBoss 5, not Seam.
>>
>>However, I don't want to end up having to deploy jboss-seam.jar and
>>jboss-seam-spi.jar in other app servers, so jboss-seam.jar will need to
>>include the jboss-seam-spi.jar classes. So, we need to make sure the
>>JBoss classloader always loads the classes from
>>/default/deploy/lib/jboss-seam-spi.jar before the ones from
>>jboss-seam.jar. IIRC this should work. Do you know?
>>Best,