public final class

NOPLogger

extends Logger
java.lang.Object
   ↳ org.apache.log4j.Category
     ↳ org.apache.log4j.Logger
       ↳ org.apache.log4j.spi.NOPLogger

Class Overview

No-operation implementation of Logger used by NOPLoggerRepository.

Summary

[Expand]
Inherited Fields
From class org.apache.log4j.Category
Public Constructors
NOPLogger(NOPLoggerRepository repo, String name)
Create instance of Logger.
Public Methods
void addAppender(Appender newAppender)
Add newAppender to the list of appenders of this Category instance.
void assertLog(boolean assertion, String msg)
If assertion parameter is false, then logs msg as an error statement.
void callAppenders(LoggingEvent event)
Call the appenders in the hierrachy starting at this.
void debug(Object message, Throwable t)
Log a message object with the DEBUG level including the stack trace of the Throwable t passed as parameter.
void debug(Object message)
Log a message object with the DEBUG level.
void error(Object message)
Log a message object with the ERROR Level.
void error(Object message, Throwable t)
Log a message object with the ERROR level including the stack trace of the Throwable t passed as parameter.
void fatal(Object message)
Log a message object with the FATAL Level.
void fatal(Object message, Throwable t)
Log a message object with the FATAL level including the stack trace of the Throwable t passed as parameter.
Enumeration getAllAppenders()
Get the appenders contained in this category as an Enumeration.
Appender getAppender(String name)
Look for the appender named as name.
Priority getChainedPriority()
This method is deprecated. Please use the the getEffectiveLevel() method instead.
Level getEffectiveLevel()
Starting from this category, search the category hierarchy for a non-null level and return it.
ResourceBundle getResourceBundle()
Return the inherited ResourceBundle for this category.
void info(Object message)
Log a message object with the INFO Level.
void info(Object message, Throwable t)
Log a message object with the INFO level including the stack trace of the Throwable t passed as parameter.
boolean isAttached(Appender appender)
Is the appender passed as parameter attached to this category?
boolean isDebugEnabled()
Check whether this category is enabled for the DEBUG Level.
boolean isEnabledFor(Priority level)
Check whether this category is enabled for a given Level passed as parameter.
boolean isInfoEnabled()
Check whether this category is enabled for the info Level.
boolean isTraceEnabled()
Check whether this category is enabled for the TRACE Level.
void l7dlog(Priority priority, String key, Object[] params, Throwable t)
Log a localized and parameterized message.
void l7dlog(Priority priority, String key, Throwable t)
Log a localized message.
void log(String callerFQCN, Priority level, Object message, Throwable t)
This is the most generic printing method.
void log(Priority priority, Object message, Throwable t)
This generic form is intended to be used by wrappers.
void log(Priority priority, Object message)
This generic form is intended to be used by wrappers.
void removeAllAppenders()
Remove all previously added appenders from this Category instance.
void removeAppender(String name)
Remove the appender with the name passed as parameter form the list of appenders.
void removeAppender(Appender appender)
Remove the appender passed as parameter form the list of appenders.
void setLevel(Level level)
Set the level of this Category.
void setPriority(Priority priority)
This method is deprecated. Please use setLevel(Level) instead.
void setResourceBundle(ResourceBundle bundle)
Set the resource bundle to be used with localized logging methods l7dlog(Priority, String, Throwable) and l7dlog(Priority, String, Object[], Throwable).
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.
void warn(Object message, Throwable t)
Log a message with the WARN level including the stack trace of the Throwable t passed as parameter.
void warn(Object message)
Log a message object with the WARN Level.
[Expand]
Inherited Methods
From class org.apache.log4j.Logger
From class org.apache.log4j.Category
From class java.lang.Object
From interface org.apache.log4j.spi.AppenderAttachable

Public Constructors

public NOPLogger (NOPLoggerRepository repo, String name)

Create instance of Logger.

Parameters
repo repository, may not be null.
name name, may not be null, use "root" for root logger.

Public Methods

public void addAppender (Appender newAppender)

Add newAppender to the list of appenders of this Category instance.

If newAppender is already in the list of appenders, then it won't be added again.

public void assertLog (boolean assertion, String msg)

If assertion parameter is false, then logs msg as an error statement.

The assert method has been renamed to assertLog because assert is a language reserved word in JDK 1.4.

Parameters
msg The message to print if assertion is false.

public void callAppenders (LoggingEvent event)

Call the appenders in the hierrachy starting at this. If no appenders could be found, emit a warning.

This method calls all the appenders inherited from the hierarchy circumventing any evaluation of whether to log or not to log the particular log request.

Parameters
event the event to log.

public void debug (Object message, Throwable t)

Log a message object with the DEBUG level including the stack trace of the Throwable t passed as parameter.

See debug(Object) form for more detailed information.

Parameters
message the message object to log.
t the exception to log, including its stack trace.

public void debug (Object message)

Log a message object with the DEBUG level.

This method first checks if this category is DEBUG enabled by comparing the level of this category with the DEBUG level. If this category is DEBUG enabled, then it converts the message object (passed as parameter) to a string by invoking the appropriate ObjectRenderer. It then proceeds to call all the registered appenders in this category and also higher in the hierarchy depending on the value of the additivity flag.

WARNING Note that passing a Throwable to this method will print the name of the Throwable but no stack trace. To print a stack trace use the debug(Object, Throwable) form instead.

Parameters
message the message object to log.

public void error (Object message)

Log a message object with the ERROR Level.

This method first checks if this category is ERROR enabled by comparing the level of this category with ERROR Level. If this category is ERROR enabled, then it converts the message object passed as parameter to a string by invoking the appropriate ObjectRenderer. It proceeds to call all the registered appenders in this category and also higher in the hierarchy depending on the value of the additivity flag.

WARNING Note that passing a Throwable to this method will print the name of the Throwable but no stack trace. To print a stack trace use the error(Object, Throwable) form instead.

Parameters
message the message object to log

public void error (Object message, Throwable t)

Log a message object with the ERROR level including the stack trace of the Throwable t passed as parameter.

See error(Object) form for more detailed information.

Parameters
message the message object to log.
t the exception to log, including its stack trace.

public void fatal (Object message)

Log a message object with the FATAL Level.

This method first checks if this category is FATAL enabled by comparing the level of this category with FATAL Level. If the category is FATAL enabled, then it converts the message object passed as parameter to a string by invoking the appropriate ObjectRenderer. It proceeds to call all the registered appenders in this category and also higher in the hierarchy depending on the value of the additivity flag.

WARNING Note that passing a Throwable to this method will print the name of the Throwable but no stack trace. To print a stack trace use the fatal(Object, Throwable) form instead.

Parameters
message the message object to log

public void fatal (Object message, Throwable t)

Log a message object with the FATAL level including the stack trace of the Throwable t passed as parameter.

See fatal(Object) for more detailed information.

Parameters
message the message object to log.
t the exception to log, including its stack trace.

public Enumeration getAllAppenders ()

Get the appenders contained in this category as an Enumeration. If no appenders can be found, then a NullEnumeration is returned.

Returns
  • Enumeration An enumeration of the appenders in this category.

public Appender getAppender (String name)

Look for the appender named as name.

Return the appender with that name if in the list. Return null otherwise.

public Priority getChainedPriority ()

This method is deprecated.
Please use the the getEffectiveLevel() method instead.

public Level getEffectiveLevel ()

Starting from this category, search the category hierarchy for a non-null level and return it. Otherwise, return the level of the root category.

The Category class is designed so that this method executes as quickly as possible.

public ResourceBundle getResourceBundle ()

Return the inherited ResourceBundle for this category.

This method walks the hierarchy to find the appropriate resource bundle. It will return the resource bundle attached to the closest ancestor of this category, much like the way priorities are searched. In case there is no bundle in the hierarchy then null is returned.

public void info (Object message)

Log a message object with the INFO Level.

This method first checks if this category is INFO enabled by comparing the level of this category with INFO Level. If the category is INFO enabled, then it converts the message object passed as parameter to a string by invoking the appropriate ObjectRenderer. It proceeds to call all the registered appenders in this category and also higher in the hierarchy depending on the value of the additivity flag.

WARNING Note that passing a Throwable to this method will print the name of the Throwable but no stack trace. To print a stack trace use the info(Object, Throwable) form instead.

Parameters
message the message object to log

public void info (Object message, Throwable t)

Log a message object with the INFO level including the stack trace of the Throwable t passed as parameter.

See info(Object) for more detailed information.

Parameters
message the message object to log.
t the exception to log, including its stack trace.

public boolean isAttached (Appender appender)

Is the appender passed as parameter attached to this category?

public boolean isDebugEnabled ()

Check whether this category is enabled for the DEBUG Level.

This function is intended to lessen the computational cost of disabled log debug statements.

For some cat Category object, when you write, 

      cat.debug("This is entry number: " + i );

You incur the cost constructing the message, concatenatiion in this case, regardless of whether the message is logged or not.

If you are worried about speed, then you should write 

 	 if(cat.isDebugEnabled()) {
 	   cat.debug("This is entry number: " + i );
 	 }

This way you will not incur the cost of parameter construction if debugging is disabled for cat. On the other hand, if the cat is debug enabled, you will incur the cost of evaluating whether the category is debug enabled twice. Once in isDebugEnabled and once in the debug. This is an insignificant overhead since evaluating a category takes about 1%% of the time it takes to actually log.

Returns
  • boolean - true if this category is debug enabled, false otherwise.

public boolean isEnabledFor (Priority level)

Check whether this category is enabled for a given Level passed as parameter. See also isDebugEnabled().

Returns
  • boolean True if this category is enabled for level.

public boolean isInfoEnabled ()

Check whether this category is enabled for the info Level. See also isDebugEnabled().

Returns
  • boolean - true if this category is enabled for level info, false otherwise.

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.

public void l7dlog (Priority priority, String key, Object[] params, Throwable t)

Log a localized and parameterized message. First, the user supplied key is searched in the resource bundle. Next, the resulting pattern is formatted using format(String, Object[]) method with the user supplied object array params.

public void l7dlog (Priority priority, String key, Throwable t)

Log a localized message. The user supplied parameter key is replaced by its localized version from the resource bundle.

public void log (String callerFQCN, Priority level, Object message, Throwable t)

This is the most generic printing method. It is intended to be invoked by wrapper classes.

Parameters
callerFQCN The wrapper class' fully qualified class name.
level The level of the logging request.
message The message of the logging request.
t The throwable of the logging request, may be null.

public void log (Priority priority, Object message, Throwable t)

This generic form is intended to be used by wrappers.

public void log (Priority priority, Object message)

This generic form is intended to be used by wrappers.

public void removeAllAppenders ()

Remove all previously added appenders from this Category instance.

This is useful when re-reading configuration information.

public void removeAppender (String name)

Remove the appender with the name passed as parameter form the list of appenders.

public void removeAppender (Appender appender)

Remove the appender passed as parameter form the list of appenders.

public void setLevel (Level level)

Set the level of this Category. If you are passing any of Level.DEBUG, Level.INFO, Level.WARN, Level.ERROR, Level.FATAL as a parameter, you need to case them as Level.

As in 

    logger.setLevel((Level) Level.DEBUG);

Null values are admitted.

public void setPriority (Priority priority)

This method is deprecated.
Please use setLevel(Level) instead.

Set the level of this Category.

Null values are admitted.

public void setResourceBundle (ResourceBundle bundle)

Set the resource bundle to be used with localized logging methods l7dlog(Priority, String, Throwable) and l7dlog(Priority, String, Object[], Throwable).

public void trace (Object message)

Log a message object with the TRACE level.

Parameters
message the message object to log.

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 debug(Object) form for more detailed information.

Parameters
message the message object to log.
t the exception to log, including its stack trace.

public void warn (Object message, Throwable t)

Log a message with the WARN level including the stack trace of the Throwable t passed as parameter.

See warn(Object) for more detailed information.

Parameters
message the message object to log.
t the exception to log, including its stack trace.

public void warn (Object message)

Log a message object with the WARN Level.

This method first checks if this category is WARN enabled by comparing the level of this category with WARN Level. If the category is WARN enabled, then it converts the message object passed as parameter to a string by invoking the appropriate ObjectRenderer. It proceeds to call all the registered appenders in this category and also higher in the hieararchy depending on the value of the additivity flag.

WARNING Note that passing a Throwable to this method will print the name of the Throwable but no stack trace. To print a stack trace use the warn(Object, Throwable) form instead.

Parameters
message the message object to log.