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https://issues.apache.org/jira/browse/LOGGING-123?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alexander Pogrebnyak updated LOGGING-123:
-----------------------------------------
Attachment: LogLevel.java
More readable version of LogLevel.java
> Add a LogLevel enum with the usual suspects
> (FATAL,ERROR,WARN,INFO,DEBUG,TRACE)
> -------------------------------------------------------------------------------
>
> Key: LOGGING-123
> URL: https://issues.apache.org/jira/browse/LOGGING-123
> Project: Commons Logging
> Issue Type: New Feature
> Environment: N/A
> Reporter: Alexander Pogrebnyak
> Priority: Trivial
> Attachments: LogLevel.java
>
>
> It is sometimes convenient to setup logging level dynamically.
> For example if you implement Command object pattern. Some of the command
> require very detailed in your face logging (say at INFO, or even WARN
> levels), for others DEBUG or even TRACE would do fine.
> With the current methods on Log interface you either have to do it through
> different boolean settings, which quickly lead to a mess.
> More elegant solution is to define a log level object and just examine it
> when doing logging.
> here is the use case
> final static Log LOGGER = ...;
> public class Command
> {
> final LogLevel _log_level;
> public Command ( final boolean is_logging_enabled )
> {
> LogLevel log_level = LogLevel.TRACE;
> if ( is_logging_enabled )
> {
> log_level = LogLevel.INFO;
> }
> if ( ! log_level.isEnabledIn( LOGGER ) )
> {
> log_level = null;
> }
> _log_level = log_level;
> }
> public void doCommand ( )
> {
> if ( _log_level != null )
> {
> _log_level.log( LOGGER, "Running command" );
> }
> }
> }
> The proposed solution is all done through the inversion of control, so it
> does not require to change a single line in org.apache.commons.logging.Log
> interface, although it might be useful to add these 3 methods:
> boolean isEnabledFor ( final LogLevel level );
> void log ( final LogLevel level, final String message );
> void log ( final LogLevel level, final String message, final Throwable t );
> Here is a full listing of proposed LogLevel.java
> ----------START OF LogLevel.java
> package org.apache.commons.logging;
> /**
> * <p>Title: $RCSFile$</p>
> * <p>Description: Declaration of class
> org.apache.commons.logging.LogLevel</p>
> * <p>Last updated: $Id$</p>
> * <p>Created: May 7, 2008</p>
> * @author Alexander S. Pogrebnyak
> * @version $Revision$
> */
> ///@name Imports
> //@{
> //@}
> /**
> * Defines log levels
> *
> * @author Alexander S. Pogrebnyak
> * @version $Revision$
> */
> public final class LogLevel
> {
> ///@name Constants
> //@{
> /**
> * The <code>FATAL</code> level designates very severe error
> * events that will presumably lead the application to abort.
> */
> public final static LogLevel FATAL =
> new LogLevel(
> "FATAL",
> new ILevelHandler ( )
> {
> public boolean isEnabledIn ( final Log logger )
> {
> return logger.isFatalEnabled( );
> }
> public void log (
> final Log logger,
> final Object message
> )
> {
> logger.fatal( message );
> }
> public void log (
> final Log logger,
> final Object message,
> final Throwable t
> )
> {
> logger.fatal( message, t );
> }
> }
> );
> /**
> * The <code>ERROR</code> level designates error events that
> * might still allow the application to continue running.
> */
> public final static LogLevel ERROR =
> new LogLevel(
> "ERROR",
> new ILevelHandler ( )
> {
> public boolean isEnabledIn ( final Log logger )
> {
> return logger.isErrorEnabled( );
> }
> public void log (
> final Log logger,
> final Object message
> )
> {
> logger.error( message );
> }
> public void log (
> final Log logger,
> final Object message,
> final Throwable t
> )
> {
> logger.error( message, t );
> }
> }
> );
> /**
> * The <code>WARN</code> level designates potentially harmful
> * situations.
> */
> public final static LogLevel WARN =
> new LogLevel(
> "WARN",
> new ILevelHandler ( )
> {
> public boolean isEnabledIn ( final Log logger )
> {
> return logger.isWarnEnabled( );
> }
> public void log (
> final Log logger,
> final Object message
> )
> {
> logger.warn( message );
> }
> public void log (
> final Log logger,
> final Object message,
> final Throwable t
> )
> {
> logger.warn( message, t );
> }
> }
> );
> /**
> * The <code>INFO</code> level designates informational messages
> * that highlight the progress of the application at coarse-grained
> * level.
> */
> public final static LogLevel INFO =
> new LogLevel(
> "INFO",
> new ILevelHandler ( )
> {
> public boolean isEnabledIn ( final Log logger )
> {
> return logger.isInfoEnabled( );
> }
> public void log (
> final Log logger,
> final Object message
> )
> {
> logger.info( message );
> }
> public void log (
> final Log logger,
> final Object message,
> final Throwable t
> )
> {
> logger.info( message, t );
> }
> }
> );
> /**
> * The <code>DEBUG</code> level designates fine-grained
> * informational events that are most useful to debug an
> * application.
> */
> public final static LogLevel DEBUG =
> new LogLevel(
> "DEBUG",
> new ILevelHandler ( )
> {
> public boolean isEnabledIn ( final Log logger )
> {
> return logger.isDebugEnabled( );
> }
> public void log (
> final Log logger,
> final Object message
> )
> {
> logger.debug( message );
> }
> public void log (
> final Log logger,
> final Object message,
> final Throwable t
> )
> {
> logger.debug( message, t );
> }
> }
> );
> /**
> * The <code>TRACE</code> level designates finer-grained
> * informational events than the <code>DEBUG</code> level.
> */
> public final static LogLevel TRACE =
> new LogLevel(
> "TRACE",
> new ILevelHandler ( )
> {
> public boolean isEnabledIn ( final Log logger )
> {
> return logger.isTraceEnabled( );
> }
> public void log (
> final Log logger,
> final Object message
> )
> {
> logger.trace( message );
> }
> public void log (
> final Log logger,
> final Object message,
> final Throwable t
> )
> {
> logger.trace( message, t );
> }
> }
> );
> //@}
> ///@name Fields
> //@{
> public final String name;
>
> private final ILevelHandler _level_handler;
>
> //@}
> ///@name Lifetime Management
> //@{
> private LogLevel (
> final String name,
> final ILevelHandler handler
> )
> {
> this.name = name;
>
> _level_handler = handler;
> }
> //@}
> ///@name Accessors
> //@{
> /**
> * @return name of this level
> */
> public String toString ( )
> {
> return name;
> }
> /**
> * <p>Check whether this level is enabled in a given [EMAIL
> PROTECTED] Log}
> * passed as a parameter.</p>
> *
> * @param logger
> *
> * @return boolean True if this level is enabled in
> * <code>logger</code>.
> */
> public boolean isEnabledIn ( final Log logger )
> {
> return _level_handler.isEnabledIn( logger );
> }
> //@}
>
> ///@name Methods
> //@{
> /**
> * <p>Log a message with this log level to a given [EMAIL PROTECTED]
> Log}
> * passed as a parameter.</p>
> *
> * @param logger to where send this message
> * @param message log this message
> */
> public void log (
> final Log logger,
> final Object message
> )
> {
> _level_handler.log( logger, message );
> }
>
> /**
> * <p>Log an error with this log level to a given [EMAIL PROTECTED]
> Log}
> * passed as a parameter.</p>
> *
> * @param logger to where send this message
> * @param message log this message
> * @param t log this cause
> */
> public void log (
> final Log logger,
> final Object message,
> final Throwable t
> )
> {
> _level_handler.log( logger, message, t );
> }
> //@}
>
>
> private static interface ILevelHandler
> {
> boolean isEnabledIn ( final Log logger );
>
> void log (
> final Log logger,
> final Object message
> );
>
> void log (
> final Log logger,
> final Object message,
> final Throwable t
> );
> }
> }
> ----------END OF LogLevel.java
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