OSB_LIB::LogBase Class Reference

Inheritance diagram for OSB_LIB::LogBase:

[legend]Collaboration diagram for OSB_LIB::LogBase:

[legend]List of all members.

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Detailed Description

Interface definition for the logging implementation.

Logging levels

• 1: fatal errors
• 2: errors
• 3: warnings
• 4: normal messages
• 5-7: debugging messages

Design comments
Because of the output operator template there is unfortunately no reasonable way to hide (and isolate) the optional logging to a secondary output stream.
The following however can be implemented in the concrete implementations of the interface:

• locking of the output streams for multithreaded applications
• buffering of log messages until the log file can be opened

The current design is weak because the class controls both, access to the output streams and the output format (the header of the logged message). Two new classes may replace the current class in a future version: LogAccess and LogFormat; AFAICS today, the interface of the purely static class Log however should not be affected.

Note:

The implementation of the virtual functions should not write to plog() (and slog()) directly, but redirect all output to itself:

      LogBase& ConsoleLog::nl()
      {
          *this << '\n';
          return *this;
      }

This way the output operators take automatically care of the log level and the optional outout to the secondary stream.

Definition at line 99 of file osblog.h.

Public Member Functions

• LogBase (int logLevel)

  Constructor with log level.
  

• virtual ~LogBase ()

  Virtual destructor.
  

• virtual void elog ()=0

  End the logging message with a new-line.
  

• virtual void endlog ()=0

  End the logging message without a new-line.
  

• virtual LogBase & nl ()=0

  Start a new line.
  

• virtual LogBase & head (char filler)=0

  Fill the start a new line with a character.
  

• template<typename T> LogBase & operator<< (const T &t)

  Output operator for arbitrary types and objects.
  

Start a logging message:

All functions call start() with the appropriate level.

• LogBase & fatal ()

  Start a fatal error message.
  

• LogBase & error ()

  Start an error message.
  

• LogBase & warn ()

  Start a warning.
  

• LogBase & info ()

  Start a normal message.
  

• LogBase & raw (int level)

  Start a message without standard header.
  

• LogBase & debug (int level)

  Start a debugging message.
  

Output manipulators.

• void operator<< (void(*func)(LogBase &))

  For Log::elog() and Log::endlog().
  

• LogBase & operator<< (LogBase &(*func)(LogBase &))

  Other manipulators of Log.
  

• LogBase & operator<< (const HeadFiller &filler)

  Start a new line and fill its head with a character.
  

IO stream manipulators.

• LogBase & operator<< (std::ostream &(*func)(std::ostream &))
• LogBase & operator<< (std::ios &(*func)(std::ios &))
• LogBase & operator<< (std::ios_base &(*func)(std::ios_base &))

Application interface:

• virtual int logLevel () const

  Get the current log level.
  

• virtual bool verbose () const

  Verbose (duplicate) messages on slog()?
  

• virtual void setLevel (int logLevel)

  Set the log level.
  

• virtual void setVerbose (bool on)

  Set verbose flag.
  

Protected Member Functions

• virtual LogBase & start (int level, bool noHead=false)=0

  Start a log message.
  

• virtual std::ostream & plog ()=0

  Get the primary output stream.
  

• virtual std::ostream * slog ()=0

  Get the secondary output stream.
  

• bool mustLog () const

  Write current log message?
  

Protected Attributes

• int logLevel_

  The log level: messages with a greater level are suppressed.
  

• int curLevel_

  The log level of the current message.
  

• bool verbose_

  Flag to duplicate messages on slog().
  

• bool noHead_

  Flag to suppress message header and indentation.
  

• bool useIndent_

  Flag to print indent_.
  

• std::string indent_

  Indent of next output.
  

Classes

• struct HeadFiller

  Structure to hold the filler for the line header. More...
  

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Constructor & Destructor Documentation

OSB_LIB::LogBase::LogBase

(

int

logLevel

)

[explicit]

Constructor with log level.

virtual OSB_LIB::LogBase::~LogBase

(

)

[virtual]

Virtual destructor.

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Member Function Documentation

LogBase & OSB_LIB::LogBase::debug

(

int

level

)

[inline]

Start a debugging message.

Parameters:

level

Debugging level (1-3): 1 corresponds to log level 5.

The library only uses debug levels 1-3. An application may use higher levels.

Definition at line 626 of file osblog.h.

References start().

Referenced by OSB_LIB::Log::debug().

virtual void OSB_LIB::LogBase::elog

(

)

[pure virtual]

End the logging message with a new-line.

Attention:

A concrete implementation that uses locking should unlock in this method.

Implemented in OSB_LIB::ConsoleLog.

Referenced by OSB_LIB::Log::elog().

virtual void OSB_LIB::LogBase::endlog

(

)

[pure virtual]

End the logging message without a new-line.

Attention:

A concrete implementation that uses locking should unlock in this method.

Implemented in OSB_LIB::ConsoleLog.

Referenced by OSB_LIB::Log::endlog().

LogBase & OSB_LIB::LogBase::error

(

)

[inline]

Start an error message.

Definition at line 606 of file osblog.h.

References start().

Referenced by OSB_LIB::Log::error().

LogBase & OSB_LIB::LogBase::fatal

(

)

[inline]

Start a fatal error message.

Definition at line 601 of file osblog.h.

References start().

Referenced by OSB_LIB::Log::fatal().

virtual LogBase& OSB_LIB::LogBase::head

(

char

filler

)

[pure virtual]

Fill the start a new line with a character.

Parameters:

filler

Filler to use.

See Log::head() for an usage example.

Implemented in OSB_LIB::ConsoleLog.

Referenced by operator<<().

LogBase & OSB_LIB::LogBase::info

(

)

[inline]

Start a normal message.

Definition at line 616 of file osblog.h.

References start().

Referenced by OSB_LIB::Log::info().

virtual int OSB_LIB::LogBase::logLevel

(

)

const [virtual]

Get the current log level.

Attention:

A concrete implementation that uses locking should overwrite this method.

Referenced by OSB_LIB::Log::logLevel().

bool OSB_LIB::LogBase::mustLog

(

)

const [inline, protected]

Write current log message?

Returns:

true if logLevel_ is -1 or >= curLevel_.

Locking
The base class calls this member function only from output operators that write to plog().

Definition at line 631 of file osblog.h.

References curLevel_, and logLevel_.

Referenced by operator<<().

virtual LogBase& OSB_LIB::LogBase::nl

(

)

[pure virtual]

Start a new line.

Writes a '\n' and the indent for the next line.
If you want to avoid the indent output the newline character directly.

Implemented in OSB_LIB::ConsoleLog.

Referenced by OSB_LIB::Log::nl().

LogBase & OSB_LIB::LogBase::operator<<

(

std::ios_base &(*)(std::ios_base &)

func

)

[inline]

Definition at line 705 of file osblog.h.

References mustLog(), plog(), slog(), and verbose_.

LogBase & OSB_LIB::LogBase::operator<<

(

std::ios &(*)(std::ios &)

func

)

[inline]

Definition at line 691 of file osblog.h.

References mustLog(), plog(), slog(), and verbose_.

LogBase & OSB_LIB::LogBase::operator<<

(

std::ostream &(*)(std::ostream &)

func

)

[inline]

Definition at line 677 of file osblog.h.

References mustLog(), plog(), slog(), and verbose_.

template<typename T>

LogBase & OSB_LIB::LogBase::operator<<

(

const T &

t

)

[inline]

Output operator for arbitrary types and objects.

Definition at line 660 of file osblog.h.

References indent_, mustLog(), plog(), slog(), useIndent_, and verbose_.

LogBase & OSB_LIB::LogBase::operator<<

(

const HeadFiller &

filler

)

[inline]

Start a new line and fill its head with a character.

Definition at line 652 of file osblog.h.

References OSB_LIB::LogBase::HeadFiller::filler_, and head().

LogBase & OSB_LIB::LogBase::operator<<

(

LogBase &(*)(LogBase &)

func

)

[inline]

Other manipulators of Log.

Definition at line 645 of file osblog.h.

void OSB_LIB::LogBase::operator<<

(

void(*)(LogBase &)

func

)

[inline]

For Log::elog() and Log::endlog().

Definition at line 638 of file osblog.h.

virtual std::ostream& OSB_LIB::LogBase::plog

(

)

[protected, pure virtual]

Get the primary output stream.

Implemented in OSB_LIB::ConsoleLog.

Referenced by operator<<().

LogBase & OSB_LIB::LogBase::raw

(

int

level

)

[inline]

Start a message without standard header.

Definition at line 621 of file osblog.h.

References start().

Referenced by OSB_LIB::Log::raw().

virtual void OSB_LIB::LogBase::setLevel

(

int

logLevel

)

[virtual]

Set the log level.

Parameters:

logLevel

New log level to be used.

Attention:

A concrete implementation that uses locking should overwrite this method.

Referenced by OSB_LIB::Log::setLevel().

virtual void OSB_LIB::LogBase::setVerbose

(

bool

on

)

[virtual]

Set verbose flag.

Attention:

A concrete implementation that uses locking should overwrite this method.

Referenced by OSB_LIB::Log::setVerbose().

virtual std::ostream* OSB_LIB::LogBase::slog

(

)

[protected, pure virtual]

Get the secondary output stream.

Implemented in OSB_LIB::ConsoleLog.

Referenced by operator<<().

virtual LogBase& OSB_LIB::LogBase::start	(	int	level,
		bool	noHead = false
	)			[protected, pure virtual]

Start a log message.

Parameters:

	level	Log level as decscribed above.
	noHead	Flag to suppress message header and indentation.

Concrete implementations should set curLevel_ to level, else all messages will be output.
Because of locking issues this can not be done in the base class.

Attention:

A concrete implementation that uses locking should lock in this method.

Implemented in OSB_LIB::ConsoleLog.

Referenced by debug(), error(), fatal(), info(), raw(), and warn().

virtual bool OSB_LIB::LogBase::verbose

(

)

const [virtual]

Verbose (duplicate) messages on slog()?

Attention:

A concrete implementation that uses locking should overwrite this method.

Referenced by OSB_LIB::Log::verbose().

LogBase & OSB_LIB::LogBase::warn

(

)

[inline]

Start a warning.

Definition at line 611 of file osblog.h.

References start().

Referenced by OSB_LIB::Log::warn().

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Member Data Documentation

int OSB_LIB::LogBase::curLevel_ [protected]

The log level of the current message.

Definition at line 287 of file osblog.h.

Referenced by mustLog().

std::string OSB_LIB::LogBase::indent_ [protected]

Indent of next output.

Definition at line 295 of file osblog.h.

Referenced by operator<<().

int OSB_LIB::LogBase::logLevel_ [protected]

The log level: messages with a greater level are suppressed.

-1 means that all messages are output.

Definition at line 285 of file osblog.h.

Referenced by mustLog().

bool OSB_LIB::LogBase::noHead_ [protected]

Flag to suppress message header and indentation.

Definition at line 291 of file osblog.h.

bool OSB_LIB::LogBase::useIndent_ [protected]

Flag to print indent_.

Definition at line 293 of file osblog.h.

Referenced by operator<<().

bool OSB_LIB::LogBase::verbose_ [protected]

Flag to duplicate messages on slog().

Definition at line 289 of file osblog.h.

Referenced by operator<<().

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

• osblog.h

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