Binding Activator

A binding activator is a special reference that points to a server context variable, a server context event, or a field of a server context variable. A change of the above variable or an occurrence of the above event trigger this binding's processing.

When a binding activator is not specified, references from the binding expression work as activators. In this case, avoid using binding targets in binding expressions. Because the result of a binding expression is written to the binding target, this can cause an eternal loop of updates.

Here is a list of supported activator syntax variations:

context:variable

This activator will trigger a binding once the variable of the server context named context is changed.

Example: users.admin.devices.dev1:voltage This activator will run upon the change of the voltage property in the server-side users.admin.devices.dev1 context.

Only variables whose changes produce Updated events will cause a binding to be activated. This always happens for most variables. This is configurable for other variables, for example device setting variables generate updated events only their History Mode setting assumes that. Finally, variables that generate their values upon read requests are never producing Updated events and cannot trigger a binding.

context:event@

This activator will trigger a binding once event named event occurs in server context named context.

Example: users.admin.devices.access_control_terminal:cardRead@ This activator will run upon the occurrence of the cardRead@ event in the users.admin.devices.access_control_terminal context.

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