Proxying a BeanFactory

[jdigger]

How can I proxy an object returned by a FactoryBean? Specificly, I want to put a DebugInterceptor around a RemoteStatelessSessionProxyFactoryBean. The problem is, it puts it around the FactoryBean, not what the FactoryBean returns (the proxy to the EJB)

Here's an example:

<bean id="serviceProxyCreator" class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator" lazy-init="false">
  <property name="beanNames">
    <value>userService,caseService,customerService,contactService</value>
  </property>
  <property name="interceptorNames">
    <list>
      <value>debugInterceptor</value>
    </list>
  </property>
</bean>

<bean id="debugInterceptor" class="org.springframework.aop.interceptor.DebugInterceptor" />

<bean id="userService" class="org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean" lazy-init="true" singleton="true">
  <property name="businessInterface">
    <value>mypackage.UserService</value>
  </property>
  <property name="jndiName">
    <value>UserServiceBean-v1.6.0.0</value>
  </property>
  <property name="jndiTemplate">
    <ref bean="jndiTemplate"/>
  </property>
</bean>

What that produces is entries in my log of:

Debug interceptor: count=1 invocation=[Invocation: method=[public abstract java.lang.Object org.springframework.beans.factory.FactoryBean.getObject() throws java.lang.Exception] args=null] target is of class [org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean]]
Debug interceptor: next returned

... which isn't very helpful.

[irbouho]

To proxy BeanFactory returned Object instead of BeanFactory itself you can apply your interceptors using ProxyFactoryBean:

<bean id="userService" class="org.springframework.aop.framework.ProxyFactoryBean">
  <property name="target">
    <bean class="org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean"> 
      <property name="businessInterface"> 
        <value>mypackage.UserService</value> 
      </property> 
      <property name="jndiName"> 
        <value>UserServiceBean-v1.6.0.0</value> 
      </property> 
      <property name="jndiTemplate"> 
        <ref bean="jndiTemplate"/> 
      </property> 
    </bean>
  </property>
  <property name="interceptorNames">
   <list>
    <value>debugInterceptor</value>
   </list>
  </property>
</bean>

[jdigger]

Thanks for the suggested solution.

That works, but is there no way an autoproxy can be used? I've got a lot of services that I'd rather not have to manually apply the aspects to. :? Not being able to proxy FactoryBeans seems like a pretty significant limitation for the AOP framework considering how important FactoryBeans are to the Spring framework...

[irbouho]

I do not know if this will make things easier for you. You can reduce the typing by using an abstract template and inheriting from it:

<!-- Requires Spring 1.1 -->
<bean id="interceptorStack" class="org.springframework.aop.framework.ProxyFactoryBean" abstract="true">
  <property name="interceptorNames"> 
   <list> 
    <value>debugInterceptor</value> 
    <value>interceptor2</value> 
    <value>interceptor3</value> 
   </list> 
  </property> 
</bean> 

<bean id="userService" parent="interceptorStack">
  <property name="target"> 
    <bean class="org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean"> 
      <property name="businessInterface"> 
        <value>mypackage.UserService</value> 
      </property> 
      <property name="jndiName"> 
        <value>UserServiceBean-v1.6.0.0</value> 
      </property> 
      <property name="jndiTemplate"> 
        <ref bean="jndiTemplate"/> 
      </property> 
    </bean> 
  </property> 
</bean>

[jdigger]

I still think not being able to proxy FactoryBeans is a problem, but the abstract template solution addresses my immediate problem quite well. Thanks!

[jdigger]

btw: As written, that doesn't work -- CGLib complains about not being able to proxy a final class because it's trying to proxy a java.lang.Proxy using Proxy's interface. The solution is to specify the proxyInterfaces to the ProxyFactoryBean.

ie,

<bean id="userService" parent="serviceInterceptorStack">
  <property name="proxyInterfaces">
    <value>mypackage.UserService</value>
  </property>
  <property name="target">
    <bean class="org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean">
      <property name="businessInterface">
        <value>mypackage.UserService</value>
      </property>
      <property name="jndiName">
        <value>UserServiceBean-v1.6.0.0</value>
      </property>
      <property name="jndiTemplate">
        <ref bean="jndiTemplate"/>
      </property>
    </bean>
  </property>
</bean>

That kind of redundancy is annoying, so I overrode ProxyFactoryBean's setBeanFactory method with the following code:

if (getProxiedInterfaces().length == 0) {
  final Class targetClass = getTargetSource().getTargetClass();
  if (java.lang.reflect.Proxy.class.isAssignableFrom(targetClass) ||
      net.sf.cglib.proxy.Proxy.class.isAssignableFrom(targetClass)) {
    final Class[] classes = targetClass.getInterfaces();
    for &#40;int i = 0; i < classes.length; i++&#41; &#123;
      addInterface&#40;classes&#91;i&#93;&#41;;
    &#125;
  &#125;
&#125;

that removes the need to specify the proxyInterfaces in the ProxyFactoryBean definition.

[Rod Johnson]

I've added an issue in JIRA for this: http://opensource.atlassian.com/proj...browse/SPR-337.

I'll try to look at it in the 1.1.2 timeframe. Not sure it's easy to address, but we'll see.

[aidano]

I've added an issue in JIRA for this: http://opensource.atlassian.com/proj...browse/SPR-337.

I'll try to look at it in the 1.1.2 timeframe. Not sure it's easy to address, but we'll see.

Was this ever resolved? The link goes to a non-existent error (not sure if that's a good thing or not!)

[hucmuc]

I've added an issue in JIRA for this: http://opensource.atlassian.com/proj...browse/SPR-337.

I'll try to look at it in the 1.1.2 timeframe. Not sure it's easy to address, but we'll see.

Was this ever resolved? The link goes to a non-existent error (not sure if that's a good thing or not!)

Remove the dot (.) at the end of the jira link. The issue has not been addressed.