DDS11 — R#180) Clarify which entities appear as instances to built-in readers

The specification does not explicitly state whether clients of the built-in DataReaders should be able to discover other entities that belong to the same participant by those means. In other words, if a DataReader 'A' belongs (indirectly) to a DomainParticipant 'B', will information about A appear when one reads from the subscription built-in reader of B?

We believe that most users will not want to "discover" entities they created themselves; the purpose of the built-in entities is to discover what exists elsewhere on the network. Furthermore, there is currently no way for a client of the built-in reader to distinguish between entities belonging to its own DomainParticipant and those that exist elsewhere on the network.

Proposed Resolution:

Clarify the descriptions of the built-in topics to indicate that data pertaining to entities of the same participant will not be made available there.

A mechanism to determine whether an instance handle (read from a built-in topic or obtained through any other means) represents a particular known entity is generally useful. Add the following operations:
· InstanceHandle_t Entity::get_instance_handle()
· boolean DomainParticipant::contains_entity(InstanceHandle_t a_handle)

Proposed Revised Text:

Add the following sentence to the end of the first paragraph on page 2-129:

A built-in DataReader object obtained from a given participant will not provide data pertaining to other entities created (directly or indirectly) from that participant under the assumption that such objects are already known to the application.

Add the following row to the Entity Class table in section 2.1.2.1.1:

get_instance_handle InstanceHandle_t

Add the description of the new operation as a new section:

2.1.2.1.1.8 get_instance_handle

Get the instance handle that represents the Entity in the built-in topic data, in various statuses, and elsewhere.

Add the following row to the DomainParticipant Class table in section 2.1.2.2.1:
contains_entity boolean
a_handle InstanceHandle_t

Add the description of the new operation as a new section:

2.1.2.2.1.26 contains_entity
This operation checks whether or not the given instance handle represents an entity that was created, directly or indirectly, from the DomainParticipant. The instance handle for an Entity may be obtained from built-in topic data, from various statuses, or from the Entity operation get_instance_handle.

Add the new operations to the IDL PSM in section 2.2.3:

interface Entity

;

interface DomainParticipant : Entity

;

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