Required use of LIM in the specification of a CSPA Service

6. The LIM is used in the specification of the service. At this stage of design, the service will already have an approved Statistical Service Definition and the service will have been defined in terms of GSIM and the business process flow.

7. For a CSPA service to be considered compliant with the architecture and approved for inclusion in the CSPA Statistical Service Catalogue, it is necessary for the Service designer to explain what the expected interface is. The CSPA Service Specification template requires the data and the process logic and methods to be modelled in LIM.

8. To do this, the Service designer must identify the relevant LIM objects for the service interface. There are some objects that are likely to always be needed (for example process design, data structures). For each service, some lower level details may be required to determine the particular structure of some of the objects identified from LIM (for example the detailed structure of an identified Code List). The service design should identify the specific behaviours of the interface (i.e. would you return a dataset, or a reference to a dataset.) Knowing the architectural patterns to be used and the communication platform may affect which LIM objects are used in the interface.

9. Service Designers can use the Process Package to describe the methodology to be implemented by the Service Builder. There are a number of objects within LIM that are used to describe processes. These objects range from those used to design the Business Process, including the methods and rules used to define the actions encompassed in the process, through to the objects needed to encapsulate the execution-time processing, identifying the inputs used and the outputs produced at each step.

10. For a CSPA Service, these objects are useful tools to enable the complete description of the Service, the actions the Service will undertake and the inputs and outputs needed by the Service to complete these actions. These are documented in the Service Specification.

11. The distinction between the design-time and execution-time process objects indicates a focal point for the Service Designers and Service Builders. While this split isn't mutually exclusive between the two roles, generally speaking a Service Designer could develop a service using the LIM objects for describing a process, while the Service Builder would focus on the execution-time objects.

12. For example, in the Service Specification document used to describe the CSPA Service, the Process Step objects would be used to encapsulate the information about what the Service will do. For the Service Builder, the Process Inputs and Outputs identify what information is to be passed across the service boundaries for the service to perform its function (i.e. the service interface).

13. The service team will need to validate their proposal with the CSPA Implementation Group. In the case where the LIM does not include sufficient objects or attributes, this group can develop the model further to meet the needs of services. Once approved the Service Builder will take this specification and implement it based on the standard(s) that will be used.

Other ways to use LIM

14. Service Builders can use LIM to describe any (machine actionable) orchestration that is encapsulated by the Service. This will help others to understand the data models and process logic in the service (so they can use it) and reuse existing implementations of LIM and their physical representations. They can record these LIM/Process diagrams as appropriate.

15. Assemblers need to know the LIM objects so they can understand whether they can implement the service. They also need to understand the interface, so that they can determine if the service will be able to be integrated.