How to set up XML marshalling for a TCP server in Spring integration?

Question

I want to use spring integration to create a simple TCP server that communicates using XML messages. I trying to use a TcpInboundGateway with appropriate marshalling set up on the input and output channels as below.

@Bean
TcpNetServerConnectionFactory cf () {

    TcpNetServerConnectionFactory tcf = new TcpNetServerConnectionFactory(7017);
    tcf.setSerializer(new ByteArrayLfSerializer());
    return tcf;
}

@Bean
TcpInboundGateway tcpGate() {
    TcpInboundGateway gateway = new TcpInboundGateway();
    gateway.setConnectionFactory(cf());
    gateway.setRequestChannel(requestChannel());
    gateway.setReplyChannel(replyChannel());
    return gateway;
}

@Bean
public MessageChannel requestChannel() {
    return new DirectChannel();
}

@Bean
public MessageChannel replyChannel() {
    return new DirectChannel();
}



@Bean 
Jaxb2Marshaller marshaller()
{
    final Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
    marshaller.setPackagesToScan("uk.ac.man.jb.emerlin.emms.corrcontrol.messages");
    return marshaller;
}


@Bean
@org.springframework.integration.annotation.Transformer(inputChannel="requestChannel", outputChannel="requestChannel")
public Transformer unmarshallingTransformer()
{
    final UnmarshallingTransformer unmarshallingTransformer = new UnmarshallingTransformer(marshaller());

    unmarshallingTransformer.setSourceFactory(msourceFactory());
    return  unmarshallingTransformer;
}

@Bean
@org.springframework.integration.annotation.Transformer(inputChannel="replyChannel", outputChannel="replyChannel")
public Transformer marshallingTransformer() throws ParserConfigurationException
{
    final MarshallingTransformer marshallingTransformer = new MarshallingTransformer(marshaller());
    marshallingTransformer.setResultType(AbstractXmlTransformer.STRING_RESULT);
    return  marshallingTransformer;
}

@Bean
public SourceFactory msourceFactory() {
    return new SourceFactory() {

        @Override
        public Source createSource(Object payload) {
            Source source = null;
            if (payload instanceof String) {
                source = new StreamSource(new StringReader((String) payload));
            }
            else if (payload instanceof byte[]) {
                source = new StreamSource(new StringReader(new String((byte[])payload)));
            }
            if (source == null) {
                throw new MessagingException("failed to create Source for payload type [" +
                        payload.getClass().getName() + "]");
            }
            return source;

        }
    };

}



//FIXME 
@MessageEndpoint
public static class CorrelatorEmControl {

    @ServiceActivator(inputChannel = "requestChannel" , outputChannel="replyChannel")
    public CorrelatorResponse service(@Payload CorrelatorRequest in) {
        logger.info("command {}", in.getCommand().getName()); 
        return new CorrelatorResponse();
    }
}

My problem is that although the incoming message is unmarshalled properly I cannot seem to get the marshalling of the response into an appropriate form - e.g. a string for the response channel to pass it on - as in the following trace.

14:20:37.277 [pool-3-thread-2] INFO  u.a.m.j.e.e.c.d.CorrelatorEndpoint - command silly
14:20:37.277 [pool-3-thread-2] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Returning cached instance of singleton bean 'replyChannel'
14:20:37.277 [pool-3-thread-2] DEBUG o.s.i.t.MessageTransformingHandler - correlatorEndpoint.marshallingTransformer.transformer.handler received message: GenericMessage [payload=uk.ac.man.jb.emerlin.emms.corrcontrol.messages.CorrelatorResponse@74056889, headers={timestamp=1429881637277, id=d745c519-ddd3-a92c-260f-22e91fdcc5d1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_tcp_remotePort=55208, ip_address=0:0:0:0:0:0:0:1, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_hostname=localhost, ip_connectionId=localhost:55208:7017:8d710c70-ed34-4b3a-bdb6-d3ae9ce7142c}]
14:20:37.292 [pool-3-thread-2] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Returning cached instance of singleton bean 'replyChannel'
14:20:37.292 [pool-3-thread-2] DEBUG o.s.i.handler.BridgeHandler - org.springframework.integration.handler.BridgeHandler@304044a3 received message: GenericMessage [payload=<?xml version="1.0" encoding="UTF-8" standalone="yes"?><emcc:correlatorResponse xmlns:emcc="http://jb.man.ac.uk/schema/emerlincorrelator" xmlns:eop="http://jb.man.ac.uk/schema/eop"><errorStatus>false</errorStatus></emcc:correlatorResponse>, headers={timestamp=1429881637292, id=20e4eaf1-f6d0-de23-c14b-1dde7df5939d, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_address=0:0:0:0:0:0:0:1, ip_tcp_remotePort=55208, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_hostname=localhost, ip_connectionId=localhost:55208:7017:8d710c70-ed34-4b3a-bdb6-d3ae9ce7142c}]
14:20:37.293 [pool-3-thread-2] DEBUG o.s.i.channel.DirectChannel - postSend (sent=true) on channel 'replyChannel', message: GenericMessage [payload=<?xml version="1.0" encoding="UTF-8" standalone="yes"?><emcc:correlatorResponse xmlns:emcc="http://jb.man.ac.uk/schema/emerlincorrelator" xmlns:eop="http://jb.man.ac.uk/schema/eop"><errorStatus>false</errorStatus></emcc:correlatorResponse>, headers={timestamp=1429881637292, id=20e4eaf1-f6d0-de23-c14b-1dde7df5939d, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_address=0:0:0:0:0:0:0:1, ip_tcp_remotePort=55208, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_hostname=localhost, ip_connectionId=localhost:55208:7017:8d710c70-ed34-4b3a-bdb6-d3ae9ce7142c}]
14:20:37.293 [pool-3-thread-2] DEBUG o.s.i.channel.DirectChannel - postSend (sent=true) on channel 'replyChannel', message: GenericMessage [payload=uk.ac.man.jb.emerlin.emms.corrcontrol.messages.CorrelatorResponse@74056889, headers={timestamp=1429881637277, id=d745c519-ddd3-a92c-260f-22e91fdcc5d1, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_tcp_remotePort=55208, ip_address=0:0:0:0:0:0:0:1, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_hostname=localhost, ip_connectionId=localhost:55208:7017:8d710c70-ed34-4b3a-bdb6-d3ae9ce7142c}]
14:20:37.293 [pool-3-thread-2] DEBUG o.s.i.channel.DirectChannel - postSend (sent=true) on channel 'requestChannel', message: GenericMessage [payload=uk.ac.man.jb.emerlin.emms.corrcontrol.messages.CorrelatorRequest@44391778, headers={timestamp=1429881637275, id=862128b7-9754-124b-e6a2-407f87d0407c, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_address=0:0:0:0:0:0:0:1, ip_tcp_remotePort=55208, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_hostname=localhost, ip_connectionId=localhost:55208:7017:8d710c70-ed34-4b3a-bdb6-d3ae9ce7142c}]
14:20:37.293 [pool-3-thread-2] DEBUG o.s.i.channel.DirectChannel - postSend (sent=true) on channel 'requestChannel', message: GenericMessage [payload=byte[254], headers={timestamp=1429881637257, id=963a80b6-ac0f-35db-51d1-a52593f9b78c, errorChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_tcp_remotePort=55208, ip_address=0:0:0:0:0:0:0:1, replyChannel=org.springframework.messaging.core.GenericMessagingTemplate$TemporaryReplyChannel@110ed52e, ip_hostname=localhost, ip_connectionId=localhost:55208:7017:8d710c70-ed34-4b3a-bdb6-d3ae9ce7142c}]
14:20:37.294 [pool-3-thread-2] DEBUG o.s.i.i.t.s.ByteArrayCrLfSerializer - Available to read:0
14:20:37.293 o.s.i.ip.tcp.TcpInboundGateway - Failed to send reply
org.springframework.messaging.MessageHandlingException: When using a byte array serializer, the socket mapper expects either a byte array or String payload, but received: class org.springframework.xml.transform.StringResult

How can I configure the transformer to produce an appropriate output - the StringResult does not seem to be interpreted properly?

score 0 · Accepted Answer · answered Apr 26 '15 at 08:29

0

By default, the marshalling transformer produces a javax.xml.transform.Result object; the transformer has an optional ResultTransformer taken as a second constructor argument.

Configure it to use a ResultToStringTransformer to convert the Result to a String.

answered Apr 26 '15 at 08:29

Gary Russell

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Thanks - that worked - cannot upvote though as I do not have enough reputation! – Paul Harrison Apr 27 '15 at 08:42
You should be able to mark the answer as accepted, though - this will help others (click the check-mark outline below the voting buttons). – Gary Russell Apr 27 '15 at 09:04

How to set up XML marshalling for a TCP server in Spring integration?

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