[jbossseam-issues] [JBoss JIRA] Commented: (JBSEAM-1583) seam:component intercept uses Seam standard rules by default

Michael Youngstrom (JIRA) jira-events at lists.jboss.org
Mon Jul 2 11:25:00 EDT 2007 

    [ http://jira.jboss.com/jira/browse/JBSEAM-1583?page=comments#action_12367474 ] 
            
Michael Youngstrom commented on JBSEAM-1583:
--------------------------------------------

seam:component will use a spring instantiated bean as a Seam bean and wraps this spring bean instance with the standard seam interceptors (if intercept==true).  Seam uses a proxy to achieve it's interceptor functionality.  Seam components require a no-arg constructor.

Looking at the Seam 2.0. code it appears some stuff has changed recently with regard to how interception is done.  Let me know if this functionality will work for you:

* <seam:component intercept="false"/> will make the spring bean a seam component inject static variables such as @Logger and not try to create a seam proxy (no need for no-arg constructor).

* <seam:component intercept="true"/> will make the spring bean a seam component and create a seam proxy.  @Logger will work but the spring bean will require a no-arg constructor.

* <seam:component/> will use Seam's method of determining if interception is needed or not (no interception if it is an entity bean or has the @BypassInterceptors on the class).

Will that work for you and remove the need for JBSEAM-1584?

> seam:component intercept uses Seam standard rules by default
> ------------------------------------------------------------
>
>                 Key: JBSEAM-1583
>                 URL: http://jira.jboss.com/jira/browse/JBSEAM-1583
>             Project: JBoss Seam
>          Issue Type: Bug
>          Components: Spring
>    Affects Versions: 2.0.0.BETA1
>            Reporter: Magnus Heino
>         Assigned To: Michael Youngstrom
>
> From spring-seam-2.0.xsd, intercept:
> Determines whether Seam interceptors should be wrapped around a bean, by overriding Seam's default rules. 
> Seldom do you want the seam interceptors wrapped around a sprig singleton.  Auto will use choose no
> interception for a singleton and use Seam standard rules otherwise.
> Looking at the code, I can't find anything about this "no interception for a singleton" default. 
> This bean
> <bean id="processRepository" class="se.lantmateriet.wfl.dataaccess.WsProcessRepository">
>     	<constructor-arg value="http://localhost/avtal/avtalservice.asmx"/>
>     	<seam:component/>
>     </bean>
> fails like this:
> 12:45:35,203 DEBUG [ProxyUtils] Creating proxy for Spring Seam component 'processRepository' using class: se.lantmateriet.wfl.dataaccess.WsProcessRepository
> 12:45:35,282 INFO  [DefaultListableBeanFactory] Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory at 8c2d94: defining beans [org.jboss.seam.ioc.spring.seamComponentPostProcessor,processRepository]; root of factory hierarchy
> 12:45:35,297 ERROR [[/wfl-seam]] Exception sending context initialized event to listener instance of class org.jboss.seam.servlet.SeamListener
> org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'processRepository' defined in ServletContext resource [/WEB-INF/applicationContext.xml]: Initialization of bean failed; nested exception is org.jboss.seam.InstantiationException: Could not instantiate Seam component: processRepository
> 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:430)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:255)
> 	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:156)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:252)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
> 	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:287)
> 	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:689)
> 	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:358)
> 	at org.jboss.seam.ioc.spring.ContextLoader.startupContextLoader(ContextLoader.java:64)
> 	at org.jboss.seam.ioc.spring.ContextLoader.create(ContextLoader.java:43)
> 	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:597)
> 	at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
> 	at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:124)
> 	at org.jboss.seam.Component.callComponentMethod(Component.java:1957)
> 	at org.jboss.seam.Component.callCreateMethod(Component.java:1880)
> 	at org.jboss.seam.Component.newInstance(Component.java:1859)
> 	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:98)
> 	at org.jboss.seam.init.Initialization.init(Initialization.java:508)
> 	at org.jboss.seam.servlet.SeamListener.contextInitialized(SeamListener.java:34)
> 	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3854)
> 	at org.apache.catalina.core.StandardContext.start(StandardContext.java:4359)
> 	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:761)
> 	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:741)
> 	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:553)
> Caused by: org.jboss.seam.InstantiationException: Could not instantiate Seam component: processRepository
> 	at org.jboss.seam.Component.newInstance(Component.java:1853)
> 	at org.jboss.seam.Component.getInstance(Component.java:1756)
> 	at org.jboss.seam.Component.getInstance(Component.java:1735)
> 	at org.jboss.seam.Component.getInstance(Component.java:1729)
> 	at org.jboss.seam.ioc.spring.SeamComponentPostProcessor.postProcessAfterInitialization(SeamComponentPostProcessor.java:49)
> 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:314)
> 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1184)
> 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:407)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:255)
> 	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:156)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:252)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
> 	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:287)
> 	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:689)
> 	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:358)
> 	at org.jboss.seam.ioc.spring.ContextLoader.startupContextLoader(ContextLoader.java:64)
> 	at org.jboss.seam.ioc.spring.ContextLoader.create(ContextLoader.java:43)
> 	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:597)
> 	at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
> 	at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:124)
> 	at org.jboss.seam.Component.callComponentMethod(Component.java:1957)
> 	at org.jboss.seam.Component.callCreateMethod(Component.java:1880)
> 	at org.jboss.seam.Component.newInstance(Component.java:1859)
> 	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:98)
> 	at org.jboss.seam.init.Initialization.init(Initialization.java:508)
> Caused by: java.lang.InstantiationException: se.lantmateriet.wfl.dataaccess.WsProcessRepository_$$_javassist_0
> 	at java.lang.Class.newInstance0(Class.java:340)
> 	at java.lang.Class.newInstance(Class.java:308)
> 	at org.jboss.seam.ioc.ProxyUtils.enhance(ProxyUtils.java:71)
> 	at org.jboss.seam.ioc.IoCComponent.instantiateJavaBean(IoCComponent.java:94)
> 	at org.jboss.seam.Component.instantiate(Component.java:1154)
> 	at org.jboss.seam.Component.newInstance(Component.java:1849)
> 	at org.jboss.seam.Component.getInstance(Component.java:1756)
> 	at org.jboss.seam.Component.getInstance(Component.java:1735)
> 	at org.jboss.seam.Component.getInstance(Component.java:1729)
> 	at org.jboss.seam.ioc.spring.SeamComponentPostProcessor.postProcessAfterInitialization(SeamComponentPostProcessor.java:49)
> 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:314)
> 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1184)
> 	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:407)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:255)
> 	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:156)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:252)
> 	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
> 	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:287)
> 	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:689)
> 	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:358)
> 	at org.jboss.seam.ioc.spring.ContextLoader.startupContextLoader(ContextLoader.java:64)
> 	at org.jboss.seam.ioc.spring.ContextLoader.create(ContextLoader.java:43)
> 	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:597)
> 	at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
> 	at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:124)
> 	at org.jboss.seam.Component.callComponentMethod(Component.java:1957)
> 	at org.jboss.seam.Component.callCreateMethod(Component.java:1880)
> If I change <seam:component/> to <seam:component intercept="false"/> everything works.
> 1. Default for stateless spring beans seems to be true since seam standard rules are applied if intercept is null, that is not defined. bug?
> 2. Why would I want to use intercept="true" anyway? What interceptors will be added?
> 3. Why is it failing with intercept="true"?

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