An Aspect-Oriented Approach for SaaS Application Customization
  Multi-tenancy is one of the most important concepts for any Software as a Service (SaaS) application. Multi-tenant SaaS application serves a large number of tenants with one single application instance. Complex SaaS application that serves significant number of tenants could have a huge number of customizations with complicated relationships, which increases the customization complexity and reduces the customization understandability. Modeling such customizations, validating each tenant's customization, and adapting SaaS applications on the fly based on each tenant's requirements become very complex tasks. To mitigate these challenges, we propose an aspect-oriented approach that makes use of the Orthogonal Variability Model (OVM) and Metagraphs. The OVM is used to provide the tenants with simple and understandable customization model. A Metagraph-based algorithm has been developed to validate tenants' customizations. On the other hand, the aspect-oriented approach offers a high level of runtime adaptability. 
Ashraf A. Shahin, Areeg Samir, Abdelaziz Khamis
cs.SE