A Framework for Constraint-Based Collaborative Web Service Applications and A Travel Application Case Study

Future Web applications will be more collaborative, and will use the standard and ubiquitous Internet protocols. Independently developed applications will have to be integrated seamlessly despite their heterogeneous origins. Heterogeneity stems from programming languages, development environments, operating systems, and host devices. It can be addressed by providing means of composing (or reusing) existing application functionalities in the form of Web services. This works toward the goal of developing new Web applications and processes with limited programming effort. We have developed System on Mobile Devices (SyD) middleware for rapidly developing and deploying collaborative applications over heterogeneous and possibly mobile devices. SyDLink is a key module of SyD; it enables creation of coordination links (Web bonds) between Web services (independently developed applications and application components). SyDLink-enabled entities allow high-level description and enforcement of application constraints among application components. Using such entities, a collaborative application can be created rapidly with limited coding. To illustrate the concepts and implementation of SydLink-enabled collaborative applications, we present a travel reservation system as a case study to show how such an application can be developed and deployed quickly. The travel reservation system is put together by creating SyD coordination links between the independent flight, car, and hotel reservation Web services.