Creating an XML-based service

XML-based services are web service provider or requester applications that use XML to interface with other applications and use a binding to transform the data. XML-based services are available to CICS® applications that use the INVOKE SERVICE API command or to business services that are on an external network.

About this task

You can either create web services using the web services support in CICS or you can use IBM® Developer for z/OS. If you use IBM Developer for z/OS , you can also create an SCA component from your web service. The advantages to creating a component from a web service are as follows:
  • You can more easily reuse existing components to rapidly develop new composite applications using IBM Developer for z/OS.
  • You can use SCDL to describe the web service, moving the configuration information out of the application and into metadata that is easier to change without having to change the application. For example, if you want to run a web service under different transaction and user IDs, you can change the SCDL without having to regenerate the Web service binding file.
In SCA, the application program that you want to expose as a web service is the implementation of the business logic. The application program is defined in the <Implementation> element of a component. The component service describes the interface to the application program in WSDL. A component has one interface, which can contain a number of operations and bindings.

Procedure

  1. Create a composite using IBM Developer for z/OS.
    1. Specify the application program name as the component implementation.
    2. If you want the service to be available externally to CICS , add the web service binding to the appropriate service or reference. If you want the service to be available to CICS applications only, add the CICS binding to the appropriate service or reference and select the mapped mapping mode in the tooling.
      The tooling describes the binding in the SCDL. The SCDL also includes the data mappings that transform the XML to the appropriate high-level language.
    3. Define imports on the composite reference.
      Imports define the dependencies of the composite that must be satisfied in the CICS region.
    A box represents the composite. Inside the composite is another box that represents the component. A small arrow enters the component from the left to represent the component service. Another small arrow leaves the component from the right to represent the component reference. A large arrow enters the composite from the left to represent the composite service; it has text to indicate it is an Operation with a web service binding and a wsbind file. A large arrow leaves the composite from the right to represent the composite reference; it has text to indicate it has Imports with a web service binding.

    For details about the recommended ways to create and deploy composites in CICS , see Best practices for creating and deploying composites.

  2. Deploy the composite to CICS as a bundle.
    IBM Developer for z/OS generates the bundle manifest and packages the SCDL and other artifacts for you. The manifest describes all the resources and metadata that CICS requires to successfully install a BUNDLE resource; the BUNDLE resource represents the composite in the CICS region. The manifest defines the composite as an SCACOMPOSITE resource type and references the location of the SCDL using a relative path.
  3. Create and install the BUNDLE resource.
    You can optionally set an SCA domain on the BUNDLE resource definition. An SCA domain typically represents a set of services that provide an area of business function. You can install the same bundle using different SCA domains, because CICS identifies the service by combining the SCA domain and the name of the service. For details and examples of how to add an SCA domain, see Scoping of bundles.

    You must ensure that all prerequisites of the bundle are available in the CICS region for the BUNDLE resource to install successfully.

    When the BUNDLE resource installs successfully, CICS creates the WEBSERVICE and URIMAP resources for you using the information from the manifest and SCDL. CICS also checks that the resources defined in the Imports section of the Reference are present in the CICS region. The Imports define the prerequisites for the application.

Results

Your web service is successfully installed in CICS.

What to do next

You can test and validate that the web service works as expected. You can view the BUNDLE resource and its contents using the IBM CICS Explorer®. You can also enable and disable the BUNDLE resource to manage all the resources together.