ITK API and reference implementation scenarios

Each individual scenario is illustrated via a sequence diagram, some explanatory text and some key code snippets. If you prefer, the samples project contains the implementation code to fulfil these scenarios as well as some instructions on how to download, install and run the samples yourself.

In general the example code and sequence diagrams depict how the service client/message originator constructs a message that is fulfilled by/sent to the service provider.

The scenarios are grouped into three general integration patterns (synchronous, simple asynchronous and routed message) as viewed from the initiating application perspective.

The synchronous interaction pattern is the simplest pattern supported by the ITK. The synchronous pattern is applicable to scenarios where there is a user waiting (for instance a user has sent a query) or where there is a business response and the destination service is directly reachable.

The simple asynchronous pattern is suitable for service invocations where the service provider is naturally (currently) asynchronous, or where the processing of the business payload is suitably intensive that a synchronous call might result in infrastructure (such as firewall connection) timeouts or similar resource issues.

The routed message pattern is suitable for messaging where the destination system is not directly reachable and/or where corresponding business responses are triggered via human interaction (for instance the acceptance of a discharge summary by the GP). In the diagram (below) an intermediary ITK router is shown. Note that the pattern is identical from an originator and destination system perspective if there are zero, one or many intermediary ITK routers.