log4cxx::db::DBAppender Class Reference

The DBAppender lets you log messages to a database. More...

#include <dbappender.h>

Inheritance diagram for log4cxx::db::DBAppender:

Public Member Functions
	DBAppender ()
virtual	~DBAppender ()
void	setOption (const LogString &option, const LogString &value) override
	Set option to value.
void	activateOptions (helpers::Pool &p) override
	Activate the specified options.
void	append (const spi::LoggingEventPtr &event, helpers::Pool &) override
	Adds the event to the buffer.
void	close () override
	Release any resources allocated within the appender such as file handles, network connections, etc.
bool	requiresLayout () const override
	DBAppender does not require a layout.
void	setSql (const LogString &s)
	Set pre-formated statement eg: insert into LogTable (msg) values (?)
const LogString &	getSql () const
	Returns pre-formated statement eg: insert into LogTable (msg) values (?)
Public Member Functions inherited from log4cxx::AppenderSkeleton
	AppenderSkeleton ()
	AppenderSkeleton (const LayoutPtr &layout)
virtual	~AppenderSkeleton ()
void	finalize ()
	Finalize this appender by calling the derived class' close method.
void	activateOptions (helpers::Pool &) override
	Activate the options that were previously set with calls to option setters.
void	setOption (const LogString &option, const LogString &value) override
	Set option to value.
void	addFilter (const spi::FilterPtr newFilter) override
	Add a filter to end of the filter list.
void	clearFilters () override
	Clear the filters chain.
const spi::ErrorHandlerPtr	getErrorHandler () const
	Return the currently set spi::ErrorHandler for this Appender.
spi::FilterPtr	getFilter () const override
	Returns the head Filter.
const spi::FilterPtr	getFirstFilter () const
	Return the first filter in the filter chain for this Appender.
LayoutPtr	getLayout () const override
	Returns the layout of this appender.
LogString	getName () const override
	Returns the name of this Appender.
const LevelPtr	getThreshold () const
	Returns this appenders threshold level.
bool	isAsSevereAsThreshold (const LevelPtr &level) const
	Check whether the message level is below the appender's threshold.
void	doAppend (const spi::LoggingEventPtr &event, helpers::Pool &pool) override
	This method performs threshold checks and invokes filters before delegating actual logging to the subclasses specific AppenderSkeleton::append method.
void	setErrorHandler (const spi::ErrorHandlerPtr eh)
	Set the ErrorHandler for this Appender.
void	setLayout (const LayoutPtr layout1) override
	Set the layout for this appender.
void	setName (const LogString &name1) override
	Set the name of this Appender.
void	setThreshold (const LevelPtr &threshold)
	Set the threshold level.
Public Member Functions inherited from log4cxx::Appender
virtual	~Appender ()
virtual void	addFilter (const spi::FilterPtr newFilter)=0
	Add a filter to the end of the filter list.
virtual spi::FilterPtr	getFilter () const =0
	Returns the head Filter.
virtual void	clearFilters ()=0
	Clear the list of filters by removing all the filters in it.
virtual void	close ()=0
	Release any resources allocated within the appender such as file handles, network connections, etc.
virtual void	doAppend (const spi::LoggingEventPtr &event, log4cxx::helpers::Pool &pool)=0
	Log in Appender specific way.
virtual LogString	getName () const =0
	Get the name of this appender.
virtual void	setLayout (const LayoutPtr layout)=0
	Set the Layout for this appender.
virtual LayoutPtr	getLayout () const =0
	Returns this appenders layout.
virtual void	setName (const LogString &name)=0
	Set the name of this appender.
virtual bool	requiresLayout () const =0
	Configurators call this method to determine if the appender requires a layout.
Public Member Functions inherited from log4cxx::spi::OptionHandler
virtual	~OptionHandler ()
virtual void	activateOptions (helpers::Pool &p)=0
	Activate the options that were previously set with calls to option setters.
virtual void	setOption (const LogString &option, const LogString &value)=0
	Set option to value.
Public Member Functions inherited from log4cxx::helpers::Object
virtual	~Object ()
virtual const helpers::Class &	getClass () const =0
virtual bool	instanceof (const Class &clazz) const =0
virtual const void *	cast (const Class &clazz) const =0

Additional Inherited Members
Protected Member Functions inherited from log4cxx::AppenderSkeleton
	AppenderSkeleton (LOG4CXX_PRIVATE_PTR(AppenderSkeletonPrivate) priv)
virtual void	append (const spi::LoggingEventPtr &event, log4cxx::helpers::Pool &p)=0
	Subclasses of AppenderSkeleton should implement this method to perform actual logging.
void	doAppendImpl (const spi::LoggingEventPtr &event, log4cxx::helpers::Pool &pool)

Detailed Description

The DBAppender lets you log messages to a database.

This utilizes the APR's database support in order to provide a single way of logging to multiple databases, not just ODBC as the ODBCAppender does.

The following SQL script is an example of how you may make a table that stores log messages:

CREATE TABLE logs (
 logger VARCHAR(200),
 time DATETIME,
 level CHAR(5),
 file VARCHAR(200),
 line_number INT,
 message VARCHAR(1000)
);

Once you have defined the table, you must define the order in which the columns are formatted when they are inserted along with the insert statement.

Using APR, the following insert statement can be used to insert log statements: INSERT INTO logs (logger, time, level, file, line_number, message) VALUES (s, pDa, s, s, d, s) The values to insert must be formatted appropriately and in the correct order. In order to do this, the parameter ColumnMapping must be specified as many times as there are columns to insert.

The following table shows the conversion specifiers. These are effectively the same as the conversion patterns provided by PatternLayout but with more descriptive names:

Conversion Specifier	Effect
logger	The name of the logger(e.g. com.foo.bar)
class	The class that the log message was in
time	The time of the log message
shortfilename	The short filename where the log message is from
fullfilename	The full filename where the log mesasge is from
location	The location of the log message
line	The line where the log message appears
message	The log message
method	The method where the message was logged
level	The level of the log message
thread	The thread where this message was logged
threadname	The name of the thread that logged the message
ndc	The NDC(nested diagnostic context) of the log

Other parameters that are important:

Parameter name	Usage
DriverName	The name of the database driver to load(ex: odbc, sqlite3)
DriverParams	A string of parameters to pass to the driver. This is database-specific
DatabaseName	The name of the database to use when connecting to the server

The following code shows how you might connect to an ODBC data source and insert the log messages:

<appender name="SqlDBAppender" class="DBAppender">
  <param name="drivername" value="odbc"/>
  <param name="DriverParams" value="DATASOURCE=MariaDB-server"/>
  <param name="DatabaseName" value="example_database"/>
  <param name="sql" value="INSERT INTO logs (logger, time, level, file, line_number, message) VALUES (%s, %pDa, %s, %s, %d, %s)" />
  <param name="ColumnMapping" value="logger"/>
  <param name="ColumnMapping" value="time"/>
  <param name="ColumnMapping" value="level"/>
  <param name="ColumnMapping" value="shortfilename"/>
  <param name="ColumnMapping" value="line"/>
  <param name="ColumnMapping" value="message"/>
</appender>

A similar configuration can be used for SQLite:

<appender name="SqlDBAppender" class="DBAppender">
  <param name="drivername" value="sqlite3"/>
  <param name="DriverParams" value="/path/to/database.db"/>
  <param name="sql" value="INSERT INTO logs (logger, time, level, file, line_number, message) VALUES (%s, %pDa, %s, %s, %d, %s)" />
  <param name="ColumnMapping" value="logger"/>
  <param name="ColumnMapping" value="time"/>
  <param name="ColumnMapping" value="level"/>
  <param name="ColumnMapping" value="shortfilename"/>
  <param name="ColumnMapping" value="line"/>
  <param name="ColumnMapping" value="message"/>
</appender>

Constructor & Destructor Documentation

DBAppender()

log4cxx::db::DBAppender::DBAppender

(

)

~DBAppender()

virtual log4cxx::db::DBAppender::~DBAppender ( )

virtual

Member Function Documentation

activateOptions()

void log4cxx::db::DBAppender::activateOptions ( helpers::Pool &  p )

overridevirtual

Activate the specified options.

Reimplemented from log4cxx::AppenderSkeleton.

append()

void log4cxx::db::DBAppender::append ( const spi::LoggingEventPtr &  event, helpers::Pool &    )

overridevirtual

Adds the event to the buffer.

When full the buffer is flushed.

Implements log4cxx::AppenderSkeleton.

close()

void log4cxx::db::DBAppender::close ( )

overridevirtual

Release any resources allocated within the appender such as file handles, network connections, etc.

It is a programming error to append to a closed appender.

Implements log4cxx::Appender.

getSql()

const LogString & log4cxx::db::DBAppender::getSql

(

)

const

Returns pre-formated statement eg: insert into LogTable (msg) values (?)

requiresLayout()

bool log4cxx::db::DBAppender::requiresLayout ( ) const

inlineoverridevirtual

DBAppender does not require a layout.

Implements log4cxx::Appender.

setOption()

void log4cxx::db::DBAppender::setOption ( const LogString &  option, const LogString &  value  )

overridevirtual

Set option to value.

Supported options	Supported values	Default value
DriverName	{any}	-
DriverParams	{any}	-
DatabaseName	{any}	-
SQL	{any}	-
ColumnMapping	(^)	-

(^) One value for each '%' character in the SQL value.

See also

AppenderSkeleton::setOption()

Reimplemented from log4cxx::AppenderSkeleton.

setSql()

void log4cxx::db::DBAppender::setSql

(

const LogString &

s

)

Set pre-formated statement eg: insert into LogTable (msg) values (?)

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

• dbappender.h