Rational Developer for System z

Transforming an existing CICS application

This section describes the role of the service flow project tools in transforming an existing CICS® application into a Web service.

Figure 1 shows how the service flow project tools can be used to import information from existing applications and to develop subcomponents that are joined together in a service flow. From the service flow, runtime code can be generated for the CICS Service Flow Runtime or the Host Application Transformation Services (HATS).

Figure 1. Service flow project tools
Drawing of components that comprise the service flow project tools.

Services, service-oriented architecture, and the service flow project tools

To understand the usage model for the service flow project tools, you need to understand the concepts of service and a service-oriented architecture (SOA).

It its most basic form, a service is a business function of an application.

A service-oriented architecture (SOA) makes the business function of a particular application available to other applications for invocation and for use in its business model.

The goal of SOA is new interoperability between applications to meet new business demands. For example, you could share services with business partners or make a business function, such as a funds inquiry, available to your customers directly via the Internet.

In the end, a service-oriented architecture represents a collection of services that communicate with each other.

An SOA always involves two participants as follows:
  • A service provider

    The service provider is the company or organization that makes a service available to customers, partners, or suppliers.

  • A service requester

    This SOA participant is a software program that includes its own representation of the service interface. The program is sometimes referred to as a client application or a service consumer, while the representation is sometimes referred to as a service interface proxy.

The service flow project tools provide an environment for transforming existing applications by encapsulating them as reusable integrated business services; it transforms the programmatic interface definition of existing older applications (such as critical applications running on CICS or IMS™) to a different type of interface that is suitable for service-oriented architecture.

The objective of the transformation process enabled by the service flow project tools is to:
  • Encapsulate business functions within mission-critical applications, and make them integrative to a service-oriented architecture.
  • Transform what may have existed as multiple business (application) functions into one newly composed service, so that a single invocation of this service can perform what was previously multiple separate business functions.

Embarking on an application transformation project

Consider application transformation as a component of a larger solution-based effort to transform the enterprise.

Enterprise transformation involves aligning the business needs of an enterprise to the IT actions required to meet those needs.

As previously stated in this help topic, a pressing business need for many corporations today is to leverage the strengths and capabilities that exist in critical back-end applications so that these applications can be part of an on-demand environment.

The phases that participants in an application transformation project undergo include the following:
  • Discovery
  • Development
The following activities apply to the discovery phase of an application transformation project:
  • Analyzing the current business climate that drives the enterprise to make changes to existing processes and IT systems.
  • Evaluating how existing applications and their interfaces work currently to service the business, with the goal of identifying unnecessary manual intervention and pain points.
  • Understanding in detail the applications and systems to be transformed.

As part of the discovery phase of an application transformation project, participants formulate a plan for transforming and re-purposing existing applications to meet the needs of on-demand business.

The discovery phase requires an enterprise to take stock of their current business processes and IT assets for the purpose of identifying those existing applications that they can leverage and transform. What may result from such an analysis are fresh ideas for improving business processes, setting the stage for the application transformation development phase.

The development phase of an application transformation project can involve using the service flow project tools in different approaches.

The service flow project tools supports a bottom-up and a meet-in-the-middle approach to service development.

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