Sends LoggingEvent objects to a set of remote log servers, usually a SocketNode. More...

Inheritance diagram for SocketHubAppender:

Public Member Functions
	SocketHubAppender ()

	~SocketHubAppender ()

	SocketHubAppender (int port)
	Connects to remote server at `address` and `port`. More...

virtual void	activateOptions (log4cxx::helpers::Pool &p)
	Set up the socket server on the specified port. More...

virtual void	setOption (const LogString &option, const LogString &value)
	Set options. More...

virtual void	close ()
	Release any resources allocated within the appender such as file handles, network connections, etc. More...

virtual void	append (const spi::LoggingEventPtr &event, log4cxx::helpers::Pool &p)
	Append an event to all of current connections. More...

virtual bool	requiresLayout () const
	The SocketHubAppender does not use a layout. More...

void	setPort (int port1)
	The Port option takes a positive integer representing the port where the server is waiting for connections. More...

int	getPort () const
	Returns value of the Port option. More...

void	setLocationInfo (bool locationInfo1)
	The LocationInfo option takes a boolean value. More...

bool	getLocationInfo () const
	Returns value of the LocationInfo option. More...

Public Member Functions inherited from AppenderSkeleton
	AppenderSkeleton ()

	AppenderSkeleton (const LayoutPtr &layout)

void	addRef () const

void	releaseRef () const

void	finalize ()
	Finalize this appender by calling the derived class' `close` method. More...

void	addFilter (const spi::FilterPtr &newFilter)
	Add a filter to end of the filter list. More...

void	clearFilters ()
	Clear the filters chain. More...

const spi::ErrorHandlerPtr &	getErrorHandler () const
	Return the currently set spi::ErrorHandler for this Appender. More...

spi::FilterPtr	getFilter () const
	Returns the head Filter. More...

const spi::FilterPtr &	getFirstFilter () const
	Return the first filter in the filter chain for this Appender. More...

LayoutPtr	getLayout () const
	Returns the layout of this appender. More...

LogString	getName () const
	Returns the name of this Appender. More...

const LevelPtr &	getThreshold () const
	Returns this appenders threshold level. More...

bool	isAsSevereAsThreshold (const LevelPtr &level) const
	Check whether the message level is below the appender's threshold. More...

virtual void	doAppend (const spi::LoggingEventPtr &event, log4cxx::helpers::Pool &pool)
	This method performs threshold checks and invokes filters before delegating actual logging to the subclasses specific AppenderSkeleton::append method. More...

void	setErrorHandler (const spi::ErrorHandlerPtr &eh)
	Set the ErrorHandler for this Appender. More...

void	setLayout (const LayoutPtr &layout1)
	Set the layout for this appender. More...

void	setName (const LogString &name1)
	Set the name of this Appender. More...

void	setThreshold (const LevelPtr &threshold)
	Set the threshold level. More...

Public Member Functions inherited from Appender
virtual	~Appender ()

Public Member Functions inherited from OptionHandler
virtual	~OptionHandler ()

Public Member Functions inherited from Object
virtual const helpers::Class &	getClass () const

virtual	~Object ()

virtual bool	instanceof (const Class &clazz) const =0

virtual const void *	cast (const Class &clazz) const =0

Public Member Functions inherited from ObjectImpl
	ObjectImpl ()

virtual	~ObjectImpl ()

void	addRef () const

void	releaseRef () const

Additional Inherited Members
Static Public Member Functions inherited from Object
static const helpers::Class &	getStaticClass ()

static const log4cxx::helpers::ClassRegistration &	registerClass ()

Protected Member Functions inherited from AppenderSkeleton
void	doAppendImpl (const spi::LoggingEventPtr &event, log4cxx::helpers::Pool &pool)

Protected Attributes inherited from AppenderSkeleton
LayoutPtr	layout
	The layout variable does not need to be set if the appender implementation has its own layout. More...

LogString	name
	Appenders are named. More...

LevelPtr	threshold
	There is no level threshold filtering by default. More...

spi::ErrorHandlerPtr	errorHandler
	It is assumed and enforced that errorHandler is never null. More...

spi::FilterPtr	headFilter
	The first filter in the filter chain. More...

spi::FilterPtr	tailFilter
	The last filter in the filter chain. More...

bool	closed
	Is this appender closed? More...

log4cxx::helpers::Pool	pool

SHARED_MUTEX	mutex

Protected Attributes inherited from ObjectImpl
unsigned int volatile	ref

Detailed Description

Sends LoggingEvent objects to a set of remote log servers, usually a SocketNode.

Acts just like SocketAppender except that instead of connecting to a given remote log server, SocketHubAppender accepts connections from the remote log servers as clients. It can accept more than one connection. When a log event is received, the event is sent to the set of currently connected remote log servers. Implemented this way it does not require any update to the configuration file to send data to another remote log server. The remote log server simply connects to the host and port the SocketHubAppender is running on.

The SocketHubAppender does not store events such that the remote side will events that arrived after the establishment of its connection. Once connected, events arrive in order as guaranteed by the TCP protocol.

This implementation borrows heavily from the SocketAppender.

The SocketHubAppender has the following characteristics:

If sent to a SocketNode, logging is non-intrusive as far as the log event is concerned. In other words, the event will be logged with the same time stamp, NDC, location info as if it were logged locally.
SocketHubAppender does not use a layout. It ships a serialized spi::LoggingEvent object to the remote side.
SocketHubAppender relies on the TCP protocol. Consequently, if the remote side is reachable, then log events will eventually arrive at remote client.
If no remote clients are attached, the logging requests are simply dropped.
Logging events are automatically buffered by the native TCP implementation. This means that if the link to remote client is slow but still faster than the rate of (log) event production, the application will not be affected by the slow network connection. However, if the network connection is slower then the rate of event production, then the local application can only progress at the network rate. In particular, if the network link to the the remote client is down, the application will be blocked.

On the other hand, if the network link is up, but the remote client is down, the client will not be blocked when making log requests but the log events will be lost due to client unavailability.

The single remote client case extends to multiple clients connections. The rate of logging will be determined by the slowest link.
If the application hosting the SocketHubAppender exits before the SocketHubAppender is closed either explicitly or subsequent to garbage collection, then there might be untransmitted data in the pipe which might be lost. This is a common problem on Windows based systems.

To avoid lost data, it is usually sufficient to close the SocketHubAppender either explicitly or by calling the LogManager::shutdown method before exiting the application.

Constructor & Destructor Documentation

SocketHubAppender ( )

~SocketHubAppender ( )

SocketHubAppender ( int port )

Connects to remote server at address and port.

Member Function Documentation

virtual void activateOptions ( log4cxx::helpers::Pool & p )

virtual

Set up the socket server on the specified port.

Reimplemented from AppenderSkeleton.

virtual void append	(	const spi::LoggingEventPtr &	event,
		log4cxx::helpers::Pool &	p
	)

virtual

Append an event to all of current connections.

Implements AppenderSkeleton.

virtual void close ( )

virtual

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.

Implements Appender.

bool getLocationInfo ( ) const

inline

Returns value of the LocationInfo option.

int getPort ( ) const

inline

Returns value of the Port option.

virtual bool requiresLayout ( ) const

inlinevirtual

The SocketHubAppender does not use a layout.

Hence, this method returns false.

Implements Appender.

void setLocationInfo ( bool locationInfo1 )

inline

The LocationInfo option takes a boolean value.

If true, the information sent to the remote host will include location information. By default no location information is sent to the server.

virtual void setOption	(	const LogString &	option,
		const LogString &	value
	)

virtual

Set options.

Reimplemented from AppenderSkeleton.

void setPort ( int port1 )

inline

The Port option takes a positive integer representing the port where the server is waiting for connections.

The documentation for this class was generated from the following file:

sockethubappender.h

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation