Abstract: An interactive system, such as a webserver, is described of the type wherein responses to a user are associated with states of a state machine, the responses being generated as a result of a transition into a state associated with the response, the system comprising a state machine controller arranged to change states of the state machine according to the processing of user-initiated events. To provide for handling of concurrent events, the state machine controller is arranged, during processing of a current event, to determine whether the current event was initiated at an earlier time than another event and, if so, (i) restore the state machine to a condition consistent with that immediately prior to processing of the current event, and then (ii) carry out a state transition according the other event.

Abstract: A web application is described that is capable of assuming a plurality of states and being arranged to process a received event from among a predeterminable set of events to change from one state to another. A permission record defines a set of permitted or forbidden events and the web application comprises an event filter arranged to consult the permission record on receipt of an event in order to determine whether to permit or not permit the event to be processed. Related methods of access control and computer program products are also described.

Abstract: An interactive system, such as a webserver, is described of the type wherein responses to a user are associated with states of a state machine, the responses being generated as a result of a transition into a state associated with the response, the system comprising a state machine controller arranged to change states of the state machine according to the processing of user-initiated events. To provide for handling of concurrent events, the state machine controller is arranged, during processing of a current event, to determine whether the current event was initiated at an earlier time than another event and, if so, (i) restore the state machine to a condition consistent with that immediately prior to processing of the current event, and then (ii) carry out a state transition according the other event.

Abstract: A web application framework is described for implementing a web server of a type capable of assuming a plurality of states and being arranged to process a received event from among a predeterminable set of events to change from one state to another, with each state having associated with it one or more model objects for providing the server with business logic and/or access to persistent data, the application framework comprising a context object class for creating objects containing data relating to each state, the context object class providing for an entry method for execution upon entry of the state, and an exit method for execution upon exit of the state.

Abstract: A web application is described that is capable of assuming a plurality of states and being arranged to process a received event from among a predeterminable set of events to change from one state to another. A permission record defines a set of permitted or forbidden events and the web application comprises an event filter arranged to consult the permission record on receipt of an event in order to determine whether to permit or not permit the event to be processed. Related methods of access control and computer program products are also described.

Abstract: A web application is described of a type capable of assuming a plurality of nested states and being arranged to process a received event from among a predeterminable set of events to change from one state to another, the web application comprising a state machine in which one or more states correspond to transaction units of work.