Towards a Distinction between Application State Resources and Data Resources in ROA

In the context of ROA (Resource Oriented Architecture), this paper proposes a distinction between two REST (Representational State Transfer) resources types: The Data Resources (DR) and the Application State Resources (ASR). DR are representations of the application data, at the persistence layer, or remote functions that can be reused in several applications. The ASR represents RESTful application states. An ASR has to follow the HATEOAS(Hypermedia as the Engine of Application State) principle by including links to the next possible application states. The proposed distinction between ASR and DR can be seen as an alternative approach to the distinction between pure RESTful Web services and Web APIs. Furthermore, this paper models the ASR transitions using BPMN (Business Process Model and Notation). The BPMN workflow can properly represent the application states.