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The Event Subscription Service (ESS) is an event-notification service—for client-application developers—with which to track specific events that may be of interest to users of their client applications. Using the ESS, client-application developers can support:
While executing, the Cisco VPN Solutions Center software publishes events when:
Each event contains identifying information appropriate to the event type. The ESS is supported by the following:
Figure 9-1 shows how the interaction of the various parts of the ESS.
The Event Gateway server uses client-oriented SDKs—supplied by TIBCO to define its interaction with the TIB/Rendezvous software—internally to construct a CORBA wrapper for the TIB/Rendezvous software. The CiscoEventGateway::Callback and CiscoEventGateway::EventGateway interfaces, which are defined in the CiscoEventGateway.idl file, provide the client-development facility by which client applications interact with the Event Gateway server.
The Event Gateway server can support as many client applications as are supported by the Cisco VPN Solutions Center software. Within the scope of each client, the Event Gateway server can support zero, one, or more CiscoEventGateway::Callback objects (instances of the CiscoEventGateway::Callback interface) that can be subscribed by a CiscoEventGateway::EventGateway object to subjects of interest that categorize the events generated during the execution of the Cisco VPN Solutions Center software.
You can create zero, one, or more instances of the CiscoEventGateway::Callback interface—defined in the CiscoEventGateway.idl file—within the scope of each client to suit your coding style or other client-application requirements. Events are delivered to each CiscoEventGateway::Callback object corresponding to its current registration and subject-subscription status, which are set by the operations of the CiscoEventGateway::EventGateway interface.
Specifically, events are delivered to each CiscoEventGateway::Callback object through the in parameter of the CiscoEventGateway::Callback::deliverEvents() operation. In planning your event-handling scheme, devise a standard practice for sorting, storing, or otherwise handling the contents for each event delivered to the CiscoEventGateway::Callback object.
The Cisco VPN Solutions Center Watchdog server supports a single instance of the Event Gateway server, so you can create a maximum of one instance of the CiscoEventGateway::EventGateway interface—defined in the CiscoEventGateway.idl file—to bind to it by name. With the callback-registration operations you can register and deregister Callback objects with the Event Gateway server.
You can also supply programmatic support to reregister all active Callback objects upon restarting the client application. To support the reregistration feature, you must implement a persistent storage scheme to track the unique identifiers for active Callback objects that are returned to the client application upon executing the CiscoEventGateway::EventGateway::registerCallback() operation.
After registering a Callback object, you can programmatically subscribe it to one or more specific subjects used by the Event Gateway server to categorize the events that are reported to it. These subjects represent the categories of events that the VPN Solutions Center software generates while executing. Specifically, subjects indicate the repository name of interest, specific object involved, and the corresponding action.
The TIB/Rendezvous software is a third-party event engine that has C++ and Java SDKs with which to program the interaction between it and client or agent application code. The TIB/Rendezvous software is licensed and bundled for use by the Cisco VPN Solutions Center software. It is installed as part of the installation process for the Cisco VPN Solutions Center software.
The ESS uses the TIB/Rendezvous SDKs to communicate with the TIB/Rendezvous software. VPN Solutions Center support of the TIB/Rendezvous software is limited to programmatic access by way of the Event Gateway server and CiscoEventGateway::Callback objects registered by the client.
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Warning If you must use the TIB/Rendezvous SDKs in your client-application code to directly access the TIB/Rendezvous software, please refer to the TIB/Rendezvous documentation and to TIBCO directly for product support. |
Posted: Fri Sep 22 20:08:09 PDT 2000
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