Table 1 Core Recommendations of SADI

1

SADI Web services are stateless and atomic.

2

SADI service endpoints respond to HTTP GET by returning the interface definition of the service.

3

Service interfaces (i.e., inputs and outputs) are defined in terms of OWL-DL classes; the property restrictions on these OWL classes define what specific data elements are required by the service and what data will be provided by the service, respectively.

4

SADI services consume and produce data in RDF format.

5

SADI services are invoked through plain HTTP POST of RDF data to the service endpoint.

6

Input RDF data - data that is compliant with (i.e. classifies into) the input OWL Class definition - is "decorated" or "annotated" by the service provider to include new properties until it fulfills the Class definition of the service's output OWL Class. Importantly, in so doing, the URI of the input OWL Class Instance is preserved and becomes the URI of the output OWL Class Instance.