org.apache.log4j
Class Logger

java.lang.Object
  org.apache.log4j.Category
      org.apache.log4j.Logger

All Implemented Interfaces:

AppenderAttachable

Direct Known Subclasses:

NOPLogger, RootCategory, RootLogger

public class Logger
extends Category

This is the central class in the log4j package. Most logging operations, except configuration, are done through this class.

Since:

log4j 1.2

Author:

Ceki Gülcü

Field Summary

Fields inherited from class org.apache.log4j.Category

additive, level, name, parent, repository, resourceBundle

Constructor Summary

protected

Logger(String name)

Method Summary

static Logger	getLogger(Class clazz) Shorthand for getLogger(clazz.getName()).
static Logger	getLogger(String name) Retrieve a logger named according to the value of the name parameter.
static Logger	getLogger(String name, LoggerFactory factory) Like getLogger(String) except that the type of logger instantiated depends on the type returned by the LoggerFactory.makeNewLoggerInstance(java.lang.String) method of the factory parameter.
static Logger	getRootLogger() Return the root logger for the current logger repository.
boolean	isTraceEnabled() Check whether this category is enabled for the TRACE Level.
void	trace(Object message) Log a message object with the TRACE level.
void	trace(Object message, Throwable t) Log a message object with the TRACE level including the stack trace of the Throwablet passed as parameter.

Methods inherited from class org.apache.log4j.Category

addAppender, assertLog, callAppenders, debug, debug, error, error, exists, fatal, fatal, forcedLog, getAdditivity, getAllAppenders, getAppender, getChainedPriority, getCurrentCategories, getDefaultHierarchy, getEffectiveLevel, getHierarchy, getInstance, getInstance, getLevel, getLoggerRepository, getName, getParent, getPriority, getResourceBundle, getResourceBundleString, getRoot, info, info, isAttached, isDebugEnabled, isEnabledFor, isInfoEnabled, l7dlog, l7dlog, log, log, log, removeAllAppenders, removeAppender, removeAppender, setAdditivity, setLevel, setPriority, setResourceBundle, shutdown, warn, warn

Methods inherited from class java.lang.Object

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

Constructor Detail

Logger

protected Logger(String name)

Method Detail

getLogger

public static Logger getLogger(String name)

Retrieve a logger named according to the value of the name parameter. If the named logger already exists, then the existing instance will be returned. Otherwise, a new instance is created.

By default, loggers do not have a set level but inherit it from their neareast ancestor with a set level. This is one of the central features of log4j.

Parameters:

name - The name of the logger to retrieve.

getLogger

public static Logger getLogger(Class clazz)

Shorthand for getLogger(clazz.getName()).

Parameters:

clazz - The name of clazz will be used as the name of the logger to retrieve. See getLogger(String) for more detailed information.

getRootLogger

public static Logger getRootLogger()

Return the root logger for the current logger repository.

The Logger.getName() method for the root logger always returns stirng value: "root". However, calling Logger.getLogger("root") does not retrieve the root logger but a logger just under root named "root".

In other words, calling this method is the only way to retrieve the root logger.

getLogger

public static Logger getLogger(String name,
                               LoggerFactory factory)

Like getLogger(String) except that the type of logger instantiated depends on the type returned by the LoggerFactory.makeNewLoggerInstance(java.lang.String) method of the factory parameter.

This method is intended to be used by sub-classes.

Parameters:

name - The name of the logger to retrieve.

factory - A LoggerFactory implementation that will actually create a new Instance.

Since:

0.8.5

trace

public void trace(Object message)

Log a message object with the TRACE level.

Parameters:

message - the message object to log.

Since:

1.2.12

See Also:

for an explanation of the logic applied.

trace

public void trace(Object message,
                  Throwable t)

Log a message object with the TRACE level including the stack trace of the Throwablet passed as parameter.

See Category.debug(Object) form for more detailed information.

Parameters:

message - the message object to log.

t - the exception to log, including its stack trace.

Since:

1.2.12

isTraceEnabled

public boolean isTraceEnabled()

Check whether this category is enabled for the TRACE Level.

Returns:

boolean - true if this category is enabled for level TRACE, false otherwise.

Since:

1.2.12