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.”

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.

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.

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.

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.

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.

The DOF Interface items are properties, methods, events, and exceptions.