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ODBCAppender Class Reference

Inheritance diagram for ODBCAppender:

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Collaboration diagram for ODBCAppender:

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List of all members.

Public Member Functions

virtual void setOption (const String &option, const String &value)
void append (const spi::LoggingEventPtr &event)
virtual void close ()
void flushBuffer ()
virtual bool requiresLayout () const
void setSql (const String &s)
const String & getSql () const

Protected Member Functions

String getLogStatement (const spi::LoggingEventPtr &event) const
void execute (const String &sql)
virtual void closeConnection (SQLHDBC con)
virtual SQLHDBC getConnection ()

Protected Attributes

String databaseURL
String databaseUser
String databasePassword
SQLHDBC connection
String sqlStatement
size_t bufferSize
std::list< spi::LoggingEventPtr > buffer

Detailed Description

WARNING: This version of ODBCAppender is very likely to be completely replaced in the future. Moreoever, it does not log exceptions.

The ODBCAppender 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 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 -- 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 to produce specialized or dynamic statements. The default uses the sql option value.

Member Function Documentation

void append (  const spi::LoggingEventPtr &  event  )  [virtual]
 

Adds the event to the buffer. When full the buffer is flushed.

Implements AppenderSkeleton.

void close (   )  [virtual]
 

Closes the appender, flushing the buffer first then closing the default connection if it is open.

Implements Appender.

void closeConnection (  SQLHDBC  con  )  [protected, virtual]
 

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).

void execute (  const String &  sql  )  [protected]
 

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 ODBCAppender which is accessed in an override of this method.

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!

SQLHDBC getConnection (   )  [protected, virtual]
 

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.

String getLogStatement (  const spi::LoggingEventPtr &  event  )  const [protected]
 

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.

const String& getSql (   )  const [inline]
 

Returns pre-formated statement eg: insert into LogTable (msg) values ("%m")

virtual bool requiresLayout (   )  const [inline, virtual]
 

ODBCAppender requires a layout.

Implements Appender.

void setOption (  const String &  option,
const String &  value
)  [virtual]
 

Set options

Reimplemented from AppenderSkeleton.

void setSql (  const String &  s  ) 
 

Set pre-formated statement eg: insert into LogTable (msg) values ("%m")

Member Data Documentation

std::list<spi::LoggingEventPtr> buffer [protected]
 

ArrayList holding the buffer of Logging Events.

size_t bufferSize [protected]
 

size of LoggingEvent buffer before writting to the database. Default is 1.

SQLHDBC connection [protected]
 

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.

String databasePassword [protected]
 

User to use for default connection handling

String databaseURL [protected]
 

URL of the DB for default connection handling

String databaseUser [protected]
 

User to connect as for default connection handling

String sqlStatement [protected]
 

Stores the string given to the pattern layout for conversion into a SQL statement, eg: insert into LogTable (Thread, File, Message) values ("%t", "%F", "%m")

Be careful of quotes in your messages!

Also see PatternLayout.

The documentation for this class was generated from the following files:
  • odbcappender.h
  • odbcappender.cpp
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