spring-integration-samples/intermediate/travel

Travel Sample

This example demonstrates a simple process that could be useful when building travel related applications. It defines two services:

1. Get Weather report based on the ZIP (Postal) code
2. Get Traffic report based on the ZIP (Postal) code

It uses real services provided by third party providers.

• Get Weather report Service is a SOAP Web Service
• Get Traffic report Service is an HTTP Service

This example demonstrates how to configure both:

• HTTP Outbound Gateway - to integrate with HTTP Service
• WS Outbound Gateway - to integrate with WS Service

The diagram below shows the message flow:

	                                                          weatherPreProcessChannel                     weatherChannel                         weatherServiceChannel
	                                                         |------------------------| -> transformer -> |--------------| -> header-enricher -> |---------------------| -> ws:outbound-gateway 
     |-> getWeatherByZip(zip)     routingChannel           /
TravelGateway                --> |--------------| -> h-v-r|
     |-> getTrafficByZip(zip)                             |     trafficChannel
                                                           \ |-----------------| -> http:outbound-gateway     

Two services are exposed via the Gateway. The gateway enriches the headers of the message with the type of request weather or traffic and sends the Message to the routingChannel from which it is retrieved by the HeaderValueRouter (h-v-r) which routes the Message to either weatherPreProcessChannel or trafficChannel based on the value of the REQUEST_TYPE header hat was set by the Gateway.

The WS service requires that the message would be is a certain format. We first need to wrap it into an XML request (done by a transformer), then we need to add a SOAP Header (done by header-enricher). Once Message is properly formatted it is sent to the ws:outbound-gateway, which replies with XML describing real time weather conditions in a particular ZIP code.

The HTTP Service does not require any pre-processing. All we need to do is map the HTTP URI variable {zipCode}. We do it via the element of the http:outbound-gateway.

<uri-variable name="zipCode" expression="payload"/>

Here you see, we are using Spring Expression Language (SpEL) to bind the value of the payload (zipCode) to this variable. To run sample, execute TravelDemo class.