DDSPSMC — Expected use of AnyDataReader::get and its implication on AnyDataReader's template constructor

AnyDataReader::get is a member template function, which requires passing a type to retrieve a typed data-reader. For example,

AnyDataReader adr;
DataReader<RadarTrack> dr = adr.get<RadarTrack>();

It is better to pass the topic type instead of the data-reader type. For example,

AnyDataReader adr;
DataReader<RadarTrack> dr = adr.get<dds::sub::DataReader<RadarTrack> >();

The first version is less error prone.

Construction of AnyDataReader, however, does not look consistent with this use. Currently, the template constructor of the AnyDataReader accepts a data-reader as a type parameter (not just the topic type).

Also, it is not consistent with AnyDataWriter constructor, which takes topic type as a type parameter.

Resolution: Use the style of AnyDataWriter in AnyDataReader, AnyTopic, and AnyTopicDescription. I.e., Use the topic type as a type parameter for constructor and get() member function.

The AnyDataWriter in AnyDataReader, AnyTopic, and AnyTopicDescription now use consistently the topic type as a type parameter for constructor and get() member function. Free function get() have also been added to avoid exotic C++ syntax under some circumstances.