This package provides a topic priority management library.
This library allows a module to receive multiple command messages with different origins and order them by priority and lifetime. A topic is kept while its lifetime does not expire. Of the still surviving topics the one with the highest priority is returned.
First add to the module manifest as:
Then include the necessary header:
The next step is to declare the class with the appropriate command message type (in this example we are using the atlascar_base::ThrottleCommand message type).
It is recommended to put a fall back safety message in the queue, this message will be used if no other is available.
atlascar_base::ThrottleCommandPtr safety_command(new atlascar_base::ThrottleCommand); //Set the safety message default values, this messages will never be removed from the list safety_command->lifetime=INFINITY; safety_command->priority=0; safety_command->throttle=0; safety_command->mode=MANUAL; //Push the safety message into the queue command_queue.push_msg(safety_command);
In normal use, the user will push to the queue any command message received
And will obtain the current command to use with:
If the queue is empty the class will return a null boost::shared_ptr.