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CameronBraid
Aug 16th, 2004, 11:28 AM
I am trying to help the ActiveMQ people with integration of their configuration file format into a spring application context.

Currently they use a custom XmlBeanDefinitionReader that uses XSLT to transform their xml file format into a normal spring format.

This works fine when someone loads their configuration by instantiating a ActiveMQBeanFactory instance (which uses ActiveMQBeanDefinitionReader internally)

The issue that I am facing is the integration of this process with a normal applicationContext.xml file.

I want to merge the bean definitions from a transfomed ativeMQ.xml file into an existing application context. How can this be done ?

I attempted to do it with :



<bean id="activeMQ" class="ActiveMQ">
<property name="location"><value>classpath&#58;activeMQ.xml</value></property>
</bean>


class ActiveMQ implements InitializingBean, ApplicationContextAware &#123;
...
public void afterPropertiesSet&#40;&#41; throws Exception &#123;

// validation of properties here

BeanDefinitionRegistry registry = null;

if &#40;parentContext instanceof ConfigurableApplicationContext&#41; &#123;
// merge the bean befinitions into the parent's registry
BeanFactory beanFactory = &#40;&#40;ConfigurableApplicationContext&#41;parentContext&#41;.ge tBeanFactory&#40;&#41;;
if &#40;beanFactory instanceof BeanDefinitionRegistry&#41; &#123;
registry = &#40;BeanDefinitionRegistry&#41;beanFactory;
new ActiveMQBeanDefinitionReader&#40;registry&#41;.loadBeanDef initions&#40;location&#41;;
&#125;
&#125;

// handle &#40;registry == null&#41; case

&#125;

&#125;


This code causes an exception


java.util.ConcurrentModificationException
at java.util.LinkedList$ListItr.checkForComodificatio n&#40;LinkedList.java&#58;552&#41;
at java.util.LinkedList$ListItr.next&#40;LinkedList.java&#58; 488&#41;
at org.springframework.beans.factory.support.DefaultL istableBeanFactory.preInstantiateSingletons&#40;Defaul tListableBeanFactory.java&#58;198&#41;
at org.springframework.context.support.AbstractApplic ationContext.refresh&#40;AbstractApplicationContext.ja va&#58;279&#41;
at org.springframework.context.support.ClassPathXmlAp plicationContext.<init>&#40;ClassPathXmlApplicationContext.java&#58;81&#41;
at org.springframework.context.support.ClassPathXmlAp plicationContext.<init>&#40;ClassPathXmlApplicationContext.java&#58;66&#41;
at org.springframework.context.support.ClassPathXmlAp plicationContext.<init>&#40;ClassPathXmlApplicationContext.java&#58;57&#41;
at Main.main&#40;Main.java&#58;13&#41;


I have also considered making a child context, and load the activeMQ definitions into there, but the problem is that some beans defined in activeMQ.xml may be needed in the parent context.

Any thoughts / ideas / suggestions ?

jstrachan
Aug 16th, 2004, 12:39 PM
After a bit of chat on the ActiveMQ irc (irc://irc.codehaus.org/activemq) we've figured this one out.

The ActiveConnectionFactory is gonna have a property of the broker, then we'll use a BrokerFactoryBean which can take a Spring Resource as a constructor / property to allow Spring to configure the broker on a connection factory - yet keeping the broker XML config file separate to the normal Spring XML configuration.

This allows us to use a custom XMLBeanFactory for the ActiveMQ broker - such as to take advantage of our customized ActiveMQ config file format (to save typing, using elements like broker, connection, transport etc).

So I think we've got this one sorted now