Portable::getType vs PortReader::getReadType vs PortWriter::getWriteType

[drdanz]

Portables have 3 type-related methods:

• PortReader::getReadType()
• PortWriter::getWriteType()
• Portable::getType() (by default returning PortReader::getReadType())

getType() and getReadType() are re-implemented by several Portables (some implementing the first and some the second), and used in several places and I believe they are used for ROS integration.
getWriteType() does not seem to be used or re-implemented anywhere. Why is that? Should we implement this method for our Portables? Perhaps this was added so that there could be some check when connecting two ports?

I think it makes sense (more or less) to have 3 different methods since someone might be defining a PortReader that is not a PortWriter or vice versa. Perhaps Portable should override getReadType() and getWriteType() though, returning the value from getType()? It makes sense for Portable to return the same value for all these 3 methods...