Fuse ESB - Using the Apache CXF Binding Component

Chapter 9. Consumer Endpoints

A consumer endpoint listens for requests from external endpoints and delivers responses back to the requesting endpoint. It is configured using a single XML element that specifies the WSDL document defining the endpoint.

Overview

Consumer endpoints play the role of consumer from the vantage point of other endpoints running inside of the ESB. However, from outside of the ESB a consumer endpoint plays the role of a service provider. As shown in Figure 9.1, consumer endpoints listen from incoming requests from external endpoints. When it receives a request, the consumer passes it off to the NMR fro delivery to endpoint that will process the request. If a response is generated, the consumer endpoint delivers the response back to the external endpoint.

Figure 9.1. Consumer Endpoint

	Important
	Because consumer endpoint's behave like service providers to external endpoints, you configure the runtime behavior of the transport using the provider-specific WSDL entries.

Procedure

To configure a consumer endpoint do the following:

Add a consumer element to your xbean.xml file.
Add a wsdl attribute to the consumer element.
See Specifying the WSDL.
If your WSDL defines more than one service, you will need to specify a value for the service attribute.
See Specifying the endpoint details.
If the service you choose defines more than one endpoint, you will need to specify a value for the endpoint attribute.
See Specifying the endpoint details.
Specify the details for the target of the requests received by the endpoint.
See Specifying the target endpoint.
If your endpoint is going to be receiving binary attachments set its mtomEnabled attribute to true.
See Using MTOM to Process Binary Content.
If your endpoint does not need to process the JBI wrapper set its useJbiWrapper attribute to false.
See Working with the JBI Wrapper.
If you are using any of the advanced features, such as WS-Addressing or WS-Policy, specify a value for the busCfg attribute.
See Part III.

The wsdl attribute is the only required attribute to configure a consumer endpoint. It specifies the location of the WSDL document that defines the endpoint being exposed. The path used is relative to the top-level of the exploded service unit.

	Tip
	If the WSDL document defines a single service with a single endpoint, then you do not require any additional information to expose a consumer endpoint.

Example 9.1 shows the minimal configuration for a consumer endpoint.

Example 9.1. Minimal Consumer Endpoint Configuration

<beans xmlns:cxfbc="http://servicemix.apache.org/cxfbc/1.0"
       ... >
  ...
  <cxfbc:consumer wsdl="/wsdl/widget.wsdl" />

  ...
</beans>

For information on creating a WSDL document see Part I: Defining an Endpoint in WSDL.

Specifying the endpoint details

If the endpoint's WSDL document defines a single service with a single endpoint, the ESB can easily determine which endpoint to use. It will use the values from the WSDL document to specify the service name, endpoint name and interface name for the instantiated endpoint.

However, if the endpoint's WSDL document defines multiple services or if it defines multiple endpoints for a service, you will need to provide the consumer endpoint with additional information so that it can determine the proper definition to use. What information you need to provide depends on the complexity of the WSDL document. You may need to supply values for both the service name and the endpoint name, or you may only have to supply one of these values.

If the WSDL document contains more than one service element you will need to specify a value for the consumer's service attribute. The value of the consumer's service attribute is the QName of the WSDL service element that defines the desired service in the WSDL document. For example, if you wanted your endpoint to use the WidgetSalesService in the WSDL shown in Example 9.2 you would use the configuration shown in Example 9.3.

Example 9.2. WSDL with Two Services

<definitions ...
             xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
             targetNamespace="http://demos.widgetVendor.com" ...>
  ...
  <service name="WidgetSalesService">
    <port binding="WidgetSalesBinding" name="WidgetSalesPort">
      <soap:address location="http://widget.sales.com/index.xml">
    </port>
  </service>

  <service name="WidgetInventoryService">
    <port binding="WidgetInventoryBinding" name="WidgetInventoryPort">
      <soap:address location="http://widget.inventory.com/index.xml">
    </port>
  </service>
  ...
<definitions>

Example 9.3. Consumer Endpoint with a Defined Service Name

<beans xmlns:cxfbc="http://servicemix.apache.org/cxfbc/1.0"
       xmlns:widgets="http://demos.widgetVendor.com"
       ... >
  ...
  <cxfbc:consumer wsdl="/wsdl/widget.wsdl"
                  service="widgets:WidgetSalesService" />

  ...
</beans>

If the WSDL document's service definition contains more than one endpoint, then you will need to provide a value for the consumer's endpoint attribute. The value of the endpoint attribute corresponds to the value of the WSDL port element's name attribute. For example, if you wanted your endpoint to use the WidgetEasternSalesPort in the WSDL shown in Example 9.4 you would use the configuration shown in Example 9.5.

Example 9.4. Service with Two Endpoints

<definitions ...
             xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
             targetNamespace="http://demos.widgetVendor.com" ...>
  ...
  <service name="WidgetSalesService">
    <port binding="WidgetSalesBinding" name="WidgetWesternSalesPort">
      <soap:address location="http://widget.sales.com/index.xml">
    </port>
    <port binding="WidgetSalesBinding" name="WidgetEasternSalesPort">
      <jms:address jndiConnectionFactoryName="ConnectionFactory"
                   jndiDestinationName="dynamicQueues/test.Celtix.jmstransport" >
        <jms:JMSNamingProperty name="java.naming.factory.initial"
                               value="org.activemq.jndi.ActiveMQInitialContextFactory" />
        <jms:JMSNamingProperty name="java.naming.provider.url"
                               value="tcp://localhost:61616" />
      </jms:address>
    </port>
  </service>
  ...
<definitions>

Example 9.5. Consumer Endpoint with a Defined Endpoint Name

<beans xmlns:cxfbc="http://servicemix.apache.org/cxfbc/1.0"
       xmlns:widgets="http://demos.widgetVendor.com"
       ... >
  ...
  <cxfbc:consumer wsdl="/wsdl/widget.wsdl"
                  endpoint="WidgetEasternSalesService" />
  ...
</beans>

Specifying the target endpoint

The consumer endpoint will determine the target endpoint in the following manner:

If you explicitly specify an endpoint using both the targetService attribute and the targetEndpoint attribute, the ESB will use that endpoint.
If you only specify a value for the targetService attribute, the ESB will attempt to find an appropriate endpoint on the specified service.
If you specify an the name of an interface that can accept the message using the targetInterface attribute, the ESB will attempt to locate an endpoint that implements the specified interface and direct the messages to it.
If you do not use any of the target attributes, the ESB will use the values used in configuring the endpoint's service name and endpoint name to determine the target endpoint.

Example 9.6 shows the configuration for a consumer endpoint that specifies the target endpoint to use.

Example 9.6. Consumer Endpoint Configuration Specifying a Target Endpoint

<beans xmlns:cxfbc="http://servicemix.apache.org/cxfbc/1.0"
       xmlns:widgets="http://demos.widgetVendor.com"
       ... >
  ...
  <cxfbc:consumer wsdl="/wsdl/widget.wsdl"
                  targetEndpoint="WidgetSalesTargetPort"
                  targetService="widgets:WidgetSalesTargetService" />

  ...
</beans>

	Important
	If you specify values for more than one of the target attributes, the consumer endpoint will use the most specific information.

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