This ticket is to track adding support for ROS actions to ros2_java.

Some early work related to code generation for actions was done in #66, #76, and #108.
There has also been some work done towards the action client (discussed in #82 (comment)).

I think we can break this task into two parts:

• Action server implementation
  • Access Node clock (Add getClock method to Node interface #139 )
  • Fixes to action code generation (Compile generated action-related services #140 )
• Action client implementation

Additional resources:

• ROS 2 action design
• C++ implementation
• Python implementation