# ODBCAppender Class Reference

Inherits AppenderSkeleton.

List of all members.

## 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.

## Public Member Functions

| ODBCAppender ()
virtual | ~ODBCAppender ()
virtual void | setOption (const LogString &option, const LogString &value)
| Set options.
virtual void | activateOptions (log4cxx::helpers::Pool &p)
| Activate the specified options.
void | append (const spi::LoggingEventPtr &event, log4cxx::helpers::Pool &)
| Adds the event to the buffer.
virtual void | close ()
| Closes the appender, flushing the buffer first then closing the default connection if it is open.
virtual void | flushBuffer (log4cxx::helpers::Pool &p)
| loops through the buffer of LoggingEvents, gets a sql string from getLogStatement() and sends it to execute().
virtual bool | requiresLayout () const
| ODBCAppender requires a layout.
void | setSql (const LogString &s)
| Set pre-formated statement eg: insert into LogTable (msg) values ("%m").
const LogString & | getSql () const
| Returns pre-formated statement eg: insert into LogTable (msg) values ("%m").
void | setUser (const LogString &user)
void | setURL (const LogString &url)
void | setPassword (const LogString &password)
void | setBufferSize (size_t newBufferSize)
const LogString & | getUser () const
const LogString & | getURL () const
const LogString & | getPassword () const
size_t | getBufferSize () const

## Protected Types

typedef void * | SQLHDBC
typedef void * | SQLHENV
typedef void * | SQLHANDLE
typedef short | SQLSMALLINT

## Protected Member Functions

LogString | getLogStatement (const spi::LoggingEventPtr &event, helpers::Pool &p) const
| By default getLogStatement sends the event to the required Layout object.
virtual void | execute (const LogString &sql, log4cxx::helpers::Pool &p)
| Override this to provide an alertnate method of getting connections (such as caching).
virtual void | closeConnection (SQLHDBC con)
| Override this to return the connection to a pool, or to clean up the resource.
virtual SQLHDBC | getConnection (log4cxx::helpers::Pool &p)
| Override this to link with your connection pooling system.

## Protected Attributes

LogString | databaseURL
| URL of the DB for default connection handling.
LogString | databaseUser
| User to connect as for default connection handling.
LogString | databasePassword
| User to use for default connection handling.
SQLHDBC | connection
| Connection used by default.
SQLHENV | env
LogString | sqlStatement
| 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").
size_t | bufferSize
| size of LoggingEvent buffer before writing to the database.
std::list< spi::LoggingEventPtr > | buffer
| ArrayList holding the buffer of Logging Events.

## Member Typedef Documentation

typedef void* SQLHANDLE `[protected]`

typedef void* SQLHDBC `[protected]`

typedef void* SQLHENV `[protected]`

typedef short SQLSMALLINT `[protected]`

## Constructor & Destructor Documentation

ODBCAppender | ( |  | ) |

virtual ~ODBCAppender | ( |  | ) | `[virtual]`

## Member Function Documentation

virtual void activateOptions | ( | log4cxx::helpers::Pool & | p | ) | `[virtual]`

| Activate the specified options. Reimplemented from AppenderSkeleton.

void append | ( | const spi::LoggingEventPtr & | event,
|  | log4cxx::helpers::Pool & |
| ) | `[virtual]`

| Adds the event to the buffer. When full the buffer is flushed. Implements AppenderSkeleton.

virtual void close | ( |  | ) | `[virtual]`

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

virtual 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).

virtual void execute | ( | const LogString & | sql,
|  | log4cxx::helpers::Pool & | p
| ) | `[protected, virtual]`

| 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.

virtual void flushBuffer | ( | log4cxx::helpers::Pool & | p | ) | `[virtual]`

| 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!

size_t getBufferSize | ( |  | ) | const`[inline]`

virtual SQLHDBC getConnection | ( | log4cxx::helpers::Pool & | p | ) | `[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.

LogString getLogStatement | ( | const spi::LoggingEventPtr & | event,
|  | helpers::Pool & | p
| ) | 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 LogString& getPassword | ( |  | ) | const`[inline]`

const LogString& getSql | ( |  | ) | const`[inline]`

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

const LogString& getURL | ( |  | ) | const`[inline]`

const LogString& getUser | ( |  | ) | const`[inline]`

virtual bool requiresLayout | ( |  | ) | const`[inline, virtual]`

| ODBCAppender requires a layout. Implements Appender.

void setBufferSize | ( | size_t | newBufferSize | ) | `[inline]`

virtual void setOption | ( | const LogString & | option,
|  | const LogString & | value
| ) | `[virtual]`

| Set options. Reimplemented from AppenderSkeleton.

void setPassword | ( | const LogString & | password | ) | `[inline]`

void setSql | ( | const LogString & | s | ) |

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

void setURL | ( | const LogString & | url | ) | `[inline]`

void setUser | ( | const LogString & | user | ) | `[inline]`

## 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 writing 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.

LogString databasePassword `[protected]`

| User to use for default connection handling.

LogString databaseURL `[protected]`

| URL of the DB for default connection handling.

LogString databaseUser `[protected]`

| User to connect as for default connection handling.

SQLHENV env `[protected]`

LogString 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 file:

- odbcappender.h