At the intersection between model-driven service-oriented architecture (SOA) and Web services, IBM Rational Software Architect Version 7.0 and Rational Software Architect for WebSphere Software Version 7.5 play a pivotal role. (Hereafter, "Rational Software Architect" means either in this context.) Either version can be used to model enterprise services, and both versions support transformation of this UML-based service model into Web Service Description Language (WSDL) files, which can then be used to create the Web services. The screenshots provided are for IBM Rational Software Architect Version 7.0. But, the code downloads have working plug-ins for both IBM Rational Software Architect Version 7.0 and Rational Software Architect for WebSphere Software Version 7.5.

Overview of transforming UML models into artifacts for Web services development

IBM Rational Software Architect provides the necessary modeling support to enable model-driven development of SOA solutions. It also supports transformation of UML models into domain-specific software artifacts that can then be used as input for further development and deployment. For Web services-based integration architectures, the UML-based service models can be transformed into WSDL, which developers can then import into various tools and build the service implementation against the service contract defined by the WSDL. At the time of writing this article, Rational Software Architect does not support the following critical aspects of the process:

• Java™ Message Service (JMS) end points in WSDL, which is necessary when SOAP/JMS is the interaction mechanism
• SOAP headers

SOAP over JMS

JMS is becoming a popular transport protocol for Web services. For example, SOAP over JMS is being used to introduce the benefits of a robust and asynchronous messaging backbone to Web services.

Need to specify JMS binding during WSDL generation

Thus, it is very important to be able to generate WSDL files that support JMS end points rather than the default HTTP end points. Yet currently, there is no agreed-upon interoperable standard for specifying SOAP/JMS binding in WSDL, although a W3C working group exists with the mission to produce a recommendation for how SOAP should bind to a transport that supports JMS. Due to this lack of interoperable standard specifications for now, many tools lack enough support for this purpose, especially architecture management tools to generate SOAP/JMS bindings in WSDL. Even so, there is already lot of support for SOAP/JMS in development tools and runtime engines, such as IBM® WebSphere® Integration Developer and WebSphere Message Broker.

Nonetheless, there is sufficient understanding, and there is a commonly used format of the SOAP fragment that is required to specify JMS binding in WSDL. This format is supported by IBM WebSphere Process Server and IBM WebSphere Application Server.

Therefore, it is imperative that the architecture management tools such as Rational Software Architect be extended so that they can generate WSDL files that can work for SOAP/JMS. The code snipped in Listing 1 shows a common way of doing this.

jms:/[queue|topic]?<property>=<value>&<property>=<value>&...

<!-- In that example, the specification of queue or topic corresponds to the JMS address 
destinationStyle attribute. For example: -->
jms:/queue?destination=jms/XYZ&connectionFactory=jms/XYZ&targetService=ServicePort

<wsdl:port name="ABCPort" 
        binding="sqi:ABCSoapJMSBinding">
    <soap:address location="jms:/queue?destination=myQ&connectionFactory=myQCF/" />
</wsdl:port>

The following three tables show the valid properties to use with the <soap:address> tag.

Build a transformation extension plug-in to generate WSDL with SOAP over JMS binding

The purpose of the plug-in is to build a transformation extension that can use a UML service model as the source and generate WSDL that differs from standard DOCUMENT-LITERAL WSDL in these ways:

1. There is no soapAction in soap:operation.
   
   
2. The soap:binding transport is http://schemas.xmlsoap.org/soap/jms.
   
   
3. The soap:address is in the format described in Listing 1.

The XML code shown in Listing 2 contains the transformation extensions and extension rule definitions needed for those conditions.

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>
<extension
        point="com.ibm.xtools.transform.core.transformationExtensions">
        <!-- Custom non-standard JMS binding -->
        <TransformationExtension
        	id="com.ibm.xtools.transform.uml2.wsdl.extension.CUSTOM_JMS_DOCUMENT"
        	name="CUSTOM_JMS_DOCUMENT binding extension Transformation extension"
        	targetTransformation=
			"com.ibm.xtools.transform.uml2.wsdl.internal.Uml2WsdlTransfor.RS"
        	version="1.0.0"
        	enabled="true">
            <Property
                  id="com.ibm.xtools.transform.uml2.wsdl.bindings.CUSTOM_JMS_DOCUMENT"
                  metatype="string"
                  name="com.ibm.xtools.transform.uml2.wsdl.bindings"
                  readonly="true"
                  value="CUSTOM_JMS_DOCUMENT"/> 
<!-- This value (CUSTOM_JMS_DOCUMENT) will 
show up in configuration editor "Binding Options" tab along with all other bindings 
provided as a part of the WSDL transformation -->
        	 <RuleDefinition
           		class="com.ibm.support.rsm.CustomJmsAddressExtensionRule"
           		id="CustomJmsAddressExtensionRule"
           		name="CustomJmsAddressExtensionRule"/>
            <RuleDefinition
                  class="com.ibm.support.rsm.CustomJmsBindingExtensionRule"
                  id="CustomJmsBindingExtensionRule"
                  name="CustomJmsBindingExtensionRule"/>
            <RuleDefinition
                  class="com.ibm.support.rsm.CustomJmsBindingOperationExtensionRule"
                  id="CustomJmsBindingOperationExtensionRule"
                  name="CustomJmsBindingOperationExtensionRule"/>
           	<ExtendTransform
                  targetTransform="AddressExtensionTransform">
              <AddRule 
              	 id="CustomJmsAddressExtensionRule"/>
		    </ExtendTransform>
            <ExtendTransform
                  targetTransform="BindingExtensionTransform">
               <AddRule 
                  id="CustomJmsBindingExtensionRule"/>
            </ExtendTransform>
            <ExtendTransform
                  targetTransform="BindingOperationExtensionTransform">
               <AddRule 
                  id="CustomJmsBindingOperationExtensionRule"/>
            </ExtendTransform>
		</TransformationExtension>    
	</extension>

   <extension
         point="com.ibm.xtools.transform.core.transformationExtensions">
      <TransformationExtension
            id="CustomJMS.transformationExtension"
            name="Transformation Extension"            targetTransformation=
"com.ibm.xtools.transform.uml2.wsdl.internal.Uml2WsdlTransform"
            version="1.0.0">
         <Property
               id="JMSLocationID"
               metatype="String"
               name="JMSLocation"
               readonly="false"
               value="JMSLocationDefaultValue"/>
      </TransformationExtension>
   </extension>
</plugin>

Based on that plugin.xml, you need the Java classes shown in Table 2 to be implemented.

After the plug-in is deployed on a Rational Software Architect installation, when you create a new UML to WSDL transformation configuration, you can see an additional entry for CUSTOM_JMS_DOCUMENT in the WSDL Options drop-down menu (see Figure 1), along with the existing ones (SOAP-DOCUMENT-LITERAL, HTTP-GET, and so forth). You can use the new property to set the JMS binding details for a particular interface. The value you set in the properties pane for JMSLocation gets set into the soap:address location attribute of the WSDL output (see Figure 2).

SOAP headers

Like any good messaging protocol, SOAP defines the concept of a message header, which is an optional part of any SOAP message. If it exists, the header contains information about the message, or about the context in which the message is sent, or whatever the creator of the message thought was a good idea to put there instead of the actual body of the message.

Model SOAP headers as part of the service specification

During modeling of services, there is an obvious need to model the headers along with the input and output payload of the service interface. Therefore, SOAP headers are a critical aspect of SOA modeling. But, as Listing 3 shows, support for modeling SOAP headers as part of the UML service model wasn't included.

<definitions .... >
    <binding .... >
        <operation .... >
           <input>
             <soap:header message="qname" part="nmtoken" use="literal|encoded"
                          encodingStyle="uri-list"? namespace="uri"?>
             <soap:header>*                                
           </input>
           <output>
               <soap:header message="qname" part="nmtoken" use="literal|encoded"
                            encodingStyle="uri-list"? namespace="uri"?>
               <soap:header>*                                
           </output>
        </operation>
    </binding>
</definitions>

Build a transformation extension plug-in to generate WSDL with SOAP headers

The goal of the plug-in is to build a transformation extension to enable modeling of headers and then, based on the model, to generate soap:header in the WSDL.

In the Rational Software Architect UML model, add additional parameters to the UML operation and then, for the parameters that you need to be specified as SOAP headers, add the keyword of "soapHeader."

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>
<extension
        point="com.ibm.xtools.transform.core.transformationExtensions">
                       
        <!-- Custom non-standard JMS binding -->
        <TransformationExtension
        	id="com.ibm.xtools.transform.uml2.wsdl.extension.SOAP_HEADER_DOCUMENT"
        	name="SOAP_HEADER_DOCUMENT binding extension Transformation extension"
        	targetTransformation=
			"com.ibm.xtools.transform.uml2.wsdl.internal.Uml2WsdlTransform.RS"
        	version="1.0.0"
        	enabled="true">
            <Property
                  id="com.ibm.xtools.transform.uml2.wsdl.bindings.SOAP_HEADER_DOCUMENT"
                  metatype="string"
                  name="com.ibm.xtools.transform.uml2.wsdl.bindings"
                  readonly="true"
                  value="SOAP_HEADER_DOCUMENT"/>
<!-- this value (SOAP_HEADER_DOCUMENT) 
will show up in configuration editor "Binding Options" tab along with all other bindings 
provided as a part of the WSDL transformation -->

<RuleDefinition
           		class="com.ibm.support.rsm.SOAPHeaderAddressExtensionRule"
           		id="SOAPHeaderAddressExtensionRule"
           		name="SOAPHeaderAddressExtensionRule"/>
            <RuleDefinition
                  class="com.ibm.support.rsm.SOAPHeaderBindingExtensionRule"
                  id="SOAPHeaderBindingExtensionRule"
                  name="SOAPHeaderBindingExtensionRule"/>
            <RuleDefinition
                  class="com.ibm.support.rsm.SOAPHeaderBindingOperationExtensionRule"
                  id="SOAPHeaderBindingOperationExtensionRule"
                  name="SOAPHeaderBindingOperationExtensionRule"/>
           	<ExtendTransform
                  targetTransform="AddressExtensionTransform">
              <AddRule 
              	 id="SOAPHeaderAddressExtensionRule"/>
		    </ExtendTransform>
            <ExtendTransform
                  targetTransform="BindingExtensionTransform">
               <AddRule 
                  id="SOAPHeaderBindingExtensionRule"/>
            </ExtendTransform>
            <ExtendTransform
                  targetTransform="BindingOperationExtensionTransform">
               <AddRule 
                  id="SOAPHeaderBindingOperationExtensionRule"/>
            </ExtendTransform>
		</TransformationExtension> 
     
	</extension>

</plugin>

Based on the preceding plugin.xml file, you need the following Java classes shown in Table 3 to be implemented.

After the plug-in is deployed in a Rational Software Architect installation, when you create a new UML-to-WSDL transformation configuration, you will see an additional entry of SOAP_HEADER_DOCUMENT in the WSDL Options drop-down menu, along with the existing ones, such as SOAP-DOCUMENT-LITERAL, HTTP-GET.

After selecting the SOAP_HEADER_DOCUMENT value, if you run the transformation, the WSDL generated would look like what Listing 5 shows.

<wsdl:operation name="validatePayment">
  <wsdl:input>
    <soap:header message="wsdl_1:PaymentvalidatePaymentRequest" part="OspreyHeaderIn" 
use="literal"/>
    <soap:body parts="ValidatePaymentRequest" use="literal"/>
  </wsdl:input>
  <wsdl:output>
    <soap:header message="wsdl_1:PaymentvalidatePaymentResponse" part="OspreyHeaderOut" 
use="literal"/>
    <soap:body parts="ValidatePaymentResponse" use="literal"/>
  </wsdl:output>
</wsdl:operation>

Summary

This article explained the growing need to support JMS bindings and SOAP headers as part of the Rational Software Architect UML-to-WSDL transformation. It described one possible way to build transformation extension plug-ins to achieve that goal.

Acknowledgements

Sincere thanks to Dmitry Gorelik (IBM Canada), Murali Pattathe (IBM Canada) and Priyankar Malakar (IBM India) for their help in reviewing this article.

Back to top

Downloads

Information about download methods

Resources

Learn

• All of these sources provide additional helpful information:
  • Transformation to SOA: Part 3. UML to SOA by Dmitry Gorelik (IBM developerWorks, January 2008)
  • How to extend the UML-to-WSDL transformation
  • The SOAP over JMS provider
  • Which style of WSDL should I use? by Russell Butek (developerWorks, May 2005)
  • Charter of the W3C SOAP-JMS Binding Working Group
  • Web services programming tips and tricks: Using SOAP headers with JAX-RPC by Andre Tost (developerWorks, October 2003)
  
  
• Visit the Rational software area on developerWorks for technical resources and best practices for Rational Software Delivery Platform products.
  
  
• Explore Rational computer-based, Web-based, and instructor-led online courses. Hone your skills and learn more about Rational tools with these courses, which range from introductory to advanced. The courses on this catalog are available for purchase through computer-based training or Web-based training. Additionally, some "Getting Started" courses are available free of charge.
  
  
• Subscribe to the Rational Edge newsletter for articles on the concepts behind effective software development.
  
  
• Subscribe to the IBM developerWorks newsletter, a weekly update on the best of developerWorks tutorials, articles, downloads, community activities, webcasts and events.
  
  
• Browse the technology bookstore for books on these and other technical topics.
  
  

Get products and technologies

• Download trial versions of IBM Rational software.
  
  
• Download these IBM product evaluation versions and get your hands on application development tools and middleware products from DB2®, Lotus®, Tivoli®, and WebSphere®.
  
  

Discuss

• Check out developerWorks blogs and get involved in the developerWorks community.
  
  

About the author

Aditya P. Dutta works as an IT Architect at IBM Global Business Services, India. He specializes in conceptualizing and building enterprise integration solutions. He provides consulting and architectural assistance to IBM customers.

Comments (Undergoing maintenance)

Back to top

Trademarks  |  My developerWorks terms and conditions

Table of contents

• Overview of transforming UML models into artifacts for Web services development
• SOAP over JMS
• Build a transformation extension plug-in to generate WSDL with SOAP over JMS binding
• SOAP headers
• Build a transformation extension plug-in to generate WSDL with SOAP headers
• Summary
• Acknowledgements
• Downloads
• Resources
• About the author
• Comments

Next steps from IBM

• Try: Rational Software Architect
• Demo: Model Rational RequisitePro requirements in Rational Software Architect
• Webcast: Harnessing the power of enterprise architecture
• Briefing: Architecture, design, and construction using the IBM Rational Software Delivery Platform
• Buy: Rational Software Architect

My developerWorks community

Dig deeper into Rational on developerWorks

Rate a product. Write a review.

Write a review for Rational products today!

Special offers