de.fhg.igd.logging
Class LoggerFactory

java.lang.Object
  de.fhg.igd.logging.LoggerFactory

public class LoggerFactory

extends Object

This factory knows how to create new, and dynamically update already deployed Logger objects depending on the currently chosen underlying logging mechanism. getLogger() or getLogger(String) respectively are intended to be called in order to request Logger instances.

Version:

"$Id: LoggerFactory.java 1913 2007-08-08 02:41:53Z jpeters $"

Author:

Matthias Pressfreund

Field Summary

static String	AUTO_LOGGER The identifier for automatic detection of the logging mechanism
protected static List	logger_priorities_ The priority list of underlying logging mechanisms
protected static String	PKG_PREFIX_ The package prefix
static String	PROPERTIES_RESOURCE The factory properties resource file
static String	PROPERTY_LOGGER_PRIORITIES The name of the logger priorities property within the resource file
private static Set	proxies_ The storage for all deployed LoggerProxy objects
protected static Class	wclazz_ The current wrapper class (will be initialized along with LoggingConfiguration)

Constructor Summary

private

LoggerFactory() Hidden unused construction.

Method Summary

protected static void	changeLogger(String logger) Change the underlying logging mechanism and implicitly update all deployed proxies.
protected static void	dismissProxy(LoggerProxy proxy) Remove a proxy from the cache.
private static Class	findWrapperClass(String logger) Find the corresponding Wrapper implementation class for the given underlying logging mechanism.
static Logger	getLogger() Get a ready-to-use groupless logger object.
static Logger	getLogger(String group) Get a ready-to-use logger object with the specified group name.
protected static String	underlyingLoggingMechanism() Get the short name of the underlying logging mechanism (as it is expected in LoggingConfiguration.setLogger(String)) that is currently in use.
protected static void	updateProxies() Update proxies in case a better matching target is available.
private static void	updateProxies(Class wclazz, boolean exchange) Perform an update of proxy targets, either in case of a logger change, when all deployed instances definitely need to be exchanged, or in case a better match may be available.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PROPERTIES_RESOURCE

public static final String PROPERTIES_RESOURCE

The factory properties resource file

See Also:

Constant Field Values

PROPERTY_LOGGER_PRIORITIES

public static final String PROPERTY_LOGGER_PRIORITIES

The name of the logger priorities property within the resource file

See Also:

Constant Field Values

AUTO_LOGGER

public static final String AUTO_LOGGER

The identifier for automatic detection of the logging mechanism

See Also:

Constant Field Values

PKG_PREFIX_

protected static final String PKG_PREFIX_

The package prefix

See Also:

Constant Field Values

proxies_

private static Set proxies_

The storage for all deployed LoggerProxy objects

logger_priorities_

protected static List logger_priorities_

The priority list of underlying logging mechanisms

wclazz_

protected static Class wclazz_

The current wrapper class (will be initialized along with LoggingConfiguration)

Constructor Detail

LoggerFactory

private LoggerFactory()

Hidden unused construction.

Method Detail

getLogger

public static Logger getLogger()

Get a ready-to-use groupless logger object.

Returns:

The groupless logger

getLogger

public static Logger getLogger(String group)

Get a ready-to-use logger object with the specified group name.

Parameters:

group - The logger's group name

Returns:

The logger

Throws:

IllegalArgumentException - if the group is null

underlyingLoggingMechanism

protected static String underlyingLoggingMechanism()

Get the short name of the underlying logging mechanism (as it is expected in LoggingConfiguration.setLogger(String)) that is currently in use.

Returns:

The name of the currently used underlying logging mechanism

updateProxies

protected static void updateProxies()

Update proxies in case a better matching target is available.

updateProxies

private static void updateProxies(Class wclazz,
                                  boolean exchange)

Perform an update of proxy targets, either in case of a logger change, when all deployed instances definitely need to be exchanged, or in case a better match may be available. However, the actual update will not be applied before all new target loggers were successfully created. As soon as the creation of a new target fails, already created targets will be dismissed and the configuration will be left untouched.

Parameters:

wclazz - The currently matching Wrapper class

exchange - true if targets should get exchanged in any case after the underlying logging mechanism has been exchanged, otherwise only if there is a better matching target available

Throws:

LoggingException - in case one of the new targets could not be created

changeLogger

protected static void changeLogger(String logger)

Change the underlying logging mechanism and implicitly update all deployed proxies.

Parameters:

logger - The name of the new underlying logging mechanism

findWrapperClass

private static Class findWrapperClass(String logger)

Find the corresponding Wrapper implementation class for the given underlying logging mechanism.

Parameters:

logger - The name of underlying logging mechanism

Returns:

The Wrapper implemenatation class for the given underlying logging mechanism

Throws:

LoggingException - in case the requested underlying logging mechanism is not available

dismissProxy

protected static void dismissProxy(LoggerProxy proxy)

Remove a proxy from the cache. This method will be called implicitely by whenever the garbage collector calls LoggerProxy.finalize().

Parameters:

proxy - The proxy to be dismissed