Coding your Java agent logic

You override parent class methods to define a Java™ agent that meets your needs.

1. getBoundEntity() to retrieve the entity of interest, and cast the result to the interface that defines the bound entity.

   The bound entity is generated automatically from your model.

   1. If the entity does not exist, create the entity by using the createBoundEntity() method.
   For example:

   Player player = (Player) getBoundEntity();
   if (player == null) {
   player = createBoundEntity();
   } 

2. Use the time stamp from an event or the current system time to set the date and time.
   For example, if the business definitions contained the following entry:

   a player has a last transaction time (date & time).

   You can write the following line of code:

   player.setLastTransactionTime(thisEvent.get$Timestamp());

   The value that is returned by get$Timestamp() is the time when the event is fired. get$Timestamp() is similar to the value of now used in a rule agent.

   The ZonedDateTime class is used to represent all of the time stamps in the system. If you save a time stamp in an entity, or emit an event, you must use the ZonedDateTime class to manipulate the time stamp of the event that is being processed.

3. emit(Event event) to emit a new event to do something.

   Use getConceptFactory to programmatically construct events.

   For example:

   if (player.getBankroll() > 1000) {
      CashBonus cashBonus = getConceptFactory(ConceptFactory.class).createCashBonus(null);
      cashBonus.setAmount(100);
      emit(cashBonus);
   } 

4. Use the Java interfaces get methods to get a value from an event or the bound entity.
   For example:

   PlayerDetails pd = playerDetailsService.getPlayerDetails(player.getPlayerId());
   Status status = Status.valueOf(pd.getAccountStatus());
   player.setStatus(status);

   1. You can also use instanceof tests to cast the event that is handled by the process method to one of the generated interfaces from your model.
5. updateBoundEntity(Entity) to update the bound entity after it is created or modified.

   Call this method when a bound entity is modified so that entity changes are saved to the object grid. You must verify that the bound entity is successfully updated. If more than one agent is bound to an entity, the entity is passed to each agent that reads from or writes to the object grid. Therefore, if the updateBoundEntity method is not called, agents that use the entity might not receive the most current version.

   For example:

   updateBoundEntity(player);

6. Schedule callbacks to the agent by using the schedule method.
   1. Override the process(String, String) method to handle scheduled notifications.
7. Call getGlobalValue(String) to retrieve the value of a global event or entity aggregate.

   For more information, see Defining global aggregates.

8. Call getJobService() to programmatically request updates to the values of global event or entity aggregates.
9. Run geospatial calculations by calling getSpatialService() .
   You must get a geospatial service, a geometry factory from that service, and then instantiate instances of any geospatial type from that factory. All coordinates are by default in the decimal representation of world coordinates in latitude/longitude pairs, unless you define a different coordinate reference system. The following example instantiates a polygon with three points.

   @Override
   public void process(Event event) throws AgentException {
      if(event instanceof Transaction) {
         Transaction transaction = (Transaction)event;
         GeoSpatialService geometryService = GeoSpatialService.getService();
         GeometryFactory geometryFactory = geometryService.getGeometryFactory();
         Polygon poly = geometryFactory.getPolygon(
            geometryFactory.coordsToPoints(new double[][]{
               {1.0, 1.1},
               {1.2, 1.3},
               {1.4, 1.5}
            })
         );
         transaction.setPolygon(poly);
      }
   }