Fawkes API
Fawkes Development Version
|
Thread to translate ROS twist messages to navigator transrot messages. More...
#include "cmdvel_thread.h"
Public Member Functions | |
ROSCmdVelThread () | |
Constructor. | |
virtual void | init () |
Initialize the thread. | |
virtual void | loop () |
Code to execute in the thread. | |
virtual bool | prepare_finalize_user () |
Prepare finalization user implementation. | |
virtual void | finalize () |
Finalize the thread. | |
Protected Member Functions | |
virtual void | run () |
Stub to see name in backtrace for easier debugging. |
Thread to translate ROS twist messages to navigator transrot messages.
ROSCmdVelThread::ROSCmdVelThread | ( | ) |
Constructor.
Definition at line 35 of file cmdvel_thread.cpp.
void ROSCmdVelThread::finalize | ( | ) | [virtual] |
Finalize the thread.
This method is executed just before the thread is canceled and destroyed. It is always preceeded by a call to prepare_finalize(). If this is not the case this is a failure. The condition can be checked with the boolean variable finalize_prepared.
This method is meant to be used in conjunction with aspects and to cover thread inter-dependencies. This routine MUST bring the thread into a safe state such that it may be canceled and destroyed afterwards. If there is any reason that this cannot happen make your prepare_finalize() reports so.
This method is called by the thread manager just before the thread is being cancelled. Here you can do whatever steps are necessary just before the thread is cancelled. Note that you thread is still running and might be in the middle of a loop, so it is not a good place to give up on all resources used. Mind segmentation faults that could happen. Protect the area with a mutex that you lock at the beginning of your loop and free in the end, and that you lock at the beginning of finalize and then never unlock. Also not that the finalization may be canceled afterwards. The next thing that happens is that either the thread is canceled and destroyed or that the finalization is canceled and the thread has to run again.
Finalize is called on a thread just before it is deleted. It is guaranteed to be called on a fully initialized thread (if no exception is thrown in init()) (this guarantee holds in the Fawkes framework).
The default implementation does nothing besides throwing an exception if prepare_finalize() has not been called.
Exception | thrown if prepare_finalize() has not been called. |
Reimplemented from fawkes::Thread.
Definition at line 62 of file cmdvel_thread.cpp.
References fawkes::BlackBoardAspect::blackboard, and fawkes::BlackBoard::close().
void ROSCmdVelThread::init | ( | ) | [virtual] |
Initialize the thread.
This method is meant to be used in conjunction with aspects. Some parts of the initialization may only happen after some aspect of the thread has been initialized. Implement the init method with these actions. It is guaranteed to be called just after all aspects have been initialized and only once in the lifetime of the thread. Throw an exception if any problem occurs and the thread should not run.
Just because your init() routine suceeds and everything looks fine for this thread does not automatically imply that it will run. If it belongs to a group of threads in a ThreadList and any of the other threads fail to initialize then no thread from this group is run and thus this thread will never run. In that situation finalize() is called for this very instance, prepare_finalize() however is not called.
Reimplemented from fawkes::Thread.
Definition at line 41 of file cmdvel_thread.cpp.
References fawkes::ConfigurableAspect::config, fawkes::Configuration::get_string(), fawkes::BlackBoardAspect::blackboard, fawkes::BlackBoard::open_for_reading(), and fawkes::ROSAspect::rosnode.
void ROSCmdVelThread::loop | ( | ) | [virtual] |
Code to execute in the thread.
Implement this method to hold the code you want to be executed continously. If you do not implement this method, the default is that the thread will exit. This is useful if you choose to only implement once().
Reimplemented from fawkes::Thread.
Definition at line 83 of file cmdvel_thread.cpp.
bool ROSCmdVelThread::prepare_finalize_user | ( | ) | [virtual] |
Prepare finalization user implementation.
This method is called by prepare_finalize(). If there can ever be a situation where it is not safe to turn of a thread at some point in time then implement this method to determine these unsafe states.
An example that comes to my mind is our Katana arm. If you turn it off it looses all power and collapses back upon itself. This may damage the arm if it is not in a safe position. In this situation this method would return false to indicate this problem.
It is up to the user to decide if this should be taken for an implied signal to get in such a safe state, if this is possible at all.
This feature should be used rarely as it can have tremendous implications on the performance and experience of the whole software. In any case your implementation should somehow inform the user of the problem that caused the finalization to fail. If you are using aspect use the LoggerAspect and log the reason.
The default implementation always allows finalization.
Reimplemented from fawkes::Thread.
Definition at line 55 of file cmdvel_thread.cpp.
virtual void ROSCmdVelThread::run | ( | ) | [inline, protected, virtual] |
Stub to see name in backtrace for easier debugging.
Reimplemented from fawkes::Thread.
Definition at line 55 of file cmdvel_thread.h.