Spring integration java DSL Dispatcher has no subscribers - spring-boot

Question

I keep getting the below exception even after adding the subscriber to my channel i.e orderDeliveredChannel.
I am converting the XML configuration to Spring Integration java DSL.
Below is the exception i am getting while running the application.
2019-11-10 13:47:14.520 INFO 24598 --- [ask-scheduler-3] o.s.integration.handler.LoggingHandler : GenericMessage [payload=study.pattern.integration.lab9.domain.Order#776f7ea6, headers={sequenceNumber=2, correlationId=4b4dbb88-3fe7-1fa9-81a6-6e438baabac2, id=faada063-924f-f9c9-35f0-9771158e6180, sequenceSize=3, timestamp=1573364834520}]
2019-11-10 13:47:14.522 ERROR 24598 --- [ask-scheduler-3] o.s.integration.handler.LoggingHandler : org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'application.orderDeliveredChannel'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=study.pattern.integration.lab9.domain.Order#776f7ea6, headers={sequenceNumber=2, correlationId=4b4dbb88-3fe7-1fa9-81a6-6e438baabac2, id=faada063-924f-f9c9-35f0-9771158e6180, sequenceSize=3, timestamp=1573364834520}], failedMessage=GenericMessage [payload=study.pattern.integration.lab9.domain.Order#776f7ea6, headers={sequenceNumber=2, correlationId=4b4dbb88-3fe7-1fa9-81a6-6e438baabac2, id=faada063-924f-f9c9-35f0-9771158e6180, sequenceSize=3, timestamp=1573364834520}]
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:77)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:453)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:403)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:444)
at org.springframework.integration.handler.AbstractMessageProducingHandler.doProduceOutput(AbstractMessageProducingHandler.java:318)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:266)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:229)
at org.springframework.integration.aggregator.AbstractCorrelatingMessageHandler.completeGroup(AbstractCorrelatingMessageHandler.java:851)
at org.springframework.integration.aggregator.AbstractCorrelatingMessageHandler.processMessageForGroup(AbstractCorrelatingMessageHandler.java:498)
at org.springframework.integration.aggregator.AbstractCorrelatingMessageHandler.handleMessageInternal(AbstractCorrelatingMessageHandler.java:471)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:170)
at org.springframework.integration.dispatcher.AbstractDispatcher.tryOptimizedDispatch(AbstractDispatcher.java:115)
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:133)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:453)
at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:403)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:187)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:166)
at org.springframework.messaging.core.GenericMessagingTemplate.doSend(GenericMessagingTemplate.java:47)
at org.springframework.messaging.core.AbstractMessageSendingTemplate.send(AbstractMessageSendingTemplate.java:109)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutput(AbstractMessageProducingHandler.java:444)
at org.springframework.integration.handler.AbstractMessageProducingHandler.doProduceOutput(AbstractMessageProducingHandler.java:318)
at org.springframework.integration.handler.AbstractMessageProducingHandler.produceOutput(AbstractMessageProducingHandler.java:266)
at org.springframework.integration.handler.AbstractMessageProducingHandler.sendOutputs(AbstractMessageProducingHandler.java:229)
at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:133)
at org.springframework.integration.handler.AbstractMessageHandler.handleMessage(AbstractMessageHandler.java:170)
at org.springframework.integration.endpoint.PollingConsumer.handleMessage(PollingConsumer.java:143)
at org.springframework.integration.endpoint.AbstractPollingEndpoint.messageReceived(AbstractPollingEndpoint.java:396)
at org.springframework.integration.endpoint.AbstractPollingEndpoint.doPoll(AbstractPollingEndpoint.java:380)
at org.springframework.integration.endpoint.AbstractPollingEndpoint.pollForMessage(AbstractPollingEndpoint.java:328)
at org.springframework.integration.endpoint.AbstractPollingEndpoint.lambda$null$1(AbstractPollingEndpoint.java:275)
at org.springframework.integration.util.ErrorHandlingTaskExecutor.lambda$execute$0(ErrorHandlingTaskExecutor.java:57)
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50)
at org.springframework.integration.util.ErrorHandlingTaskExecutor.execute(ErrorHandlingTaskExecutor.java:55)
at org.springframework.integration.endpoint.AbstractPollingEndpoint.lambda$createPoller$2(AbstractPollingEndpoint.java:272)
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=study.pattern.integration.lab9.domain.Order#776f7ea6, headers={sequenceNumber=2, correlationId=4b4dbb88-3fe7-1fa9-81a6-6e438baabac2, id=faada063-924f-f9c9-35f0-9771158e6180, sequenceSize=3, timestamp=1573364834520}]
at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:139)
at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:106)
at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:73)
... 48 more
Here is the my spring integration configuration
package study.pattern.integration.lab9.config;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.annotation.IntegrationComponentScan;
import org.springframework.integration.annotation.ServiceActivator;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.channel.QueueChannel;
import org.springframework.integration.config.EnableIntegration;
import org.springframework.integration.dsl.IntegrationFlow;
import org.springframework.integration.dsl.IntegrationFlows;
import org.springframework.integration.dsl.MessageChannels;
import org.springframework.integration.dsl.Pollers;
import org.springframework.integration.handler.LoggingHandler;
import org.springframework.messaging.MessageHandler;
import lombok.extern.slf4j.Slf4j;
import study.pattern.integration.lab9.domain.ItemType;
import study.pattern.integration.lab9.domain.Order;
import study.pattern.integration.lab9.domain.OrderItem;
import study.pattern.integration.lab9.service.OrderDelivery;
import study.pattern.integration.lab9.service.OrderItemsProcessor;
#EnableIntegration
#Configuration
#IntegrationComponentScan
#Slf4j
public class IntegrationConfiguration {
#Autowired
OrderItemsProcessor processor;
#Autowired
OrderDelivery orderDelivery;
#Bean
#Qualifier("orderChannel")
public DirectChannel orderChannel() {
return MessageChannels.direct().get();
}
#Bean
#Qualifier("orderItemsChannel")
public DirectChannel orderItemsChannel() {
return MessageChannels.direct().get();
}
/**
*
*
* QueueChannel: Implements PollableChannel.
* There’s one endpoint connected to the channel, no subscribers. This communication is asynchronous;
* the receiver will retrieve the message through a different thread. How it works:
The producer sends the message to the channel.
The channel queues the message.
The consumer actively retrieves the message (active receiver).
* #return
*/
#Bean
#Qualifier("musicItemsChannel")
public QueueChannel musicItemsChannel() {
return MessageChannels.queue().get();
}
#Bean
#Qualifier("softwareItemsChannel")
public QueueChannel softwareItemsChannel() {
return MessageChannels.queue().get();
}
#Bean
#Qualifier("booksItemChannel")
public QueueChannel booksItemsChannel() {
return MessageChannels.queue().get();
}
#Bean
#Qualifier("orderItemsProcessed")
public DirectChannel orderItemsProcessedChannel() {
return MessageChannels.direct().get();
}
#Bean
#Qualifier("orderDelivered")
public DirectChannel orderDeliveredChannel() {
return MessageChannels.direct().get();
}
#Bean
#ServiceActivator(inputChannel = "myLogChannel")
public MessageHandler logger() {
LoggingHandler loggingHandler = new LoggingHandler(LoggingHandler.Level.INFO.name());
loggingHandler.setLoggerName("logging");
return loggingHandler;
}
#Bean
IntegrationFlow processOrderFlow() {
return IntegrationFlows
.from(orderChannel())
.split(Order.class , a -> a.getOrderItems())
.channel(orderItemsChannel())
.wireTap(f -> f.handle(logger()))
.route(OrderItem.class,
o -> o.getType().name(),
type -> type.channelMapping(ItemType.BOOK.name(),booksItemsChannel())
.channelMapping(ItemType.MUSIC_CD.name(), musicItemsChannel())
.channelMapping(ItemType.SOFTWARE.name(), softwareItemsChannel())
)
.get();
}
#Bean
IntegrationFlow processBooksItemChannel() {
return IntegrationFlows.from(booksItemsChannel())
.handle(processor,"processBooksOrderItem",spec -> spec.poller(Pollers.fixedDelay(100l)))
.channel(orderItemsProcessedChannel())
// .wireTap(f -> f.handle(logger()))
.log()
.get();
}
#Bean
IntegrationFlow processMusicItemChannel() {
return IntegrationFlows.from(musicItemsChannel())
.handle(processor,"processMusicOrderItem",spec -> spec.poller(Pollers.fixedDelay(100l)))
.channel(orderItemsProcessedChannel())
// .wireTap(f -> f.handle(logger()))
.log()
.get();
}
#Bean
IntegrationFlow processSoftwareItemChannel() {
return IntegrationFlows.from(softwareItemsChannel())
.handle(processor, "processSoftware", spec -> spec.poller(Pollers.fixedDelay(100l)))
.channel(orderItemsProcessedChannel())
// .wireTap(f -> f.handle(logger()))
.log()
.get();
}
#Bean
IntegrationFlow aggreateAllProcessedOrderItems() {
return IntegrationFlows.from(orderItemsProcessedChannel())
.aggregate(spec -> spec.processor(orderDelivery, "delivery"))
.channel(orderDeliveredChannel())
.handle(m -> log.info("The Payload data {} ",m.getPayload()))
.log()
.get();
}
}
I am in last step to finish the XML to java DSL configuration.
Can some one please help how to fix this problem.

Answer 1

Your problem is here:
.handle(m -> log.info("The Payload data {} ",m.getPayload()))
.log()
You just can't use a log interceptor when there is no channel any more. I'm saying that because that handle() is a one-way component and there is nothing to send as a reply and, therefore, an output channel is not going to be created for that log interception.
It is not clear what Spring Integration version you have, but in the current on we have a protection against this misconfiguration:
throw new BeanCreationException("The 'currentComponent' (" + currComponent +
") is a one-way 'MessageHandler' and it isn't appropriate to configure 'outputChannel'. " +
"This is the end of the integration flow.");
Therefore your mistake is going to be reject immediately on the parsing phase!