Service Composition Based Software Solution Design: A Case Study in Automobile Supply Chain

Introduction

SaaS (Software as a Service) is gaining a great deal of attractions today. More and more businesses are adopting SaaS for cost-effective software management solutions as well as business structure and process transformations (Koenig, 2006). The accelerating rate of SaaS adoption points clearly to the need for deeper integration with other enterprise applications, as well as other SaaS applications. This is one of the major IT concerns about SaaS viability. One potential solution for this emerging challenge is what Saugatuck calls the “SaaS Integration Platform” (West, 2006).

Some SaaS players are actually moving in the direction to various extents such as Jamcracker, nSite, Opsource, Salesforce.com, etc. The most notable one is the Salesforce’s unique multi-tenant platform, which provides different levels of integration capabilities based on its fundamental Web Services APIs (Salesforce.com). However, one common issue for these integration platforms is their self-centric design pays less attention to the integration with SaaS offerings from different providers. The only capabilities currently provided to connect to other external SaaS offering are Web Service calls. This is far from enough to address the issues including SSO (Single Sign On) and Web Service security caused by different identity management systems, service coordination for ensuring the integrity of business transactions across multiple SaaS offerings, etc.

Traditional middleware providers usually have a more complete view on integration, but the lacking of experiences in SaaS and lacking of industry standards and reference architectures currently available for SaaS integration make it difficult for them to get into the space. One of the challenges they are facing is how to radically simplify their products with significantly reduced footprint if they want to have their platform hosted as a service for a massive number of SMBs (Small and Medium Business).

This paper presents an SOA and Web 2.0 (Wiki) based lightweight approach for SaaS integration. It covers three levels of integration capabilities - presentation, function and data - with end to end security considerations. Most importantly, the approach allows SaaS providers to publish the integration specification of their SaaS offerings in a standard format. SaaS integrator can check out these standard integration elements and compose them together with drag-drop, point and click (DDPC) development tools. This makes the SaaS integration much easier than ever. The adoption of SOA makes the integrated solutions much more flexible and adaptive to changes, thus provides a level of business agility that was impossible to achieve before.

The paper presents a case study showing how we take the approach to compose two SaaS offerings using some of the key technologies we developed so far. Requirements of the case are picked up from supply chain management domain of a real-world automobile manufacturer, whose objective is to improve efficiency and quality of supply chain operation and delivery in its daily business, by importing a new SaaS named SNAP and integrating it with its existing SCM system.

The paper first gives an overview about the real business scenario and customer’s real requirements. Based on the analysis of this scenario, a tentative solution is proposed for the composition of two SaaS offerings. Then the issues surrounding the architecture design are discussed and related technologies and their implementation in the integrated system are introduced. At last, the case study is summarized and future works for improvement is briefed.