Category: Development (Page 7 of 18)

As part of detecting side effects across tests, we needed to inspect some objects in tests autowired by spring. Unfortunately these objects were automatically proxied with the current configuration (and needed by some tests) so we needed some way of accessing the underlying proxied objects.

We didn’t really find many good examples of how to go about bypassing the spring proxies created through AOP. Doing a bit of debugging we found that spring used CGLib to generate its proxies and there is fortunately a method made accessible called getTargetSource() that gives you the underlying object. Here’s the helper class we wrote to extract it.

public class CglibHelper {
    private final Object proxied;

    public CglibHelper(Object proxied) {
        this.proxied = proxied;
    }

    public Object getTargetObject() {
        String name = proxied.getClass().getName();
        if (name.toLowerCase().contains("cglib")) {
            return extractTargetObject(proxied);
        }
        return proxied;
    }

    private Object extractTargetObject(Object proxied) {
        try {
            return findSpringTargetSource(proxied).getTarget();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private TargetSource findSpringTargetSource(Object proxied) {
        Method[] methods = proxied.getClass().getDeclaredMethods();
        Method targetSourceMethod = findTargetSourceMethod(methods);
        targetSourceMethod.setAccessible(true);
        try {
            return (TargetSource)targetSourceMethod.invoke(proxied);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private Method findTargetSourceMethod(Method[] methods) {
        for (Method method : methods) {
            if (method.getName().endsWith("getTargetSource")) {
                return method;
            }
        }
        throw new IllegalStateException(
                "Could not find target source method on proxied object [" 
                        + proxied.getClass() + "]");
    }
}

One of the major troubles with integration tests are the tradeoffs you get with speed and feedback. As systems get larger, the more integration tests you have, and the more chance you might preserve state. I’ve been fighting a build inherited by our team where intermittent integration tests prove troublesome. In the next series of posts, I’ll detail some of the issues we’ve found and some of the fixes.

Our current system uses JMS for messaging and one of the first stateful problems we found were messages being left over from previous test runs in our ActiveMQ instance. We had a few options for doing it out of memory including a purge script and a call to deleteAllMessages though the latter failed because we stored messages only in memory.

Instead we worked out how it stores messages, and wrote a class to go through and clean them all up.

public class ActiveMqHelper {

    public void removeAllMessages() {
        Map<String,BrokerService> brokers = BrokerRegistry
                .getInstance().getBrokers();
        try {
            for (BrokerService brokerService : brokers.values()) {
                Broker broker = brokerService.getBroker();
                new ActiveMQBrokerExtension(broker).clearAllMessages();
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private class ActiveMQBrokerExtension {
        private final Broker broker;

        public ActiveMQBrokerExtension(Broker broker) {
            this.broker = broker;
        }

        public void clearAllMessages() throws Exception {
            Map<ActiveMQDestination, Destination> destinationMap 
                = broker.getDestinationMap();
            for (Destination destination : destinationMap.values()) {
                ActiveMQDestination activeMQDestination 
                        = destination.getActiveMQDestination();
                if (activeMQDestination.isTopic()) {
                    clearAllMessages((Topic)destination);
                } else if (activeMQDestination.isQueue()) {
                    clearAllMessages((Queue) destination);
                }
            }
        }

        private void clearAllMessages(Topic topic) throws IOException {
            List<Subscription> consumers = topic.getConsumers();
            for (Subscription consumer : consumers) {
                ConnectionContext consumerContext = consumer.getContext();
                MessageStore messageStore = topic.getMessageStore();
                messageStore.removeAllMessages(consumerContext);
            }
        }
        private void clearAllMessages(Queue queue) throws Exception {
            queue.purge();
        }
    }
}

Someone might one day benefit from this.