org.metawidget.util.LogUtils Maven / Gradle / Ivy
// Metawidget (licensed under LGPL)
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package org.metawidget.util;
import java.text.MessageFormat;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.commons.logging.LogFactory;
/**
* Utilities for working with Logging.
*
* Note: we're not trying to create another logging framework here! We're just trying to
* use Commons Logging where available, and java.util Logging where it's not. Most web containers
* will prefer Commons Logging, but we don't want to have to ship commons-logging.jar with, say, a
* Swing applet.
*
* @author Richard Kennard
*/
public final class LogUtils {
//
// Public statics
//
/**
* Where possible, returns an implementation of Commons Logging. For those applications that do
* not use Commons Logging, returns an implementation of java.util Logging.
*
* In general, Commons Logging is the better choice. However, that introduces a mandatory JAR
* dependency which we want to avoid.
*
* Note: we're not trying to create another logging framework here! We're just trying
* to use Commons Logging where available, and java.util Logging where it's not. Most web
* containers will prefer Commons Logging, but we don't want to have to ship commons-logging.jar
* with, say, a Swing applet.
*/
public static Log getLog( Class clazz ) {
try {
return new CommonsLog( clazz );
} catch ( NoClassDefFoundError e ) {
return new UtilLog( clazz.getName() );
}
}
/**
* Common logging interface.
*
* Note: we're not trying to create another logging framework here! We're just trying
* to use Commons Logging where available, and java.util Logging where it's not. Most web
* containers will prefer Commons Logging, but we don't want to have to ship commons-logging.jar
* with, say, a Swing applet.
*/
public interface Log {
//
// Methods
//
boolean isTraceEnabled();
/**
* Log a trace message.
*
* @param debug
* message to log
* @param arguments
* array of arguments that will be merged into the message using standard
* java.text.MessageFormat notation. As a special case, if the last
* argument is a Throwable but is not referenced in the message, its stack trace
* will be printed
*/
void trace( String trace, Object... arguments );
boolean isDebugEnabled();
/**
* Log a debug message.
*
* @param debug
* message to log
* @param arguments
* array of arguments that will be merged into the message using standard
* java.text.MessageFormat notation. As a special case, if the last
* argument is a Throwable but is not referenced in the message, its stack trace
* will be printed
*/
void debug( String debug, Object... arguments );
boolean isInfoEnabled();
/**
* Log an info message.
*
* @param debug
* message to log
* @param arguments
* array of arguments that will be merged into the message using standard
* java.text.MessageFormat notation. As a special case, if the last
* argument is a Throwable but is not referenced in the message, its stack trace
* will be printed
*/
void info( String info, Object... arguments );
boolean isWarnEnabled();
/**
* Log a warning message.
*
* @param debug
* message to log
* @param arguments
* array of arguments that will be merged into the message using standard
* java.text.MessageFormat notation. As a special case, if the last
* argument is a Throwable but is not referenced in the message, its stack trace
* will be printed
*/
void warn( String warning, Object... arguments );
boolean isErrorEnabled();
/**
* Log an error message.
*
* @param debug
* message to log
* @param arguments
* array of arguments that will be merged into the message using standard
* java.text.MessageFormat notation. As a special case, if the last
* argument is a Throwable but is not referenced in the message, its stack trace
* will be printed
*/
void error( String error, Object... arguments );
}
//
// Private statics
//
/**
* Lightweight field that stores the last message sent to trace. Intended for unit
* tests.
*/
/* package private */static String LAST_TRACE_MESSAGE;
/* package private */static Object[] LAST_TRACE_ARGUMENTS;
/**
* Lightweight field that stores the last message sent to Log.debug. Intended for
* unit tests.
*/
/* package private */static String LAST_DEBUG_MESSAGE;
/* package private */static Object[] LAST_DEBUG_ARGUMENTS;
/**
* Lightweight field that stores the last message sent to Log.info. Intended for
* unit tests.
*/
/* package private */static String LAST_INFO_MESSAGE;
/**
* Lightweight field that stores the last message sent to Log.warn. Intended for
* unit tests.
*/
/* package private */static String LAST_WARN_MESSAGE;
/**
* Lightweight field that stores the last message sent to Log.error. Intended for
* unit tests.
*/
/* package private */static String LAST_ERROR_MESSAGE;
/**
* Logging implementation that uses java.util.Logger.
*/
private static class UtilLog
implements Log {
//
// Private members
//
private Logger mLogger;
//
// Constructor
//
public UtilLog( String logger ) {
mLogger = Logger.getLogger( logger );
}
//
// Public methods
//
public boolean isTraceEnabled() {
return mLogger.isLoggable( Level.FINER );
}
public void trace( String trace, Object... arguments ) {
LAST_TRACE_MESSAGE = log( Level.FINER, trace, arguments );
}
public boolean isDebugEnabled() {
return mLogger.isLoggable( Level.FINE );
}
public void debug( String debug, Object... arguments ) {
LAST_DEBUG_MESSAGE = log( Level.FINE, debug, arguments );
}
public boolean isInfoEnabled() {
return mLogger.isLoggable( Level.INFO );
}
public void info( String info, Object... arguments ) {
LAST_INFO_MESSAGE = log( Level.INFO, info, arguments );
}
public boolean isWarnEnabled() {
return mLogger.isLoggable( Level.WARNING );
}
public void warn( String warning, Object... arguments ) {
LAST_WARN_MESSAGE = log( Level.WARNING, warning, arguments );
}
public boolean isErrorEnabled() {
return mLogger.isLoggable( Level.SEVERE );
}
public void error( String error, Object... arguments ) {
LAST_ERROR_MESSAGE = log( Level.SEVERE, error, arguments );
}
//
// Private methods
//
private String log( Level level, String message, Object... arguments ) {
String logged = message;
if ( mLogger.isLoggable( level ) ) {
// Support fast cases with no arguments
int lastArgument = arguments.length - 1;
if ( lastArgument == -1 ) {
mLogger.log( level, logged );
} else {
// Support cases with an unused Throwable on the end
if ( arguments[lastArgument] instanceof Throwable && message.indexOf( "{" + lastArgument + "}" ) == -1 ) {
if ( lastArgument > 0 ) {
logged = MessageFormat.format( logged, arguments );
}
mLogger.log( level, logged, (Throwable) arguments[lastArgument] );
lastArgument--;
} else {
logged = MessageFormat.format( logged, arguments );
mLogger.log( level, logged );
}
if ( lastArgument != -1 && message.indexOf( "{" + lastArgument + "}" ) == -1 ) {
throw new RuntimeException( "Given " + ( lastArgument + 1 ) + " arguments to log, but no {" + lastArgument + "} in message '" + message + "'" );
}
}
}
return logged;
}
}
/**
* Logging implementation that uses org.apache.commons.logging.Log.
*/
private static class CommonsLog
implements Log {
//
// Private members
//
private org.apache.commons.logging.Log mLog;
//
// Constructor
//
public CommonsLog( Class clazz ) {
mLog = LogFactory.getLog( clazz );
}
//
// Methods
//
public boolean isTraceEnabled() {
return mLog.isTraceEnabled();
}
public void trace( String trace, Object... arguments ) {
String logged = trace;
if ( isTraceEnabled() ) {
int lastArgument = arguments.length - 1;
if ( lastArgument == -1 ) {
mLog.trace( logged );
} else {
if ( arguments[lastArgument] instanceof Throwable && trace.indexOf( "{" + lastArgument + "}" ) == -1 ) {
if ( lastArgument > 0 ) {
logged = MessageFormat.format( logged, arguments );
}
mLog.trace( logged, (Throwable) arguments[lastArgument] );
lastArgument--;
} else {
logged = MessageFormat.format( logged, arguments );
mLog.trace( logged );
}
if ( lastArgument != -1 && trace.indexOf( "{" + lastArgument + "}" ) == -1 ) {
throw new RuntimeException( "Given " + ( lastArgument + 1 ) + " arguments to log, but no {" + lastArgument + "} in message '" + trace + "'" );
}
}
}
LAST_TRACE_MESSAGE = logged;
LAST_TRACE_ARGUMENTS = arguments;
}
public boolean isDebugEnabled() {
return mLog.isDebugEnabled();
}
public void debug( String debug, Object... arguments ) {
String logged = debug;
if ( isDebugEnabled() ) {
int lastArgument = arguments.length - 1;
if ( lastArgument == -1 ) {
mLog.debug( logged );
} else {
if ( arguments[lastArgument] instanceof Throwable && debug.indexOf( "{" + lastArgument + "}" ) == -1 ) {
if ( lastArgument > 0 ) {
logged = MessageFormat.format( logged, arguments );
}
mLog.debug( logged, (Throwable) arguments[lastArgument] );
lastArgument--;
} else {
logged = MessageFormat.format( logged, arguments );
mLog.debug( logged );
}
if ( lastArgument != -1 && debug.indexOf( "{" + lastArgument + "}" ) == -1 ) {
throw new RuntimeException( "Given " + ( lastArgument + 1 ) + " arguments to log, but no {" + lastArgument + "} in message '" + debug + "'" );
}
}
}
LAST_DEBUG_MESSAGE = logged;
LAST_DEBUG_ARGUMENTS = arguments;
}
public boolean isInfoEnabled() {
return mLog.isInfoEnabled();
}
public void info( String info, Object... arguments ) {
String logged = info;
if ( isInfoEnabled() ) {
int lastArgument = arguments.length - 1;
if ( lastArgument == -1 ) {
mLog.info( logged );
} else {
if ( arguments[lastArgument] instanceof Throwable && info.indexOf( "{" + lastArgument + "}" ) == -1 ) {
if ( lastArgument > 0 ) {
logged = MessageFormat.format( logged, arguments );
}
mLog.info( logged, (Throwable) arguments[lastArgument] );
lastArgument--;
} else {
logged = MessageFormat.format( logged, arguments );
mLog.info( logged );
}
if ( lastArgument != -1 && info.indexOf( "{" + lastArgument + "}" ) == -1 ) {
throw new RuntimeException( "Given " + ( lastArgument + 1 ) + " arguments to log, but no {" + lastArgument + "} in message '" + info + "'" );
}
}
}
LAST_INFO_MESSAGE = logged;
}
public boolean isWarnEnabled() {
return mLog.isWarnEnabled();
}
public void warn( String warning, Object... arguments ) {
String logged = warning;
if ( isWarnEnabled() ) {
int lastArgument = arguments.length - 1;
if ( lastArgument == -1 ) {
mLog.warn( logged );
} else {
if ( arguments[lastArgument] instanceof Throwable && warning.indexOf( "{" + lastArgument + "}" ) == -1 ) {
if ( lastArgument > 0 ) {
logged = MessageFormat.format( logged, arguments );
}
mLog.warn( logged, (Throwable) arguments[lastArgument] );
lastArgument--;
} else {
logged = MessageFormat.format( logged, arguments );
mLog.warn( logged );
}
if ( lastArgument != -1 && warning.indexOf( "{" + lastArgument + "}" ) == -1 ) {
throw new RuntimeException( "Given " + ( lastArgument + 1 ) + " arguments to log, but no {" + lastArgument + "} in message '" + warning + "'" );
}
}
}
LAST_WARN_MESSAGE = logged;
}
public boolean isErrorEnabled() {
return mLog.isErrorEnabled();
}
public void error( String error, Object... arguments ) {
if ( !isErrorEnabled() ) {
return;
}
String logged = error;
int lastArgument = arguments.length - 1;
if ( lastArgument == -1 ) {
mLog.error( logged );
} else {
if ( arguments[lastArgument] instanceof Throwable && error.indexOf( "{" + lastArgument + "}" ) == -1 ) {
if ( lastArgument > 0 ) {
logged = MessageFormat.format( logged, arguments );
}
mLog.error( logged, (Throwable) arguments[lastArgument] );
lastArgument--;
} else {
logged = MessageFormat.format( logged, arguments );
mLog.error( logged );
}
if ( lastArgument != -1 && error.indexOf( "{" + lastArgument + "}" ) == -1 ) {
throw new RuntimeException( "Given " + ( lastArgument + 1 ) + " arguments to log, but no {" + lastArgument + "} in message '" + error + "'" );
}
}
LAST_ERROR_MESSAGE = logged;
}
}
//
// Private constructor
//
private LogUtils() {
// Can never be called
}
}