Queue channel initialized as SubscribableChannel

Question

I have the following application context defined in order to subscribe to 2 RSS feeds and merge the messages in a priority queue ordering by date published:

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:int="http://www.springframework.org/schema/integration"
xmlns:int-feed="http://www.springframework.org/schema/integration/feed"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
        http://www.springframework.org/schema/integration/feed http://www.springframework.org/schema/integration/feed/spring-integration-feed.xsd">
<int-feed:inbound-channel-adapter id="aFeedAdapter" 
                    channel="feedChannel" 
                    auto-startup="true" 
                    url="...">
    <int:poller fixed-rate="10000" max-messages-per-poll="50" />
</int-feed:inbound-channel-adapter>

<int-feed:inbound-channel-adapter id="bFeedAdapter" 
                    channel="feedChannel" 
                    auto-startup="true"
                    url="...">
    <int:poller fixed-rate="10000" max-messages-per-poll="50" />
</int-feed:inbound-channel-adapter>

<int:channel id="feedChannel">
    <int:queue capacity="100" />
</int:channel>

<int:channel id="sortedChannel">
    <int:priority-queue capacity="100" comparator="feedComparator"/>
</int:channel>

<int:bridge input-channel="feedChanel" output-channel="sortedChannel">
    <int:poller fixed-rate="100" />
</int:bridge>

<bean id="feedComparator" class="...FeedComparator" />

However, I get an IllegalArgumentException during the initialization of the application caused by 'feedChannel' being a SubscribableChannel. Here is the stack trace:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.integration.config.ConsumerEndpointFactoryBean#0': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: A poller should not be specified for endpoint 'org.springframework.integration.config.ConsumerEndpointFactoryBean#0', since 'feedChanel' is a SubscribableChannel (not pollable).
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1512)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:521)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:610)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at org.springframework.integration.samples.feed.FeedInboundChannelAdapterSample.runDemo(FeedInboundChannelAdapterSample.java:37)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.IllegalArgumentException: A poller should not be specified for endpoint 'org.springframework.integration.config.ConsumerEndpointFactoryBean#0', since 'feedChanel' is a SubscribableChannel (not pollable).
    at org.springframework.util.Assert.isNull(Assert.java:89)
    at org.springframework.integration.config.ConsumerEndpointFactoryBean.initializeEndpoint(ConsumerEndpointFactoryBean.java:218)
    at org.springframework.integration.config.ConsumerEndpointFactoryBean.afterPropertiesSet(ConsumerEndpointFactoryBean.java:181)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1571)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1509)
    ... 35 more

But the spring-integration reference documentation states that putting a queue element inside the channel definition should produce a PollableChanneldoc. Can anyone explain what I am doing wrong? Is my approach correct in the context of the spring-integration model? I am using version 3.0.1.RELEASE.

Answer 1

The issue what you see can be only in one case: you have somewhere in the config the second definition for feedChannel and it might look like this:

<int:channel id="feedChannel"/>

By default Spring allows to override beans and the last one wins.

Investigate your code to get dir of the second definition