FAQ – DOF Object Model
What is an Object Identifier?
Every DOF Object has an identifier known as the Object ID (OID). These OIDs must be
globally unique, and OIDs used in the DOF Object Model must also be unique as well as stable.
What is an Interface Identifier?
Each DOF Interface has a unique Interface Identifier (IID). Once a DOF Interface is published, the IID, along with the interface’s defined functionality, remains fixed. Once the interface has been published, it is also said to be “registered.”
What is a DOF Interface?
A DOF Interface defines the items of functionality a DOF Object must provide. These items of functionality are properties, methods, events, and exceptions. Each interface has a unique identifier or IID.
What is an Interface Property?
An Interface Property is similar to a field in a Java class. It defines one specific type of information about the provider. Properties allow for reading, writing, and subscribing to data related to the current object state. Each property has a property type and defines whether it is readable, writable, or both.
What is an Interface Method?
An Interface Method is a function that the requestor can call remotely through an “invoke” operation and that the provider executes in a prescribed fashion (as defined by the interface). The definition of a method also includes the method’s input and output types.
What is an Interface Event?
An Interface Event is a circumstance that triggers a response; it is also an Interface “item.” Requestors can use “register” operations to be notified when the circumstances have occurred on the provider. Events may have output parameters.
What is an Interface Exception?
An Exception is an error condition that interrupts the normal flow of an operation, or, in the case of a DOF interface, it is a logical exception case involving the interface items, which are its properties, methods, and events. Exceptions defined in an interface are called provider exceptions in the API.
What are the DOF Interface Items?
The DOF Interface items are properties, methods, events, and exceptions.