Package org.apache.logging.log4j.jul
Class Log4jBridgeHandler
- java.lang.Object
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- java.util.logging.Handler
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- org.apache.logging.log4j.jul.Log4jBridgeHandler
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- All Implemented Interfaces:
java.beans.PropertyChangeListener
,java.util.EventListener
public class Log4jBridgeHandler extends java.util.logging.Handler implements java.beans.PropertyChangeListener
Bridge from JUL to log4j2.
This is an alternative to log4j.jul.LogManager (running as complete JUL replacement), especially useful for webapps running on a container for which the LogManager cannot or should not be used.
Installation/usage:- Declaratively inside JUL's
logging.properties
:
handlers = org.apache.logging.log4j.jul.Log4jBridgeHandler
(and typically also:org.apache.logging.log4j.jul.Log4jBridgeHandler.propagateLevels = true
)
Note: in a webapp running on Tomcat, you may create aWEB-INF/classes/logging.properties
file to configure JUL for this webapp only: configured handlers and log levels affect your webapp only! This file is then the complete JUL configuration, so JUL's defaults (e.g. log level INFO) apply for stuff not explicitly defined therein. - Programmatically by calling
install()
method, e.g. inside ServletContextListener static-class-init. or contextInitialized()
logging.properties
):- Log4jBridgeHandler.
suffixToAppend
String, suffix to append to JUL logger names, to easily recognize bridged log messages. A dot "." is automatically prepended, so configuration for the basis logger is used
Example:Log4jBridgeHandler.suffixToAppend = _JUL
Useful, for example, if you use JSF because it logs exceptions and throws them afterwards; you can easily recognize the duplicates with this (or concentrate on the non-JUL-logs). - Log4jBridgeHandler.
propagateLevels
boolean, "true" to automatically propagate log4j log levels to JUL. - Log4jBridgeHandler.
sysoutDebug
boolean, perform some (developer) debug output to sysout
LevelTranslator
, see also log4j doc.
Restrictions:- Manually given source/location info in JUL (e.g. entering(), exiting(), throwing(), logp(), logrb() ) will NOT be considered, i.e. gets lost in log4j logging.
- Log levels of JUL have to be adjusted according to log4j log levels: Either by using "propagateLevels" (preferred), or manually by specifying them explicitly, i.e. logging.properties and log4j2.xml have some redundancies.
- Only JUL log events that are allowed according to the JUL log level get to this handler and thus to log4j.
This is only relevant and important if you NOT use "propagateLevels".
If you set
.level = SEVERE
only error logs will be seen by this handler and thus log4j - even if the corresponding log4j log level is ALL.
On the other side, you should NOT set.level = FINER or FINEST
if the log4j level is higher. In this case a lot of JUL log events would be generated, sent via this bridge to log4j and thrown away by the latter.
Note: JUL's default log level (i.e. none specified in logger.properties) is INFO.
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Field Summary
Fields Modifier and Type Field Description private boolean
doDebugOutput
private static java.lang.String
FQCN
private static java.util.logging.Formatter
julFormatter
private java.util.Set<java.util.logging.Logger>
julLoggerRefs
Save "hard" references to configured JUL loggers.private java.lang.String
julSuffixToAppend
private static Logger
SLOGGER
private static java.lang.String
UNKNOWN_LOGGER_NAME
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Constructor Summary
Constructors Constructor Description Log4jBridgeHandler()
Initialize this handler by reading out JUL configuration.Log4jBridgeHandler(boolean debugOutput, java.lang.String suffixToAppend, boolean propagateLevels)
Initialize this handler with given configuration.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
void
flush()
private static java.util.logging.Logger
getJulRootLogger()
private Logger
getLog4jLogger(java.util.logging.LogRecord record)
Return the log4j-Logger instance that will be used for logging.protected void
init(boolean debugOutput, java.lang.String suffixToAppend, boolean propagateLevels)
Perform init.static void
install(boolean removeHandlersForRootLogger, java.lang.String suffixToAppend, boolean propagateLevels)
Adds a new Log4jBridgeHandler instance to JUL's root logger.private void
propagateLogLevels(Configuration config)
Perform developer tests? (Should be unused/outcommented for real code)void
propertyChange(java.beans.PropertyChangeEvent evt)
void
publish(java.util.logging.LogRecord record)
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Field Detail
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SLOGGER
private static final Logger SLOGGER
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FQCN
private static final java.lang.String FQCN
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UNKNOWN_LOGGER_NAME
private static final java.lang.String UNKNOWN_LOGGER_NAME
- See Also:
- Constant Field Values
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julFormatter
private static final java.util.logging.Formatter julFormatter
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doDebugOutput
private boolean doDebugOutput
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julSuffixToAppend
private java.lang.String julSuffixToAppend
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julLoggerRefs
private java.util.Set<java.util.logging.Logger> julLoggerRefs
Save "hard" references to configured JUL loggers. (is lazy init.)
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Method Detail
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install
public static void install(boolean removeHandlersForRootLogger, java.lang.String suffixToAppend, boolean propagateLevels)
Adds a new Log4jBridgeHandler instance to JUL's root logger. This is a programmatic alternative to specifyhandlers = org.apache.logging.log4j.jul.Log4jBridgeHandler
and its configuration in logging.properties.- Parameters:
removeHandlersForRootLogger
- true to remove all other installed handlers on JUL root level
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getJulRootLogger
private static java.util.logging.Logger getJulRootLogger()
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init
protected void init(boolean debugOutput, java.lang.String suffixToAppend, boolean propagateLevels)
Perform init. of this handler with given configuration (typical use is for constructor).
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close
public void close()
- Specified by:
close
in classjava.util.logging.Handler
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publish
public void publish(java.util.logging.LogRecord record)
- Specified by:
publish
in classjava.util.logging.Handler
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flush
public void flush()
- Specified by:
flush
in classjava.util.logging.Handler
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getLog4jLogger
private Logger getLog4jLogger(java.util.logging.LogRecord record)
Return the log4j-Logger instance that will be used for logging. Handles null name case and appends configured suffix.
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propertyChange
public void propertyChange(java.beans.PropertyChangeEvent evt)
- Specified by:
propertyChange
in interfacejava.beans.PropertyChangeListener
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propagateLogLevels
private void propagateLogLevels(Configuration config)
Perform developer tests? (Should be unused/outcommented for real code)
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