How can I get the DDS time with OpenDDS in Java

[yuan-ge]

I'm using OpenDDS with Java17, and now, I want to get the DDS time to compare with the timestamp in SampleInfo, so that I can know the transmission delay from pub to sub.
I have read the doc of opendds, and I just find this:

in OpenDDS Development Guidelines. But I didn't find the corresponding class in DDS library.
Is there any way to solve this problem? Thanks.

[iguessthislldo]

SystemTimePoint is an internal C++ type. You can get the current Time_t using the get_current_time method on your DomainParticipant. It's just Unix epoch time, so you can also get the same exact information from the Java standard library using something like getEpochSecond() and getNano() from Instant.now().

[yuan-ge]

Is this Time_t get by get_current_time the synchronization time of DDS system?

[jrw972]

Time_t is the type used by DDS to represent points in time such as when samples were sent and other time points. It is usually derived from the system clock so it assumes that the clocks of both writer and reader are synchronized.