This class is available for the OPUS Blackboard API. The initial OPUS 2.0 release is described here
Constructors:
Trigger( ) | |
~Trigger( ) |
Methods:
poll( ) | apply condition to Blackboard |
str( ) | return Trigger name |
Description
Trigger objects specify the search criteria on a blackboard for generating an event. As such, they contain a blackboard entry that serves as the search condition for polling. Matching entries to the search can have a field modifier applied to them that can be used to prevent re-triggering. A copy of an Event object of the type to be generated after polling finds a match is maintained by the object.
See Also:
Trigger::Trigger - The Trigger constructor.
Synopsis
Trigger::Trigger(Blackboard* bbrd, // I - Blackboard pointer const Entry* e, // I - Trigger condition const string& t, // I - label for Trigger const Field* f, // I - Field modifier const Event* evt, // I - Event to generate const int mx) // I - max. matching Entry's
Description
The constructor creates local copies of all of the calling arguments.
Exceptions Thrown
Trigger::~Trigger - The Trigger destructor.
Synopsis
Trigger::~Trigger()
Description
The destructor deletes private data objects allocated off of the heap.
Exceptions Thrown
Trigger::poll - Poll blackboard for matches to condition.
Synopsis
Event* Trigger::poll()
Description
This method calls the search method of the associated blackboard with the trigger condition. If matching entries are found, the modifier (if defined) is applied to each match, and the entries are replaced on the blackboard. Finally, an Event is generated.
No matching entries to the blackboard search results in the return of a null pointer.
Returns
A pointer to an Event object constructed off the heap if the triggercondition was satisfied; 0 otherwise.
Exceptions Thrown
Trigger::str - Get the trigger name
Synopsis
string Trigger::str() const
Description
This method returns the name of the trigger set at construction.
Returns
string containing the trigger name
Exceptions Thrown
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Last modified: 25 April 2000