1. A method of scheduling pattern-based Web services comprising the steps of: receiving a request for a plurality of Web services; extracting a pattern object from the request and placing the extracted pattern object in a work area, the pattern object specifying a plurality of Web services to be invoked; provisioning one or more termination rules within a termination watcher, wherein the termination watcher removes the pattern object from the work area if it is detected that the pattern object conforms to one or more of the termination rules; providing a plurality of service activation rules accessible by a scheduler, each service activation rule specifying a trigger condition and a state condition for causing a watcher and a corresponding Web service to be activated; receiving in the scheduler at least one event generated dynamically and indicating a change in the work area, wherein each event specifies trigger information; comparing the service activation rules with the trigger information of the at least one event; identifying service activation rules having trigger conditions and state conditions that match the received event and corresponding pattern object; causing watchers specified by the identified service activation rules to execute and thus invoke corresponding Web services; and running the Web services until a termination criterion is detected by the termination watcher.