First released in version: 3.2 / Last updated in version: 3.6

Object Assertions and Properties

There are a number of object assertions and properties that are supplied with SmartSpace which can be used in Business Rules. These assertions and properties are defaults that appear with particular features, such as Web forms, ACS, Location removal, Location simulation, Stale location detection and Shifts. Depending on the features you have installed, you might not see all of the assertions and properties listed. These assertions and properties are designed to help reduce inaccurate location tagging and define behaviors of an object in simulation.

delete pending flag

One built-in Boolean property of objects that can be set using a button is the “delete pending flag”. Creating a button based on this property is the recommended way to allow certain web site users to manually delete objects from the system. The “delete pending flag” follows the correct sequence of actions by first disassociating any tag from the object, then deleting the object from the data model, so it avoids any race condition where the object could receive a location after it has been removed. If additional clean up actions are required before deleting the object, then another Boolean property should be used along with business rules/integration code to do the clean-up and then set the delete pending flag to finally remove the object.

Setting the "delete pending flag" avoids a potential problem when an object has its location removed but then gets a location update before deletion is complete.

Note: the "delete pending flag" property is only configured after installing the Web forms feature.

ignore tag locations flag

If this flag is set on a tagged object, that object will not get locations from its tag until the flag is cleared. For example, if a cart enters a corridor where there is no tracking, sensors in the surrounding area can see the tag and potentially generate poor locations. To prevent these poor locations placing the cart in the wrong place we can set an assertion point at the corridor entrance exit. When the cart is associated with an assertion point, a Business Rule can be triggered to set the flag on (at then entrance) and off (at the exit). The assertions can also place the cart in the corridor. The location will be set for the object, but it will not be precise due to absence of tracking.

Note: the "ignore tag locations flag" property is available if ACS is installed.

remove location pending flag

When this flag is asserted for an object, the object’s location will be removed, and then assertion will be retracted. Any process action that must be executed after the object has been removed can be safely executed when the assertion has been retracted. If the object is still getting located by some other means, such as via driven objects, or an associated tag, then the object might be located again (possibly immediately).

The "remove location pending flag" is reset to false when the object's location is removed. By watching for the transition from true to false, a Business Rule can be triggered that executes some appropriate process action. Note: the object could be located again if the object is driven by a tag or other driving object.

Note: the "remove location pending flag" assertion is available in SmartSpace Core via the Location removalfeature.

remove tag pending flag

Setting this flag on a tagged object causes the tag to be disassociated from the object. Once the disassociation is completed, the flag is reset.

simulation behaviour

A named simulation behavior has a set of service parameters that define how objects behave in simulation. Behaviors are applied to objects using a simple property.

Note: the "simulation behaviour" property is only configured after installing the Location Simulation feature.

simulation target

When there is a simulation target, the object moves to it. If the target doesn’t have a location, the simulator won’t move the object. There are two kinds of target: path points, and any other type of object.

Note: the "simulation target" property is only configured after installing the Location Simulation feature.

stale flag

The stale flag will be set to true for any object currently detected as stale, and will be removed when the object tag is sighted again.

The object becomes stale when, after a specified timeout, an object stops getting location updates from it associated tag and its location is no longer being refreshed. The flag can be used by Business Rules to implement further behavior. For example, a rule might change the representation of the object or remove its location altogether.

The timeout value can be set per type, or even per object, by setting the Stale location timeout parameter in SERVICE PARAMETERS. Automatic removal of the object after stale timeout can also be configured in SERVICE PARAMETERS.

Note: the "stale flag" assertion is available after the Stale location detection feature has been installed.

the shift of <Object> is active

If “report shift activity” is set to true for some object with a shift assigned to it, then when that shift is active the assertion “the shift of <Object> is active” will be made (and when the shift is inactive the assertion will be retracted). You can set or unset the ‘shift is active’ assertion for all objects of a particular type by using the global mechanism in SERVICE PARAMETERS to set default values for all members of the chosen type.

Note: "the shift of <Object> is active" is available after installing the Shifts feature.