TARGET:

Java Common Annotations and APIs specification, section "Java API" / {"CallableReference"}

DESCRIPTION:

The getCallbackID() method description doesn't specify the initial state of the returned value and the events that cause this value to change.

Consider the following sequence of events: 1) A ServiceReference is created, either by injection or by ComponentContext.getServiceReference(). 2) getCallbackID() is called on the ServiceReference. 3) A type-safe reference (proxy) is created from the ServiceReference by CallableReference.getService(). 4) getCallbackID() is called on the ServiceReference. 5) A service call is made through the type-safe reference. 6) getCallbackID() is called on the ServiceReference.

It seems reasonably intuitive that call 2) will return null and call 6) will return the system-generated callback ID that was used for the service call. It's less clear what call 4) will return. Does the system-generated callback ID get created and set into the ServiceReference as part of event 3) or as part of event 5)?

The description of the getCallbackID() method should describe a "state model" for how the value returned would change based on other actions.

PROPOSAL:

At point 2) the value returned will be null. At point 4, it will still be null, At point 6), it will be the system-generated callback ID that was used for the service call 5). This information should be stated explicitly in the description of getCallbackID().

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