DDS11 — (R#119) Need lookup_instance method on reader and writer

There are get_key_value operations in the DataReader and DataWriter to translate from an instance handle to a key. However, in order for a client of the Service to use the per-instance read and take operations of a DataReader, it would be convenient to have an operation to translate in the other direction: from key value(s) to an instance handle.

Proposed Resolution:
Add operations DataReader::lookup_instance and DataWriter::lookup_instance.

Proposed Revised Text:
Append the following rows to the DataWriter Class table in 2.1.2.4.2:
lookup_instance InstanceHandle_t
Instance Data

Add a new section "2.1.2.4.2.23 lookup_instance" with the following contents:
This operation takes as a parameter an instance (to get the key value) and returns a handle that can be used in successive operations that accept an instance handle as an argument.
This operation does not register the instance in question. If the instance has not been previously registered, or if for any other reason the Service is unable to provide an instance handle, the Service will return the special value HANDLE_NIL.

Append the following rows to the DataReader Class table in 2.1.2.5.3:
lookup_instance InstanceHandle_t
Instance Data

Add a new section "2.1.2.5.3.33 lookup_instance" with the following contents:
This operation takes as a parameter an instance (to get the key value) and returns a handle that can be used in successive operations that accept an instance handle as an argument.
If for any reason the Service is unable to provide an instance handle, the Service will return the special value HANDLE_NIL.

No Data Available