Ignore message from a MQ topic from a specific channel - spring-integration

Question

There is a IBM MQ topic which accepts two types of messages Orders and Shipments.
I have a Springboot subscriber app which is interested in subscribing only the Shipment message type.
Below is how I am routing the channel. If the inbound message is neither of above types it will be thrown to errorChannel that I have.
Here if I do not have orderChannel app will throw an error saying no proper channel for the inbound message.
How do I silently ignore the messages of type order here?
#Bean
#ServiceActivator(inputChannel = "routerChannel")
public HeaderValueRouter router() throws Exception {
HeaderValueRouter router = new HeaderValueRouter(messageType);
router.setChannelMapping(shipment, "shipmentChannel");
router.setChannelMapping(order, "orderChannel");
router.setDefaultOutputChannel(invalidHeaderValueChannel);
return router;
}
Currently I have the below code snippet which I need to have just to avoid the error when there was a Order message.
#ServiceActivator(inputChannel = "orderChannel")
public void getInboundOrderMessage(Message<?> message) throws Exception {
logger.info("Inbound Order message...");
String payload = (String) message.getPayload();
logger.info("Order Header: {}, payload: \n{}", pMessage.getHeaders(), payload);
}
Below is how I have the MsgDrivenChannelAdapter defined
#MessageEndpoint
public class MsgDrivenChannelAdapter {
private AbstractMessageListenerContainer messageListenerContainer;
private DirectChannel inboundErrorChannel;
private DirectChannel routerChannel;
public MsgDrivenChannelAdapter(AbstractMessageListenerContainer pMessageListenerContainer,
DirectChannel pInboundErrorChannel,
DirectChannel pRouterChannel) {
this.messageListenerContainer = pMessageListenerContainer;
this.inboundErrorChannel = pInboundErrorChannel;
this.routerChannel = pRouterChannel;
}
#Bean
public IntegrationFlow jmsInboundFlow() throws Exception {
return IntegrationFlows.from(Jms.messageDrivenChannelAdapter(messageListenerContainer)
.errorChannel(inboundErrorChannel))
.channel(routerChannel)
.get();
}
}
Is there anyway I can avoid this? thanks in advance

Answer 1

See this option on the router:
/**
* When true (default), if a resolved channel key does not exist in the channel map,
* the key itself is used as the channel name, which we will attempt to resolve to a
* channel. Set to false to disable this feature. This could be useful to prevent
* malicious actors from generating a message that could cause the message to be
* routed to an unexpected channel, such as one upstream of the router, which would
* cause a stack overflow.
* #param channelKeyFallback false to disable the fall back.
* #since 5.2
*/
public void setChannelKeyFallback(boolean channelKeyFallback) {
So, it does not fallback to the order as a channel name.
Then it will return as null from the mapping and the logic goes like this:
if (!sent) {
getDefaultOutputChannel();
if (this.defaultOutputChannel != null) {
this.messagingTemplate.send(this.defaultOutputChannel, message);
}
else {
throw new MessageDeliveryException(message, "No channel resolved by router '" + this
+ "' and no 'defaultOutputChannel' defined.");
}
}
If you want just to ignore it and don't want to have that MessageDeliveryException, configure a defaultOutputChannel as a nullChannel.
But better to consider a messageSelector for the listener container, so it does not pull messages from a topic which it is not interested in.

Answer 2

This is how I did it to make it work as I wanted. I used filter to fetch only the particular message type
#Bean
public IntegrationFlow jmsInboundFlow() throws Exception {
return IntegrationFlows.from(Jms.messageDrivenChannelAdapter(messageListenerContainer)
.errorChannel(inboundErrorChannel))
.filter(Message.class, m -> m.getHeaders().get("message_type").equals("shipment"))
.channel(routerChannel)
.get();
}