TimerFactoryBean - ClassCastException

[djmh68]

Hi,

I am using Spring 1.2.4 with a scheduled task which works (!) but when I try to get a reference to the bean within the code it produces a class cast exception. I have the following configuration:

<bean id="methodInvokingTask" class="org.springframework.scheduling.timer.Method InvokingTimerTaskFactoryBean">
<property name="targetObject">
<ref local="applicationMonitor"/>
</property>
<property name="targetMethod">
<value>queueSize</value>
</property>
</bean>

<bean id="scheduledTask" class="org.springframework.scheduling.timer.Schedu ledTimerTask">
<property name="delay">
<value>10000</value>
</property>
<property name="period">
<value>5000</value>
</property>
<property name="timerTask">
<ref local="methodInvokingTask"/>
</property>
</bean>

<bean id="timerScheduler" class="org.springframework.scheduling.timer.TimerF actoryBean">
<property name="scheduledTimerTasks">
<list>
<ref bean="scheduledTask"/>
</list>
</property>
</bean>

In the code I have the following (which produces the exception):

org.springframework.scheduling.timer.TimerFactoryB ean timerScheduler = (org.springframework.scheduling.timer.TimerFactory Bean) m_springBeanFactory.getBean("timerScheduler");

Does anyone know why this is happening ?

thanks

[Andreas Senft]

This is, because classes implementing FactoryBean (as is in your case) are treated specially by the BeanFactory/ApplicationContext. On retrieval you won't get the FactoryBean, but the bean it produces.
That said, there is a way to get the FactoryBean itself: You have to prepend the bean-name with an ampersand (e.g. "&timerScheduler"). Maybe you have to xml-escape the ampersand, because it is a special character.

Regards,
Andreas

[djmh68]

thanks Andreas, couldn't actually get hold of the bean using the ampersand, but it is academic, as it works and I don't need to get hold of the FactoryBean.

[Andreas Senft]

Fine

Though you find it academic: With this string you should be able to lookup the factory bean: "& amp;timeScheduler". Just omit the blank between & and amp (seem to be problematic to post xml-entities here).

Regards,
Andreas

[djmh68]

yes managed to specify it in the context file, but couldn't find the right lookup string to use in the code:

These didn't work :

m_springBeanFactory.getBean("&timerScheduler");
m_springBeanFactory.getBean("\\&timerScheduler");

I am probably being really stupid here...

[Andreas Senft]

m_springBeanFactory.getBean("&timerScheduler");

This one should do. It is also specified in the reference manual this way.
What error do you get?

Regards,
Andreas

[djmh68]

ok I have this:

<bean name="&amp;timerScheduler" class="org.springframework.scheduling.timer.TimerF actoryBean">

and this:

org.springframework.scheduling.timer.TimerFactoryB ean timerScheduler = (org.springframework.scheduling.timer.TimerFactory Bean) m_springBeanFactory.getBean("&timerScheduler");

- and I get this error on start up:

org.springframework.beans.factory.NoSuchBeanDefini tionException: No bean named 'timerScheduler' is defined: org.springframework.beans.factory.xml.XmlBeanFacto ry defining beans [...,currentMemoryScheduledTask,&timerScheduler,app licationMonitor,...]; root of BeanFactory hierarchy
at org.springframework.beans.factory.support.DefaultL istableBeanFactory.getBeanDefinition(DefaultListab leBeanFactory.java:349)
at org.springframework.beans.factory.support.Abstract BeanFactory.getMergedBeanDefinition(AbstractBeanFa ctory.java:671)
at org.springframework.beans.factory.support.Abstract BeanFactory.getBean(AbstractBeanFactory.java:198)
at org.springframework.beans.factory.support.Abstract BeanFactory.getBean(AbstractBeanFactory.java:147)

I am using JDK 1.4.2_04 and JBuilder.

[Andreas Senft]

Ah I see.

The bean name in the context has to be defined without &.
Just <bean name="timerScheduler" ... as you had it before.

Only on accessing the bean (when you need the factory) you have to specify "&timerScheduler".

getBean("timerScheduler") returns the produced bean.
getBean("&timerScheduler") returns the factory.

My remark about the xml-escaping was about referencing (not defining) the bean from within the context itself. Maybe I have been unclear about this.

Regards,
Andreas

[djmh68]

yes that works, thanks again

Dan