org.apache.log4j.jdbc
Class JDBCAppender
- Appender, OptionHandler
public class JDBCAppender
WARNING: This version of JDBCAppender
is very likely to be completely replaced in the future. Moreoever,
it does not log exceptions.
The JDBCAppender provides for sending log events to a database.
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 ways.
The
setSql(String sql)
sets the SQL statement to be
used for logging -- this statement is sent to a
PatternLayout
(either created automaticly 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)
Overriding the
getLogStatement(LoggingEvent)
method allows more
explicit control of the statement used for logging.
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.
- Override
getLogStatement(LoggingEvent event)
to
produce specialized or dynamic statements. The default uses the
sql option value.
protected ArrayList | buffer - ArrayList holding the buffer of Logging Events.
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protected int | bufferSize - size of LoggingEvent buffer before writting to the database.
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protected Connection | connection - Connection used by default.
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protected String | databasePassword - User to use for default connection handling
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protected String | databaseURL - URL of the DB for default connection handling
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protected String | databaseUser - User to connect as for default connection handling
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protected ArrayList | removes - Helper object for clearing out the buffer
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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").
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void | append(LoggingEvent event) - Adds the event to the buffer.
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void | close() - Closes the appender, flushing the buffer first then closing the default
connection if it is open.
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protected void | closeConnection(Connection con) - Override this to return the connection to a pool, or to clean up the
resource.
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protected void | execute(String sql) -
Override this to provide an alertnate method of getting
connections (such as caching).
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void | finalize() - closes the appender before disposal
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void | flushBuffer() - loops through the buffer of LoggingEvents, gets a
sql string from getLogStatement() and sends it to execute().
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int | getBufferSize()
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protected Connection | getConnection() - Override this to link with your connection pooling system.
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protected String | getLogStatement(LoggingEvent event) - By default getLogStatement sends the event to the required Layout object.
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String | getPassword()
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String | getSql() - Returns pre-formated statement eg: insert into LogTable (msg) values ("%m")
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String | getURL()
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String | getUser()
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boolean | requiresLayout() - JDBCAppender requires a layout.
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void | setBufferSize(int newBufferSize)
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void | setDriver(String driverClass) - Ensures that the given driver class has been loaded for sql connection
creation.
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void | setPassword(String password)
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void | setSql(String s)
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void | setURL(String url)
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void | setUser(String user)
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activateOptions , addFilter , append , clearFilters , doAppend , finalize , getErrorHandler , getFilter , getFirstFilter , getLayout , getName , getThreshold , isAsSevereAsThreshold , setErrorHandler , setLayout , setName , setThreshold |
buffer
protected ArrayList buffer
ArrayList holding the buffer of Logging Events.
bufferSize
protected int bufferSize
size of LoggingEvent buffer before writting to the database.
Default is 1.
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.
databasePassword
protected String databasePassword
User to use for default connection handling
databaseURL
protected String databaseURL
URL of the DB for default connection handling
databaseUser
protected String databaseUser
User to connect as for default connection handling
removes
protected ArrayList removes
Helper object for clearing out the buffer
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.
JDBCAppender
public JDBCAppender()
close
public void close()
Closes the appender, flushing the buffer first then closing the default
connection if it is open.
- close in interface Appender
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).
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.
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!
getBufferSize
public int getBufferSize()
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.
getLogStatement
protected String getLogStatement(LoggingEvent event)
By default getLogStatement sends the event to the required Layout object.
The layout will format the given pattern into a workable SQL string.
Overriding this provides direct access to the LoggingEvent
when constructing the logging statement.
getPassword
public String getPassword()
getSql
public String getSql()
Returns pre-formated statement eg: insert into LogTable (msg) values ("%m")
getURL
public String getURL()
getUser
public String getUser()
requiresLayout
public boolean requiresLayout()
JDBCAppender requires a layout.
- requiresLayout in interface Appender
setBufferSize
public void setBufferSize(int newBufferSize)
setDriver
public void setDriver(String driverClass)
Ensures that the given driver class has been loaded for sql connection
creation.
setPassword
public void setPassword(String password)
setSql
public void setSql(String s)
setURL
public void setURL(String url)
setUser
public void setUser(String user)
Copyright 2000-2005 Apache Software Foundation.