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BBLoggerThread Class Reference

BlackBoard logger thread. More...

#include "log_thread.h"

Inheritance diagram for BBLoggerThread:

List of all members.

Public Member Functions

 BBLoggerThread (const char *iface_uid, const char *logdir, bool buffering, bool flushing, const char *scenario, fawkes::Time *start_time)
 Constructor.
virtual ~BBLoggerThread ()
 Destructor.
const char * get_filename () const
 Get filename.
void set_threadlist (fawkes::ThreadList &thread_list)
 Set threadlist and master status.
void set_enabled (bool enabled)
 Enable or disable logging.
virtual void init ()
 Initialize the thread.
virtual void finalize ()
 Finalize the thread.
virtual void loop ()
 Code to execute in the thread.
virtual bool bb_interface_message_received (fawkes::Interface *interface, fawkes::Message *message) throw ()
 BlackBoard message received notification.
virtual void bb_interface_data_changed (fawkes::Interface *interface) throw ()
 BlackBoard data changed notification.
virtual void bb_interface_writer_added (fawkes::Interface *interface, unsigned int instance_serial) throw ()
 A writing instance has been opened for a watched interface.
virtual void bb_interface_writer_removed (fawkes::Interface *interface, unsigned int instance_serial) throw ()
 A writing instance has been closed for a watched interface.

Protected Member Functions

virtual void run ()
 Stub to see name in backtrace for easier debugging.

Detailed Description

BlackBoard logger thread.

One instance of this thread handles logging of one specific interface. The plugin will spawn as many threads as there are interfaces to log. This allows for maximum concurrency of the writers and avoids a serialization bottle neck. The log thread can operate in buffering mode. If this mode is disabled, the data is written to the file within the blackboard data changed event, and thus the writing operation can slow down the overall system, but memory requirements are low. This is useful if a lot of data is written or if the storage device is slow. If the mode is enabled, during the event the BB data will be copied into another memory segment and the thread will be woken up. Once the thread is running it stores all of the BB data segments bufferd up to then. The interface listener listens for events for a particular interface and then writes the changes to the file.

Author:
Tim Niemueller

Definition at line 46 of file log_thread.h.


Constructor & Destructor Documentation

BBLoggerThread::BBLoggerThread ( const char *  iface_uid,
const char *  logdir,
bool  buffering,
bool  flushing,
const char *  scenario,
fawkes::Time start_time 
)

Constructor.

Parameters:
iface_uidinterface UID which to log
logdirdirectory to store config files, must exist
bufferingenable log buffering?
flushingtrue to flush after each written chunk
scenarioID of the log scenario
start_timetime to use as start time for the log

Definition at line 75 of file log_thread.cpp.

References fawkes::Time::get_timeval(), fawkes::Thread::set_coalesce_wakeups(), and fawkes::Thread::set_name().

BBLoggerThread::~BBLoggerThread ( ) [virtual]

Destructor.

Definition at line 114 of file log_thread.cpp.


Member Function Documentation

void BBLoggerThread::bb_interface_data_changed ( fawkes::Interface interface) throw () [virtual]

BlackBoard data changed notification.

This is called whenever the data in an interface that you registered for is modified. This happens if a writer calls the Interface::write() method.

Parameters:
interfaceinterface instance that you supplied to bbil_add_data_interface()

Reimplemented from fawkes::BlackBoardInterfaceListener.

Definition at line 380 of file log_thread.cpp.

bool BBLoggerThread::bb_interface_message_received ( fawkes::Interface interface,
fawkes::Message message 
) throw () [virtual]

BlackBoard message received notification.

This is called whenever a message is received for this interface. This method is only called for writing instances of an interface, never on reading instances. If you have processed the message already, you can order that the message is not enqueued by returning false. Returning true will enqueue the message as usual. You should only do very (very!) quick tasks directly in this method, as it is out of the regular thread context and can harm performance of other plugins and the system as a whole. Note that if you decide to return false the message is not referenced. If you want to keep it longer you have to ref() it by yourself. An example where this would really make sense is a "STOP" message for the motor, which needs to be processed ASAP and maybe even waiting a couple of miliseconds for the next cycle is not acceptable.

Parameters:
interfaceinterface instance that you supplied to bbil_add_message_interface()
messagethe message that was sent
Returns:
true to get the message enqueued afterwards as usual, false to prevent queuing of the message.

Reimplemented from fawkes::BlackBoardInterfaceListener.

Definition at line 351 of file log_thread.cpp.

References set_enabled().

void BBLoggerThread::bb_interface_writer_added ( fawkes::Interface interface,
unsigned int  instance_serial 
) throw () [virtual]

A writing instance has been opened for a watched interface.

This is called whenever a writing instance of the interface you are watching is opened.

Parameters:
interfaceinterface instance that you supplied to bbil_add_writer_interface()
instance_serialthe instance serial of the writing instance that has just been added.

Reimplemented from fawkes::BlackBoardInterfaceListener.

Definition at line 407 of file log_thread.cpp.

void BBLoggerThread::bb_interface_writer_removed ( fawkes::Interface interface,
unsigned int  instance_serial 
) throw () [virtual]

A writing instance has been closed for a watched interface.

This is called whenever a writing instance of an interface you are watching is closed.

Parameters:
interfaceinterface instance that you supplied to bbil_add_writer_interface()
instance_serialthe instance serial of the writing instance that has just been removed.

Reimplemented from fawkes::BlackBoardInterfaceListener.

Definition at line 414 of file log_thread.cpp.

void BBLoggerThread::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.

Exceptions:
Exceptionthrown if prepare_finalize() has not been called.
See also:
prepare_finalize()
cancel_finalize()

Reimplemented from fawkes::Thread.

Definition at line 197 of file log_thread.cpp.

References fawkes::BlackBoardAspect::blackboard, fawkes::BlackBoard::close(), and fawkes::BlackBoard::unregister_listener().

const char * BBLoggerThread::get_filename ( ) const

Get filename.

Returns:
file name, valid after object instantiated, but before init() does not mean that the file has been or can actually be opened

Definition at line 222 of file log_thread.cpp.

Referenced by BlackBoardLoggerPlugin::BlackBoardLoggerPlugin().

void BBLoggerThread::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.

See also:
Fawkes Thread Aspects

Reimplemented from fawkes::Thread.

Definition at line 128 of file log_thread.cpp.

References fawkes::BlackBoardInterfaceListener::bbil_add_data_interface(), fawkes::BlackBoardInterfaceListener::bbil_add_message_interface(), fawkes::BlackBoardInterfaceListener::bbil_add_writer_interface(), fawkes::BlackBoardAspect::blackboard, fawkes::LockQueue< Type >::clear(), fawkes::ClockAspect::clock, fawkes::BlackBoard::close(), fawkes::Interface::datasize(), fawkes::Logger::log_info(), fawkes::LoggingAspect::logger, fawkes::Thread::name(), fawkes::BlackBoard::open_for_reading(), fawkes::BlackBoard::open_for_writing(), fawkes::BlackBoard::register_listener(), fawkes::SwitchInterface::set_enabled(), fawkes::Interface::uid(), and fawkes::Interface::write().

void BBLoggerThread::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 334 of file log_thread.cpp.

References fawkes::Mutex::lock(), and fawkes::Mutex::unlock().

virtual void BBLoggerThread::run ( ) [inline, protected, virtual]

Stub to see name in backtrace for easier debugging.

See also:
Thread::run()

Reimplemented from fawkes::Thread.

Definition at line 76 of file log_thread.h.

void BBLoggerThread::set_enabled ( bool  enabled)

Enable or disable logging.

Parameters:
enabledtrue to enable logging, false to disable

Definition at line 232 of file log_thread.cpp.

References fawkes::Logger::log_info(), fawkes::LoggingAspect::logger, and fawkes::Thread::name().

Referenced by bb_interface_message_received().

void BBLoggerThread::set_threadlist ( fawkes::ThreadList thread_list)

Set threadlist and master status.

This copies the thread list and sets this thread as master thread. If you intend to use this method you must do so before the thread is initialized. You may only ever declare one thread as master.

Parameters:
thread_listlist of threads to notify on enable/disable events

Definition at line 256 of file log_thread.cpp.

Referenced by BlackBoardLoggerPlugin::BlackBoardLoggerPlugin().


The documentation for this class was generated from the following files:
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