Log4j 1.3alpha-5

org.apache.log4j.db
Class DBAppender

java.lang.Object
  |
  +--org.apache.log4j.spi.ComponentBase
        |
        +--org.apache.log4j.AppenderSkeleton
              |
              +--org.apache.log4j.db.DBAppender
All Implemented Interfaces:
Appender, Component, OptionHandler

public class DBAppender
extends AppenderSkeleton

The DBAppender inserts loggin events into three database tables in a format independent of the Java programming language. The three tables that DBAppender inserts to must exists before DBAppender can be used. These tables may be created with the help of SQL scripts found in the src/java/org/apache/log4j/db/dialect directory. There is a specific script for each of the most popular database systems. If the script for your particular type of database system is missing, it should be quite easy to write one, taking example on the already existing scripts. If you send them to us, we will gladly include missing scripts in future releases.

If the JDBC driver you are using supports the Statement.getGeneratedKeys()method introduced in JDBC 3.0 specification, then you are all set. Otherwise, there must be an SQLDialectappropriate for your database system. Currently, we have dialects for PostgreSQL, MySQL, Oracle and MsSQL. As mentioed previously, an SQLDialect is required only if the JDBC driver for your database system does not support the getGeneratedKeys method.

RDBMS supports
getGeneratedKeys() method
specific
SQLDialect support
PostgreSQL NO present and used
MySQL YES present, but not actually needed or used
Oracle YES present, but not actually needed or used
DB2 YES not present, and not needed or used
MsSQL YES not present, and not needed or used
HSQL NO present and used

Performance: Experiments show that writing a single event into the database takes approximately 50 milliseconds, on a "standard" PC. If pooled connections are used, this figure drops to under 10 milliseconds. Note that most JDBC drivers already ship with connection pooling support.

Configuration DBAppender can be configured programmatically, or using JoranConfigurator. Example scripts can be found in the tests/input/db directory.

Since:
1.3
Author:
Ceki Gülcü, Ray DeCampo

Field Summary
 
Fields inherited from class org.apache.log4j.AppenderSkeleton
closed, headFilter, layout, name, tailFilter, threshold
 
Fields inherited from class org.apache.log4j.spi.ComponentBase
repository
 
Constructor Summary
DBAppender()
           
 
Method Summary
 void activateOptions()
          Derived appenders should override this method if option structure requires it.
protected  void append(LoggingEvent event)
          Subclasses of AppenderSkeleton should implement this method to perform actual logging.
 void close()
          Release any resources allocated within the appender such as file handles, network connections, etc.
 ConnectionSource getConnectionSource()
           
 boolean getLocationInfo()
          Returns value of the LocationInfo property which determines whether caller's location info is written to the database.
 boolean requiresLayout()
           
 void setConnectionSource(ConnectionSource connectionSource)
           
 void setLocationInfo(boolean locationInfo)
          If true, the information written to the database will include caller's location information.
 
Methods inherited from class org.apache.log4j.AppenderSkeleton
addFilter, clearFilters, doAppend, finalize, getFilter, getFirstFilter, getLayout, getName, getThreshold, isAsSevereAsThreshold, setLayout, setName, setThreshold
 
Methods inherited from class org.apache.log4j.spi.ComponentBase
getLogger, setLoggerRepository
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.log4j.Appender
setLoggerRepository
 

Constructor Detail

DBAppender

public DBAppender()
Method Detail

activateOptions

public void activateOptions()
Description copied from class: AppenderSkeleton
Derived appenders should override this method if option structure requires it.

Specified by:
activateOptions in interface OptionHandler
Overrides:
activateOptions in class AppenderSkeleton

getConnectionSource

public ConnectionSource getConnectionSource()
Returns:
Returns the connectionSource.

setConnectionSource

public void setConnectionSource(ConnectionSource connectionSource)
Parameters:
connectionSource - The connectionSource to set.

append

protected void append(LoggingEvent event)
Description copied from class: AppenderSkeleton
Subclasses of AppenderSkeleton should implement this method to perform actual logging. See also AppenderSkeleton.doAppend method.

Specified by:
append in class AppenderSkeleton

close

public void close()
Description copied from interface: Appender
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.


requiresLayout

public boolean requiresLayout()

getLocationInfo

public boolean getLocationInfo()
Returns value of the LocationInfo property which determines whether caller's location info is written to the database.


setLocationInfo

public void setLocationInfo(boolean locationInfo)
If true, the information written to the database will include caller's location information. Due to performance concerns, by default no location information is written to the database.


Log4j 1.3alpha-5

Copyright 2000-2005 Apache Software Foundation.