Subscriptions

Having created the indication and filter classes, we now need to tie a particular filter to a particular handler by creating an instance of an association descended from CIM_IndicationSubscription. This will cause the WBEM server to inform the provider registered to generate the indications that someone is listening for them. If this is the first such subscription then this may cause the provider to start generating indications when the external events occur.

I list part of the mof for the CIM_IndicationSubscription class in Figure 8.5. This is a straightforward association between a filter and a handler, represented by a CIM_ListenerDestination.

 // ============================================================= // IndicationSubscription // ============================================================= [Association, Version ( "2.7.1000"), Description (     "CIM_IndicationSubscription describes a flow of "    "Indications. The flow is specified by the referenced "    "Filter, and directed to the referenced destination or "    "process in the Handler. Property values of the "    "referenced CIM_IndicationFilter instance and "    "CIM_ListenerDestination instance MAY significantly "    "affect the definition of the subscription. E.g., a "    "subscription associated with a \"Transient\" "    "destination MAY be deleted when the destination "    "terminates or is no longer available.") ] class CIM_IndicationSubscription {       [Key, Description (       "The Filter that defines the criteria and data of the "       "possible Indications of this subscription.") ]    CIM_IndicationFilter REF Filter;       [Key, Description (       "The Handler addressing delivery of the possible "       "Indications of this subscription.") ]    CIM_ListenerDestination REF Handler;    // many properties deleted    }; 

Figure 8.5: Part of CIM_IndicationSubscription