Help with integration of custom beans xml format

[CameronBraid]

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 {
    ...
    public void afterPropertiesSet() throws Exception {
        
        // validation of properties here
        
        BeanDefinitionRegistry registry = null;
        
        if (parentContext instanceof ConfigurableApplicationContext) {
            // merge the bean befinitions into the parent's registry
           BeanFactory beanFactory = ((ConfigurableApplicationContext)parentContext).getBeanFactory();
            if (beanFactory instanceof BeanDefinitionRegistry) {
                registry = (BeanDefinitionRegistry)beanFactory;
                new ActiveMQBeanDefinitionReader(registry).loadBeanDefinitions(location);
            }
        }
        
        // handle (registry == null) case
        
    }

}

This code causes an exception

java.util.ConcurrentModificationException
	at java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:552)
	at java.util.LinkedList$ListItr.next(LinkedList.java:488)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:198)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:279)
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>&#40;ClassPathXmlApplicationContext.java&#58;81&#41;
	at org.springframework.context.support.ClassPathXmlApplicationContext.<init>&#40;ClassPathXmlApplicationContext.java&#58;66&#41;
	at org.springframework.context.support.ClassPathXmlApplicationContext.<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]

After a bit of chat on the ActiveMQ irc 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