A BPMN-Based Multi-tenant Customizable SaaS Application: A FARUL3S Case Study

The Ultra-Large Scale Software (ULSS) Systems are characterized by their massive size and complexity in various dimensions. Regulating a ULSS system through constraining the design by using the dominance relations helps to ensure a semantic interoperability between the different domains that are provided by an inter-organizational collaboration. However, a business process model and notation (BPMN)-based multi-tenant customizable SaaS application challenges the existing interoperability approaches due to the business logics introduced by the created BPMN workflows which are not defined during the design stage. In this paper, we propose the System Design Rules Hierarchy version 2 (SDRHv2), a refined version of the SDRH introduced in our previous work. The SDRHv2 aims to cover the tenant-specific BPMN-based customizations through introducing a new level at the bottom of the SDRH hierarchy called Tenant-Specific Design Rules (TSDR). Once the TSDR extends the System Design Rules (SDR) and the Platform Design Rules (PDR) levels of the SDRH in its definition, the tenant-specific data that corresponds to those variables can be easily accessed by the different cooperative organizations working on the same ULSS system. As a case study, we have implemented an administration application, which is a BPMN-based multi-tenant Customizable SaaS application, from scratch based on the Framework for Agile Regulated Ultra-Large-Scale Software systems (FARUL3S) in order to prove the capability of the SDRHv2 to provide semantic interoperability across all levels of the ULSS system hierarchy, and specifically the tenant-specific level.