Problem with pub-sub channel routing

[Frank DiMauro]

Hi,

I am having a problem getting a header from a pub-sub channel that get it's message from a web service inbound gateway. I have this working when the message is from a tcp-inbound-channel-adapter. So I am following a working pattern. I get the following error message when I try to get a header from the ws:inbound-gateway's request-channel:

09:07:12,018 WARN [MarshallingWebServiceInboundGateway] failure occurred in gateway sendAndReceive
org.springframework.integration.MessageHandlingExc eption: org.springframework.expression.spel.SpelEvaluation Exception: EL1004Epos 8): Method call: Method setHeader(org.springframework.integration.core.Mes sagingTemplate$TemporaryReplyChannel) cannot be found on com.intrado.isg2.bl.SaveHeader type

Here is the part of my config that is part of this issue:

	<!-- SNR Socket section -->

	<!-- Out-bound Message channel -->
	<int:channel id="tcpSNRSend">
	</int:channel>
		 	
	<!-- Opens a socket on the host/port specified and creates a connection factory -->
	<int-ip:tcp-connection-factory id="cfSNRClient"
		type="client" 
		host="10.100.211.80"
		port="10854"  
		deserializer="connectionSerializeDeserialize" 
	/>
	
	<int-ip:tcp-outbound-channel-adapter
		id="tcpSNROutbound" channel="tcpSNRSend" connection-factory="cfSNRClient" />
		
	<int-ip:tcp-inbound-channel-adapter
		id="tcpSNRInbound" channel="tcpSNRReceive" connection-factory="cfSNRClient" />	
		
	<int:publish-subscribe-channel id="channelSourceRegInput">
	    <int:interceptors>
	        <int:wire-tap channel="logger" />
	    </int:interceptors>
	</int:publish-subscribe-channel>
	
	<int:channel id="channelSourceRegOutput">
	    <int:interceptors>
	        <int:wire-tap channel="logger" />
	    </int:interceptors>
	</int:channel>
	
 	<int-ws:inbound-gateway id="wsSourceRegistration" 
				request-channel="channelSourceRegInput"
				reply-channel="channelSourceRegOutput"
				marshaller="xmlBeansMarshaller"
				unmarshaller="xmlBeansMarshaller" />	
	
	<int:service-activator id="sourceRegRequestService"
						   input-channel="channelSourceRegInput" 
						   output-channel="tcpSNRSend"
						   ref="sourceRegistrationService"
						   method="sourceRegistration"
						   order="2"/>
						   
	<int:service-activator id="sourceRegResponseService"
						   input-channel="tcpSNRReceive" 
						   output-channel="channelSourceRegOutputWithoutHeader"
						   ref="sourceRegistrationService"
						   method="sourceRegistrationResponse"/>						   					   		
	
	<!-- Routes the message received on the input-channel to multiple channels -->
	<int:recipient-list-router input-channel="channelSourceRegInput"
		order="1">
		<int:recipient channel="saveSNRSourceRegHeader" />
	</int:recipient-list-router>

	<int:channel id="saveSNRSourceRegHeader" />

	<!-- Calls the method setHeader on the object rgHeaderSaver with the data 
		from the header replyChannel -->
	<int:chain input-channel="saveSNRSourceRegHeader">
		<int:transformer expression="headers.replyChannel" />
		<int:service-activator ref="snrSourceRegHeaderSaver"
			method="setHeader" />
	</int:chain>
	
	<int:message-history/>
	
	<int:header-enricher input-channel="channelSourceRegOutputWithoutHeader"
		output-channel="channelSourceRegOutput">
		<int:header name="replyChannel" expression="@snrSourceRegHeaderSaver.header" />
	</int:header-enricher>	
	
	<!-- Simple calls with a getter/setter -->
	<bean id="snrSourceRegHeaderSaver" class="com.intrado.isg2.bl.SaveHeader" />		
	
	<!-- This channel will allow multiple subscribers to receive a message from this channel -->
	<int:channel id="tcpSNRReceive" >
		<int:interceptors>
			<int:wire-tap channel="logger"/>
		</int:interceptors>
	</int:channel>

Here is the SaveHeader class

package com.intrado.isg2.bl;

public class SaveHeader {

	private volatile String header;

	public String getHeader() {
		return header;
	}

	public void setHeader(String header) {
		this.header = header;
	}

}

The issue is with the channel "channelSourceRegInput" I am trying to get the replayHeader so I can add it to the message that goes to the channel "channelSourceRegOutput".

I need to know if this error is a bug as I can do this successfully with a tcp adapter.

Thanks,
Frank

[oleg.zhurakousky]

That is because the signature of your setHeader(String) method accepting String type while "headers.replyChannel" expression returns an instance of MessageChannel.
You could change expression to "headers.replyChannel.getComponentName" which will return the name of this channel. However looking at your exception the reply channel is a temporary channel which has no name. Also since your ServiceActivator (SaveHeader.setHeader) is void the flow will end there and the ws:inbound-gateway will hang awaiting for a reply.

Can you explain a little what are you trying to accomplish? Is the idea to store a reply channel so it could be retrieved later when reply is available? How late?. . . .

[Frank DiMauro]

Thanks for the information about the data type mismatch.

Here is what this code is trying to accomplish:
1. Receive a web service call, transform the incoming xml.
2. Send the transformed xml to a server via a socket.
3. Receive the response xml from the server via the socket.
4. Transform the response xml and reply to the web service call.

When I did this WITHOUT a header enhancer the web service gateway threw the error:
org.springframework.integration.support.channel.Ch annelResolutionException: no output-channel or replyChannel header available


I know I am going to loose the web service call headers when I send the message to the tcp socket. So I am trying to get the headers back on the message that is going back out the web service. I did not think I needed to do this. I thought once I placed the message on the web gateway's reply-channel it would sent it out. Instead I got the above exception.

[oleg.zhurakousky]

Then you should use TCP gateways instead of adapters. Remember in Spring Integration Gateways are for bi-directional communication and adapters are uni-directional. So instead of doing what you doing (trying to save a channel) all you need to do is this:
1. ws:inbound-gateway -> Receive a web service call, transform the incoming xml.
2. tcp:outbound-gateway -> Send the transformed xml to a server via a socket
3. no need to do anything since the above component (#2) is a gateway which mens it will produce a reply for "Receive the response xml from the server via the socket."
4 no need to do anything either since reply goes back to ws:inbound-gateway

Hope that clarifies

[Frank DiMauro]

Oleg,

I did that in the first place and it did work but I need the socket connection for other messages as well. So I changed it from a gateway to using 2 tcp adapters. I will receive other unsolicited messages coming in on that socket. I plan on putting a content based router in to handle those other messages.

Any other suggestions for NOT using a tcp gateway in my web service to get this done?

[oleg.zhurakousky]

I am not sure I understand "I need the socket connection for other messages as well". THat is the whole point of the gateway - to correlate responses so you can send as many messages as you want and receive proper replies. In fact you can have many WS gateways all interacting with a single TCP gateway and all will get the correct response. What am I missing?