The emerging paradigm of web services provides the basis for the interaction and coordination
of business processes that are distributed among different organizations, which
can exchange services and can cooperate to provide better services, e.g., to third parties
organizations or to individuals. One of the big challenges for the taking up of web
services is the provision of computer automated support to the composition of service
oriented distributed processes, in order to decrease efforts, time, and costs in their development,
integration, and maintenance. The ability to automatically plan the composition
of web services, and to monitor their execution is therefore an essential step toward the
real usage of web services.
BPEL4WS(Business Process Execution Language forWeb Services) [1] is an emerging
standard for the specification and execution of service oriented business processes.
BPEL4WS has been designed with two functions in mind. On the one hand, executable
BPEL4WS programs allow the specification and execution of the processes internal
to an organization (internal processes in the following). On the other hand, abstract
BPEL4WS specifications can be used to specify and publish the protocol that external
agents have to follow to interact with a web service (external protocols in the following).
Therefore, BPEL4WS offers the natural starting point for web service composition.
In this paper, we devise a planning technique for the automated composition and automated
monitoring of web services. Automated composition allows providing services