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DSMCC P

ROTOCOLS

AND

NTERFACES

As revised 2006.05.04

Bionic Buffalo Tech Note #55

Security:

Unrestricted

When a

Stream

object is downloaded to the client from a carousel, the downloaded object is

implemented on the client, but supports only a limited subset of the defined operations. The downloaded
object state consists of references (taps) describing the network address of a broadcast program. No

interactive playback support is provided.

12. Abstract Interfaces

Some interfaces described in DSMCC are abstract and not instantiable. In other words, they can be
inherited by other DSMCC interfaces, but an object with such an interface alone never exists.

DSM::Access

defines attributes which provides size, update time and date, lock status, and a mask of

which user groups have manager, broker, writer, or reader access to an object. Most instantiable DSM
CC interfaces inherit

DSM::Access

DSM::Base

provides two operations:

destroy()

and

close()

, for the destruction of objects and

for the release of references. Most instantiable DSMCC interfaces inherit

DSM::Base

DSM::Composite

allows a set of child objects to be associated with a given (parent) object; the

parent object inherits the

DSM::Composite

interface. A version is associated with each child object.

The interface exists for the convenience of developers, and is not required by any part of the DSMCC

specification.

DSM::Config

is used to implement a form of asynchronous operation call on the object which inherits

the

Config

interface. An attribute

DeferredSync

is used to switch the operation calls between

synchronous and asynchronous mode. In asynchronous mode, calls immediately return a request handle

from the stub, without waiting for the operation to complete. With the

inquire()

operation, the

request handle may be used to check status. With the

wait()

operation, the handle may be used later to

wait for operation completion.

DSM::Event

may be inherited by DSM::Stream. It is by an application to intercept event information

embedded in the content stream. The

subscribe()

operation subscribes to an event, while

unsubscribe()

cancels a subscription. The

notify()

operation blocks, not returning until one of

the subscribed events has been received.

DSM::First

may be inherited by a

DSM::Session

object. It provides two operations:

root()

obtain the

ServiceGateway

reference, and

service()

to obtain a reference to the primary service

object.

DSM::Kind

may be inherited by any instantiable interface. It provides two operations:

has_a()

determine if an object supports a given interface, and

is_a()

to list the interfaces supported by an

object.

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