Event Monitor is an application that can managed the status of a collection of entities as they evolve though an event path.
Event Monitor supports the following:
An event has the following attributes:
Events are always organized into aspects. Examples include: planned, scheduled, actual, revised, estimated
Examples: Load, unload, arrive, depart, lost, damaged, found, destroyed. Pre-defined event types include insert_into_entity_po_set and remove_from_entity_po_set.
The event time.
The event location.
The event entity name.
An entity has a global id and a set of attributes. The attributes are defined by the application. Entities have owners. A OWNER is an individual or organization itself registered as a entity with the system. Each such must have a notification method property (such as an e-mail address).
Entity PO Set
A collection of nodes with a partial ordering. Each node has:
An ideal is a collection of nodes that is closed under either the greater than or less than relation. That is if a node is in an ideal, that all node greater than (or less than) that node are also in the ideal.
Nodes greater than a given node set. If up deals of any node are always linear, then the PO Set is a hierarchy.
Nodes less than a given node set.
The name of the entity to which this node applies.
Always includes one event for each of the predefined event types.
Always includes one trap for each of the predefined event types.
The owner relation is implemented as an entity po set. An entity owns another iff it is properly above the other. Since an entity is always inserted into the owner po set upon creation and deleted therefrom upon destruction, the corresponding insertion and deletion event actions are performed as part of entity constructon and destruction, respectively.
Associated with PO set nodes. Components include:
The event type that springs the trap.
Defines when the trap is sprung. Maybe on event occurrence, on event late, on event early.
When sprung, each trap triggers one or more actions.
Associated with traps. Components include:
May be the nodes in the up deal, the down deal, or both. Execution of an action in a node triggers the execution of actions in related nodes, as defined by the action's targets. Thus a node path is established for each action execution.
The procedure that performs the action. The procedure has access to the environment in which it is executed, including the node path and direction.
Actions may include the sending of notifications to the owners of an entity.