JDBCAppender (reload4j 1.2.25 API)

java.lang.Object
- org.apache.log4j.AppenderSkeleton
- - org.apache.log4j.jdbc.JDBCAppender

All Implemented Interfaces:

Appender, OptionHandler
```
public class JDBCAppender
extends AppenderSkeleton
implements Appender
```
The JDBCAppender provides for sending log events to a database. It does not log exceptions.
JDBCAppender shipping in 1.2.18.2 produces PreparedStatement instances. Thanks to the remarkable work of Vladimir Sitnikov JDBCAppender now interprets the SQL expression on the fly and inserts new events using PreparedStartement instances. Note that the table column types are restricted to those types compatible with Java's String.

Versions 1.2.18.0 and prior are vulnerable to SQL injection attacks..

Each append call adds to an ArrayList buffer. When the buffer is filled each log event is placed in a sql statement (configurable) and executed.

BufferSize, db URL, User, & Password are configurable options in the standard log4j fashion.

The setSql(String sql) sets the SQL statement to be used for logging -- this statement is sent to a PatternLayout (either created automatically by the appender or added by the user). Therefore by default all the conversion patterns in PatternLayout can be used inside of the statement. (see the test cases for examples).

As mentioned earlier, the produced SQL is translated in an additional phase to use PreparedStatement.

For use as a base class:
- Override getConnection() to pass any connection you want. Typically this is used to enable application wide connection pooling.
- Override closeConnection(Connection con) -- if you override getConnection make sure to implement closeConnection to handle the connection you generated. Typically this would return the connection to the pool it came from.
- As of 1.2.18.1 getLogStatement(org.apache.log4j.spi.LoggingEvent) is no longer in use.
Author:

Kevin Steppe (ksteppe@pacbell.net)

Field Summary

Fields
Modifier and Type	Field and Description
`protected ArrayList<LoggingEvent>`	`buffer` ArrayList holding the buffer of Logging Events.
`protected int`	`bufferSize` size of LoggingEvent buffer before writting to the database.
`protected Connection`	`connection` Connection used by default.
`protected String`	`databasePassword` User to use for default connection handling
`protected String`	`databaseURL` URL of the DB for default connection handling
`protected String`	`databaseUser` User to connect as for default connection handling
`protected String`	`sqlStatement` Stores the string given to the pattern layout for conversion into a SQL statement, eg: insert into LogTable (Thread, Class, Message) values ("%t", "%c", "%m").

Fields inherited from class org.apache.log4j.AppenderSkeleton
closed, errorHandler, headFilter, layout, name, tailFilter, threshold

Constructor Summary

Constructors
Constructor and Description

JDBCAppender()

Constructors
Constructor and Description
`JDBCAppender()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`activateOptions()` Derived appenders should override this method if option structure requires it.
`void`	`append(LoggingEvent event)` Adds the event to the buffer.
`void`	`close()` Closes the appender, flushing the buffer first then closing the default connection if it is open.
`protected void`	`closeConnection(Connection con)` Override this to return the connection to a pool, or to clean up the resource.
`protected void`	`execute(String sql)` Override this to provide an alertnate method of getting connections (such as caching).
`void`	`finalize()` closes the appender before disposal
`void`	`flushBuffer()` loops through the buffer of LoggingEvents, gets a sql string from getLogStatement() and sends it to execute().
`int`	`getBufferSize()`
`protected Connection`	`getConnection()` Override this to link with your connection pooling system.
`boolean`	`getLocationInfo()` Gets whether the location of the logging request call should be captured.
`protected String`	`getLogStatement(LoggingEvent event)` As of 1.2.18.1 `getLogStatement(org.apache.log4j.spi.LoggingEvent)` is no longer in use.
`String`	`getPassword()`
`String`	`getSql()` Returns pre-formated statement eg: insert into LogTable (msg) values ("%m")
`String`	`getURL()`
`String`	`getUser()`
`boolean`	`requiresLayout()` JDBCAppender requires a layout.
`void`	`setBufferSize(int newBufferSize)`
`void`	`setDriver(String driverClass)` Ensures that the given driver class has been loaded for sql connection creation.
`void`	`setLocationInfo(boolean flag)` The LocationInfo option takes a boolean value.
`void`	`setPassword(String password)`
`void`	`setSql(String s)`
`void`	`setURL(String url)`
`void`	`setUser(String user)`

Methods inherited from class org.apache.log4j.AppenderSkeleton
addFilter, clearFilters, doAppend, getErrorHandler, getFilter, getFirstFilter, getLayout, getName, getThreshold, isAsSevereAsThreshold, setErrorHandler, setLayout, setName, setThreshold

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
addFilter, clearFilters, doAppend, getErrorHandler, getFilter, getLayout, getName, setErrorHandler, setLayout, setName

- Field Detail
  - databaseURL
```
protected String databaseURL
```
    URL of the DB for default connection handling
  - databaseUser
```
protected String databaseUser
```
    User to connect as for default connection handling
  - databasePassword
```
protected String databasePassword
```
    User to use for default connection handling
  - connection
```
protected Connection connection
```
    Connection used by default. The connection is opened the first time it is needed and then held open until the appender is closed (usually at garbage collection). This behavior is best modified by creating a sub-class and overriding the getConnection and closeConnection methods.
  - sqlStatement
```
protected String sqlStatement
```
    Stores the string given to the pattern layout for conversion into a SQL statement, eg: insert into LogTable (Thread, Class, Message) values ("%t", "%c", "%m").
    Be careful of quotes in your messages!
    Also see PatternLayout.
  - bufferSize
```
protected int bufferSize
```
    size of LoggingEvent buffer before writting to the database. Default is 1.
  - buffer
```
protected ArrayList<LoggingEvent> buffer
```
    ArrayList holding the buffer of Logging Events.
- Constructor Detail
  - JDBCAppender
```
public JDBCAppender()
```
- 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
  - getLocationInfo
```
public boolean getLocationInfo()
```
    Gets whether the location of the logging request call should be captured.
    
    Returns:
    
    the current value of the LocationInfo option.
    
    Since:
    
    1.2.16
  - setLocationInfo
```
public void setLocationInfo(boolean flag)
```
    The LocationInfo option takes a boolean value. By default, it is set to false which means there will be no effort to extract the location information related to the event. As a result, the event that will be ultimately logged will likely to contain the wrong location information (if present in the log format).
    
    Location information extraction is comparatively very slow and should be avoided unless performance is not a concern.
    
    Parameters:
    
    flag - true if location information should be extracted.
    
    Since:
    
    1.2.16
  - append
```
public void append(LoggingEvent event)
```
    Adds the event to the buffer. When full the buffer is flushed.
    
    Specified by:
    
    append in class AppenderSkeleton
  - getLogStatement
```
protected String getLogStatement(LoggingEvent event)
```
    As of 1.2.18.1 getLogStatement(org.apache.log4j.spi.LoggingEvent) is no longer in use.
    
    Parameters:
    
    event -
  - execute
```
protected void execute(String sql)
                throws SQLException
```
    Override this to provide an alertnate method of getting connections (such as caching). One method to fix this is to open connections at the start of flushBuffer() and close them at the end. I use a connection pool outside of JDBCAppender which is accessed in an override of this method.
    
    Throws:
    
    SQLException
  - closeConnection
```
protected void closeConnection(Connection con)
```
    Override this to return the connection to a pool, or to clean up the resource.
    The default behavior holds a single connection open until the appender is closed (typically when garbage collected).
  - getConnection
```
protected Connection getConnection()
                            throws SQLException
```
    Override this to link with your connection pooling system.
    By default this creates a single connection which is held open until the object is garbage collected.
    
    Throws:
    
    SQLException
  - close
```
public void close()
```
    Closes the appender, flushing the buffer first then closing the default connection if it is open.
    
    Specified by:
    
    close in interface Appender
  - flushBuffer
```
public void flushBuffer()
```
    loops through the buffer of LoggingEvents, gets a sql string from getLogStatement() and sends it to execute(). Errors are sent to the errorHandler.
    If a statement fails the LoggingEvent stays in the buffer!
  - finalize
```
public void finalize()
```
    closes the appender before disposal
    
    Overrides:
    
    finalize in class AppenderSkeleton
  - requiresLayout
```
public boolean requiresLayout()
```
    JDBCAppender requires a layout.
    
    Specified by:
    
    requiresLayout in interface Appender
  - setSql
```
public void setSql(String s)
```
  - getSql
```
public String getSql()
```
    Returns pre-formated statement eg: insert into LogTable (msg) values ("%m")
  - setUser
```
public void setUser(String user)
```
  - setURL
```
public void setURL(String url)
```
  - setPassword
```
public void setPassword(String password)
```
  - setBufferSize
```
public void setBufferSize(int newBufferSize)
```
  - getUser
```
public String getUser()
```
  - getURL
```
public String getURL()
```
  - getPassword
```
public String getPassword()
```
  - getBufferSize
```
public int getBufferSize()
```
  - setDriver
```
public void setDriver(String driverClass)
```
    Ensures that the given driver class has been loaded for sql connection creation.

Class JDBCAppender

Field Summary

Fields inherited from class org.apache.log4j.AppenderSkeleton

Constructor Summary

Method Summary

Methods inherited from class org.apache.log4j.AppenderSkeleton

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.log4j.Appender

Field Detail

databaseURL

databaseUser

databasePassword

connection

sqlStatement

bufferSize

buffer

Constructor Detail

JDBCAppender

Method Detail

activateOptions

getLocationInfo

setLocationInfo

append

getLogStatement

execute

closeConnection

getConnection

close

flushBuffer

finalize

requiresLayout

setSql

getSql

setUser

setURL

setPassword

setBufferSize

getUser

getURL

getPassword

getBufferSize

setDriver