There is definitely something I must be missing so seeking help here.
I am building a simple REST application using Spring Integration with the following HTTP inbound gateway:
<!-- Gateway -->
<int-http:inbound-gateway id="fruitQuotePOSTGateway"
request-channel="fruitQuotePOSTRequests"
supported-methods="POST"
path="/api/v1/fruit-quote"
request-payload-type="java.lang.String"
reply-timeout="10000"
reply-channel="fruitQuotePOSTResponses"
error-channel="applicationErrors">
<int-http:request-mapping consumes="application/xml" produces="application/xml"/>
</int-http:inbound-gateway>
Once a XML enters this gateway, it undergoes the following simple steps:
- Transformation to generate the JAXB object corresponding to the incoming request
- Message header enrichment that reads a "uuid" from the JAXB Object and sets it to the header of the SI (Spring Integration) message
- Transformation to generate a XML response to the calling client.
To start with, here is the XML configuration of the entire application (omitted the HTTP namespaces, for brevity):
<!-- Gateway -->
<int-http:inbound-gateway id="fruitQuotePOSTGateway"
request-channel="fruitQuotePOSTRequests"
supported-methods="POST"
path="/api/v1/fruit-quote"
request-payload-type="java.lang.String"
reply-timeout="10000"
reply-channel="fruitQuotePOSTResponses"
error-channel="applicationErrors">
<int-http:request-mapping consumes="application/xml" produces="application/xml"/>
</int-http:inbound-gateway>
<!--
- Generate fruit quote request JAXB from the incoming request
- Create a header "requestUUID" by reading it from fruit quote request JAXB
- Generate fruit quote acknowledgement response for the calling client
-->
<int:transformer input-channel="fruitQuotePOSTRequests"
ref="fruitQuoteTransformation"
method="generateFruitQuoteRequestJAXB"/>
<int:header-enricher input-channel="requestUUIDEnrichment" output-channel="orderIDGeneration">
<int:header name="requestUUID" expression="payload.getFruitQuoteRequestJAXB().getFRUITQUOTEREQUESTDATA().getUuid()"/>
</int:header-enricher>
<int:transformer input-channel="fruitQuoteAcknowledgementGeneration"
ref="fruitQuoteTransformation"
method="generateFruitQuoteAcknowledgement"
output-channel="fruitQuotePOSTResponses"/>
<!-- Error handling -->
<int:transformer input-channel="applicationErrors"
ref="fruitQuoteTransformation"
method="generateFruitQuoteAcknowledgementWithError"
output-channel="fruitQuotePOSTResponses"/>
<!-- Channels -->
<int:channel id="fruitQuotePOSTRequests"/>
<int:channel id="requestUUIDEnrichment"/>
<int:channel id="fruitQuotePOSTResponses"/>
<int:channel id="fruitQuoteAcknowledgementGeneration"/>
<int:channel id="applicationErrors"/>
The payload flowing from one step to another in the application is a custom Builder Object as follows (omitted the package name):
import static java.util.Objects.nonNull;
public class FruiteQuoteComposite {
private final FRUITQUOTEREQUEST fruitQuoteRequestJAXB;
private final FruitQuoteApplicationException fruitQuoteApplicationException;
private final Integer orderID;
private final ErrorInformation errorInformation;
private FruiteQuoteComposite(FruiteQuoteCompositeBuilder fruiteQuoteCompositeBuilder) {
this.fruitQuoteRequestJAXB = fruiteQuoteCompositeBuilder.fruitQuoteRequestJAXB;
this.fruitQuoteApplicationException = fruiteQuoteCompositeBuilder.fruitQuoteApplicationException;
this.orderID = fruiteQuoteCompositeBuilder.orderID;
this.errorInformation = fruiteQuoteCompositeBuilder.errorInformation;
}
public FruitQuoteApplicationException getFruitQuoteApplicationException() {
return fruitQuoteApplicationException;
}
public FRUITQUOTEREQUEST getFruitQuoteRequestJAXB() {
return fruitQuoteRequestJAXB;
}
public Integer getOrderID() {
return orderID;
}
public ErrorInformation getErrorInformation() {
return errorInformation;
}
public static class FruiteQuoteCompositeBuilder {
private FRUITQUOTEREQUEST fruitQuoteRequestJAXB;
private FruitQuoteApplicationException fruitQuoteApplicationException;
private Integer orderID;
private ErrorInformation errorInformation;
public FruiteQuoteCompositeBuilder() {
}
public FruiteQuoteCompositeBuilder setFruitQuoteRequestJAXB(FRUITQUOTEREQUEST fruitQuoteRequestJAXB) {
if (nonNull(fruitQuoteRequestJAXB)) {
this.fruitQuoteRequestJAXB = fruitQuoteRequestJAXB;
}
return this;
}
public FruiteQuoteCompositeBuilder setFruitQuoteApplicationException(FruitQuoteApplicationException fruitQuoteApplicationException) {
if (nonNull(fruitQuoteApplicationException)) {
this.fruitQuoteApplicationException = fruitQuoteApplicationException;
}
return this;
}
public FruiteQuoteCompositeBuilder setOrderID(Integer orderID) {
if(nonNull(orderID)) {
this.orderID = orderID;
}
return this;
}
public FruiteQuoteCompositeBuilder setErrorInformation(ErrorInformation errorInformation) {
if (nonNull( errorInformation )) {
this.errorInformation = errorInformation;
}
return this;
}
public FruiteQuoteComposite build() {
return new FruiteQuoteComposite(this);
}
}
}
The reason why I didn't use "output-channel" on the transformers is because I wanted to explicitly choose the replyChannel/outgoing route inside the java logic running the transformation.
For instance, inside the FruitQuoteTransformation.generateFruitQuoteRequestJAXB method, I set one route for success and another route for exceptions/errors as follows:
public Message<FruiteQuoteComposite> generateFruitQuoteRequestJAXB(Message<String> fruitQuoteRequestMessage) {
String fruitQuoteRequest = fruitQuoteRequestMessage.getPayload();
Unmarshaller unmarshaller;
FRUITQUOTEREQUEST fruitQuoteRequestJAXB;
try {
unmarshaller = requireNonNull(fruitQuoteRequestJaxbContext).createUnmarshaller();
fruitQuoteRequestJAXB = (FRUITQUOTEREQUEST) requireNonNull(unmarshaller)
.unmarshal(new StringReader(fruitQuoteRequest));
} catch (JAXBException jaxbException) {
logger.error("JAXB Unmarshalling exception occurred with error code :: " + ERR_FRUIT_QUOTE_REQUEST_JAXB_TRANSFORMATION, jaxbException);
FruitQuoteApplicationException fruitQuoteApplicationException = generateFruitQuoteApplicationException(ERR_FRUIT_QUOTE_REQUEST_JAXB_TRANSFORMATION, MESSAGE_FRUIT_QUOTE_INTERNAL_SYSTEM_ERROR);
FruiteQuoteComposite outboundFruitQuoteComposite = new FruiteQuoteComposite.FruiteQuoteCompositeBuilder()
.setFruitQuoteApplicationException(fruitQuoteApplicationException)
.build();
return withPayload(requireNonNull(outboundFruitQuoteComposite))
.setHeader(MessageHeaders.REPLY_CHANNEL, "applicationErrors")
.build();
}
FruiteQuoteComposite outboundFruitQuoteComposite = new FruiteQuoteComposite.FruiteQuoteCompositeBuilder()
.setFruitQuoteRequestJAXB(fruitQuoteRequestJAXB)
.build();
return withPayload(requireNonNull(outboundFruitQuoteComposite))
.setHeader(MessageHeaders.REPLY_CHANNEL, "requestUUIDEnrichment")
.build();
}
- My 1st question For some reason, the .setHeader invocation isn't working as expected and the message isn't going to the next channel. Is there something I am missing? The result is the same even when I use .setReplyChannelName.
- My 2nd question In case there is a solution to question 1), keeping the overall SI configuration as XML-based, is there an alternate approach to setting customized reply channels? The only option that came to my mind were using a router after every single transformer but this seemed too verbose.
Can you please help?
