The ADAPT project pursues to provide open-source middleware support for the creation of adaptive and composable web services. The main hightlights of the project are:
Self-descriptive Basic Services:
In the first place the project will address the problem of defining,
implementing, deploying, and accessing basic web services (BS). The access
point to a BS is through a web server so that it can be treated as an electronic
service (e-service). Part of the research and development efforts of the
project will aim at developing the necessary techniques to enrich BSs with
local properties mentioned earlier, including availability, transactional
interaction and adaptability, for example by using novel replication and
group communication techniques that will allow transparent replication
of the services. Further, a BS will need to provide operations related
to consistency management (e.g., commit, abort, compensate) at the level
of CS, so that global properties of a CS can be
Composite Service definition and enactment of business processes: CSs will be modelled as inter-organisation business processes. Research work will be concerned with analysing and understanding what are the desirable properties of an arbitrarily complex CS built out of BSs and CSs. These properties are the key to building a feasible system. For instance, atomicity in the transactional sense does not make sense at this level because rolling-back the execution might be too expensive or even impossible. Thus, properties like atomicity need to be replaced with other, more encompassing but also more flexible notions of extended transactions. Service composition must also take into account the fact that there could be cases where the constituent service providers might not trust each other, making the task of composing a CS difficult, if not impossible. In such cases, the business process representing a CS will be required to include security related steps for trust establishment. The execution environment must be capable of understanding the global properties and interacting with each individual BSs and CSs in order to enforce these global properties.
Adaptability of BS and CS: Once the BS and the CS levels are supported by a working system, it becomes possible to address the problem of dynamic adaptability. Adaptability of the execution will be achieved by implementing awareness mechanisms that will allow the system to change different aspects of its operation according to circumstances. Self-tuning capacity can be incorporated by using the process structure of the composite services to perform on-line analysis of the current and possible future states of the system. This information can be used for advanced resource reservation, preemptive scheduling, dynamically starting and stopping servers, sending notification and warning to system administrators, and so forth.