1. A method of scheduling a request for a plurality of Web services comprising the steps of: (a) providing a plurality of service activation rules, each service activation rule specifying a trigger condition and a state condition for causing a watcher to invoke a particular Web service; (b) receiving at least one event indicating a change in a common memory, wherein each event specifies trigger information; (c) comparing the trigger conditions of the service activation rules with the trigger information of the at least one event; (d) adding service activation rules that match the at least one event to a trigger list; (e) comparing the state conditions of service activation rules in the trigger list with a state of the common memory; and (f) selecting the service activation rules of the trigger list that match the state of the common memory, thereby causing the invocation of at least one watcher and corresponding Web service, wherein the state of the common memory is dictated by at least one pattern object.