SLF4J API Source Code
SLF4J API is a simple API that allows to plug in any desired logging library
at deployment time.
Here is the source code for SLF4J API 2.0.4. You can download its pre-compiled version slf4j-api-2.0.4.jar at SLF4J Download Website.
✍: FYIcenter.com
⏎ org/slf4j/Logger.java
/**
* Copyright (c) 2004-2022 QOS.ch
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
package org.slf4j;
import static org.slf4j.event.EventConstants.DEBUG_INT;
import static org.slf4j.event.EventConstants.ERROR_INT;
import static org.slf4j.event.EventConstants.INFO_INT;
import static org.slf4j.event.EventConstants.TRACE_INT;
import static org.slf4j.event.EventConstants.WARN_INT;
import static org.slf4j.event.Level.DEBUG;
import static org.slf4j.event.Level.ERROR;
import static org.slf4j.event.Level.INFO;
import static org.slf4j.event.Level.TRACE;
import static org.slf4j.event.Level.WARN;
import org.slf4j.event.Level;
import org.slf4j.helpers.CheckReturnValue;
import org.slf4j.spi.DefaultLoggingEventBuilder;
import org.slf4j.spi.LoggingEventBuilder;
import org.slf4j.spi.NOPLoggingEventBuilder;
/**
* The org.slf4j.Logger interface is the main user entry point of SLF4J API.
* It is expected that logging takes place through concrete implementations
* of this interface.
*
* <H3>Typical usage pattern:</H3>
* <pre>
* import org.slf4j.Logger;
* import org.slf4j.LoggerFactory;
*
* public class Wombat {
*
* <span style="color:green">final static Logger logger = LoggerFactory.getLogger(Wombat.class);</span>
* Integer t;
* Integer oldT;
*
* public void setTemperature(Integer temperature) {
* oldT = t;
* t = temperature;
* <span style="color:green">logger.debug("Temperature set to {}. Old temperature was {}.", t, oldT);</span>
* if (temperature.intValue() > 50) {
* <span style="color:green">logger.info("Temperature has risen above 50 degrees.");</span>
* }
* }
* }
* </pre>
*
* <p>Note that version 2.0 of the SLF4J API introduces a <a href="../../../manual.html#fluent">fluent api</a>,
* the most significant API change to occur in the last 20 years.
*
* <p>Be sure to read the FAQ entry relating to <a href="../../../faq.html#logging_performance">parameterized
* logging</a>. Note that logging statements can be parameterized in
* <a href="../../../faq.html#paramException">presence of an exception/throwable</a>.
*
* <p>Once you are comfortable using loggers, i.e. instances of this interface, consider using
* <a href="MDC.html">MDC</a> as well as <a href="Marker.html">Markers</a>.
*
* @author Ceki Gülcü
*/
public interface Logger {
/**
* Case-insensitive String constant used to retrieve the name of the root logger.
*
* @since 1.3
*/
final public String ROOT_LOGGER_NAME = "ROOT";
/**
* Return the name of this <code>Logger</code> instance.
* @return name of this logger instance
*/
public String getName();
/**
* <p>Make a new {@link LoggingEventBuilder} instance as appropriate for this logger implementation.
* This default implementation always returns a new instance of {@link DefaultLoggingEventBuilder}.</p>
* <p></p>
* <p>This method is intended to be used by logging systems implementing the SLF4J API and <b>not</b>
* by end users.</p>
* <p></p>
* <p>Also note that a {@link LoggingEventBuilder} instance should be built for all levels,
* independently of the level argument. In other words, this method is an <b>unconditional</b>
* constructor for the {@link LoggingEventBuilder} appropriate for this logger implementation.</p>
* <p></p>
* @param level desired level for the event builder
* @return a new {@link LoggingEventBuilder} instance as appropriate for <b>this</b> logger
* @since 2.0
*/
default public LoggingEventBuilder makeLoggingEventBuilder(Level level) {
return new DefaultLoggingEventBuilder(this, level);
}
/**
* Make a new {@link LoggingEventBuilder} instance as appropriate for this logger and the
* desired {@link Level} passed as parameter. If this Logger is disabled for the given Level, then
* a {@link NOPLoggingEventBuilder} is returned.
*
*
* @param level desired level for the event builder
* @return a new {@link LoggingEventBuilder} instance as appropriate for this logger
* @since 2.0
*/
@CheckReturnValue
default public LoggingEventBuilder atLevel(Level level) {
if (isEnabledForLevel(level)) {
return makeLoggingEventBuilder(level);
} else {
return NOPLoggingEventBuilder.singleton();
}
}
/**
* Returns whether this Logger is enabled for a given {@link Level}.
*
* @param level
* @return true if enabled, false otherwise.
*/
default public boolean isEnabledForLevel(Level level) {
int levelInt = level.toInt();
switch (levelInt) {
case (TRACE_INT):
return isTraceEnabled();
case (DEBUG_INT):
return isDebugEnabled();
case (INFO_INT):
return isInfoEnabled();
case (WARN_INT):
return isWarnEnabled();
case (ERROR_INT):
return isErrorEnabled();
default:
throw new IllegalArgumentException("Level [" + level + "] not recognized.");
}
}
/**
* Is the logger instance enabled for the TRACE level?
*
* @return True if this Logger is enabled for the TRACE level,
* false otherwise.
* @since 1.4
*/
public boolean isTraceEnabled();
/**
* Log a message at the TRACE level.
*
* @param msg the message string to be logged
* @since 1.4
*/
public void trace(String msg);
/**
* Log a message at the TRACE level according to the specified format
* and argument.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the TRACE level.
*
* @param format the format string
* @param arg the argument
* @since 1.4
*/
public void trace(String format, Object arg);
/**
* Log a message at the TRACE level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the TRACE level.
*
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
* @since 1.4
*/
public void trace(String format, Object arg1, Object arg2);
/**
* Log a message at the TRACE level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous string concatenation when the logger
* is disabled for the TRACE level. However, this variant incurs the hidden
* (and relatively small) cost of creating an <code>Object[]</code> before invoking the method,
* even if this logger is disabled for TRACE. The variants taking {@link #trace(String, Object) one} and
* {@link #trace(String, Object, Object) two} arguments exist solely in order to avoid this hidden cost.
*
* @param format the format string
* @param arguments a list of 3 or more arguments
* @since 1.4
*/
public void trace(String format, Object... arguments);
/**
* Log an exception (throwable) at the TRACE level with an
* accompanying message.
*
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
* @since 1.4
*/
public void trace(String msg, Throwable t);
/**
* Similar to {@link #isTraceEnabled()} method except that the
* marker data is also taken into account.
*
* @param marker The marker data to take into consideration
* @return True if this Logger is enabled for the TRACE level,
* false otherwise.
*
* @since 1.4
*/
public boolean isTraceEnabled(Marker marker);
/**
* Entry point for fluent-logging for {@link org.slf4j.event.Level#TRACE} level.
*
* @return LoggingEventBuilder instance as appropriate for level TRACE
* @since 2.0
*/
@CheckReturnValue
default public LoggingEventBuilder atTrace() {
if (isTraceEnabled()) {
return makeLoggingEventBuilder(TRACE);
} else {
return NOPLoggingEventBuilder.singleton();
}
}
/**
* Log a message with the specific Marker at the TRACE level.
*
* @param marker the marker data specific to this log statement
* @param msg the message string to be logged
* @since 1.4
*/
public void trace(Marker marker, String msg);
/**
* This method is similar to {@link #trace(String, Object)} method except that the
* marker data is also taken into consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg the argument
* @since 1.4
*/
public void trace(Marker marker, String format, Object arg);
/**
* This method is similar to {@link #trace(String, Object, Object)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
* @since 1.4
*/
public void trace(Marker marker, String format, Object arg1, Object arg2);
/**
* This method is similar to {@link #trace(String, Object...)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param argArray an array of arguments
* @since 1.4
*/
public void trace(Marker marker, String format, Object... argArray);
/**
* This method is similar to {@link #trace(String, Throwable)} method except that the
* marker data is also taken into consideration.
*
* @param marker the marker data specific to this log statement
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
* @since 1.4
*/
public void trace(Marker marker, String msg, Throwable t);
/**
* Is the logger instance enabled for the DEBUG level?
*
* @return True if this Logger is enabled for the DEBUG level,
* false otherwise.
*/
public boolean isDebugEnabled();
/**
* Log a message at the DEBUG level.
*
* @param msg the message string to be logged
*/
public void debug(String msg);
/**
* Log a message at the DEBUG level according to the specified format
* and argument.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the DEBUG level.
*
* @param format the format string
* @param arg the argument
*/
public void debug(String format, Object arg);
/**
* Log a message at the DEBUG level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the DEBUG level.
*
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void debug(String format, Object arg1, Object arg2);
/**
* Log a message at the DEBUG level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous string concatenation when the logger
* is disabled for the DEBUG level. However, this variant incurs the hidden
* (and relatively small) cost of creating an <code>Object[]</code> before invoking the method,
* even if this logger is disabled for DEBUG. The variants taking
* {@link #debug(String, Object) one} and {@link #debug(String, Object, Object) two}
* arguments exist solely in order to avoid this hidden cost.
*
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void debug(String format, Object... arguments);
/**
* Log an exception (throwable) at the DEBUG level with an
* accompanying message.
*
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void debug(String msg, Throwable t);
/**
* Similar to {@link #isDebugEnabled()} method except that the
* marker data is also taken into account.
*
* @param marker The marker data to take into consideration
* @return True if this Logger is enabled for the DEBUG level,
* false otherwise.
*/
public boolean isDebugEnabled(Marker marker);
/**
* Log a message with the specific Marker at the DEBUG level.
*
* @param marker the marker data specific to this log statement
* @param msg the message string to be logged
*/
public void debug(Marker marker, String msg);
/**
* This method is similar to {@link #debug(String, Object)} method except that the
* marker data is also taken into consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg the argument
*/
public void debug(Marker marker, String format, Object arg);
/**
* This method is similar to {@link #debug(String, Object, Object)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void debug(Marker marker, String format, Object arg1, Object arg2);
/**
* This method is similar to {@link #debug(String, Object...)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void debug(Marker marker, String format, Object... arguments);
/**
* This method is similar to {@link #debug(String, Throwable)} method except that the
* marker data is also taken into consideration.
*
* @param marker the marker data specific to this log statement
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void debug(Marker marker, String msg, Throwable t);
/**
* Entry point for fluent-logging for {@link org.slf4j.event.Level#DEBUG} level.
*
* @return LoggingEventBuilder instance as appropriate for level DEBUG
* @since 2.0
*/
@CheckReturnValue
default public LoggingEventBuilder atDebug() {
if (isDebugEnabled()) {
return makeLoggingEventBuilder(DEBUG);
} else {
return NOPLoggingEventBuilder.singleton();
}
}
/**
* Is the logger instance enabled for the INFO level?
*
* @return True if this Logger is enabled for the INFO level,
* false otherwise.
*/
public boolean isInfoEnabled();
/**
* Log a message at the INFO level.
*
* @param msg the message string to be logged
*/
public void info(String msg);
/**
* Log a message at the INFO level according to the specified format
* and argument.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the INFO level.
*
* @param format the format string
* @param arg the argument
*/
public void info(String format, Object arg);
/**
* Log a message at the INFO level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the INFO level.
*
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void info(String format, Object arg1, Object arg2);
/**
* Log a message at the INFO level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous string concatenation when the logger
* is disabled for the INFO level. However, this variant incurs the hidden
* (and relatively small) cost of creating an <code>Object[]</code> before invoking the method,
* even if this logger is disabled for INFO. The variants taking
* {@link #info(String, Object) one} and {@link #info(String, Object, Object) two}
* arguments exist solely in order to avoid this hidden cost.
*
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void info(String format, Object... arguments);
/**
* Log an exception (throwable) at the INFO level with an
* accompanying message.
*
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void info(String msg, Throwable t);
/**
* Similar to {@link #isInfoEnabled()} method except that the marker
* data is also taken into consideration.
*
* @param marker The marker data to take into consideration
* @return true if this Logger is enabled for the INFO level,
* false otherwise.
*/
public boolean isInfoEnabled(Marker marker);
/**
* Log a message with the specific Marker at the INFO level.
*
* @param marker The marker specific to this log statement
* @param msg the message string to be logged
*/
public void info(Marker marker, String msg);
/**
* This method is similar to {@link #info(String, Object)} method except that the
* marker data is also taken into consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg the argument
*/
public void info(Marker marker, String format, Object arg);
/**
* This method is similar to {@link #info(String, Object, Object)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void info(Marker marker, String format, Object arg1, Object arg2);
/**
* This method is similar to {@link #info(String, Object...)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void info(Marker marker, String format, Object... arguments);
/**
* This method is similar to {@link #info(String, Throwable)} method
* except that the marker data is also taken into consideration.
*
* @param marker the marker data for this log statement
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void info(Marker marker, String msg, Throwable t);
/**
* Entry point for fluent-logging for {@link org.slf4j.event.Level#INFO} level.
*
* @return LoggingEventBuilder instance as appropriate for level INFO
* @since 2.0
*/
@CheckReturnValue
default public LoggingEventBuilder atInfo() {
if (isInfoEnabled()) {
return makeLoggingEventBuilder(INFO);
} else {
return NOPLoggingEventBuilder.singleton();
}
}
/**
* Is the logger instance enabled for the WARN level?
*
* @return True if this Logger is enabled for the WARN level,
* false otherwise.
*/
public boolean isWarnEnabled();
/**
* Log a message at the WARN level.
*
* @param msg the message string to be logged
*/
public void warn(String msg);
/**
* Log a message at the WARN level according to the specified format
* and argument.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the WARN level.
*
* @param format the format string
* @param arg the argument
*/
public void warn(String format, Object arg);
/**
* Log a message at the WARN level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous string concatenation when the logger
* is disabled for the WARN level. However, this variant incurs the hidden
* (and relatively small) cost of creating an <code>Object[]</code> before invoking the method,
* even if this logger is disabled for WARN. The variants taking
* {@link #warn(String, Object) one} and {@link #warn(String, Object, Object) two}
* arguments exist solely in order to avoid this hidden cost.
*
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void warn(String format, Object... arguments);
/**
* Log a message at the WARN level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the WARN level.
*
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void warn(String format, Object arg1, Object arg2);
/**
* Log an exception (throwable) at the WARN level with an
* accompanying message.
*
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void warn(String msg, Throwable t);
/**
* Similar to {@link #isWarnEnabled()} method except that the marker
* data is also taken into consideration.
*
* @param marker The marker data to take into consideration
* @return True if this Logger is enabled for the WARN level,
* false otherwise.
*/
public boolean isWarnEnabled(Marker marker);
/**
* Log a message with the specific Marker at the WARN level.
*
* @param marker The marker specific to this log statement
* @param msg the message string to be logged
*/
public void warn(Marker marker, String msg);
/**
* This method is similar to {@link #warn(String, Object)} method except that the
* marker data is also taken into consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg the argument
*/
public void warn(Marker marker, String format, Object arg);
/**
* This method is similar to {@link #warn(String, Object, Object)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void warn(Marker marker, String format, Object arg1, Object arg2);
/**
* This method is similar to {@link #warn(String, Object...)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void warn(Marker marker, String format, Object... arguments);
/**
* This method is similar to {@link #warn(String, Throwable)} method
* except that the marker data is also taken into consideration.
*
* @param marker the marker data for this log statement
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void warn(Marker marker, String msg, Throwable t);
/**
* Entry point for fluent-logging for {@link org.slf4j.event.Level#WARN} level.
*
* @return LoggingEventBuilder instance as appropriate for level WARN
* @since 2.0
*/
@CheckReturnValue
default public LoggingEventBuilder atWarn() {
if (isWarnEnabled()) {
return makeLoggingEventBuilder(WARN);
} else {
return NOPLoggingEventBuilder.singleton();
}
}
/**
* Is the logger instance enabled for the ERROR level?
*
* @return True if this Logger is enabled for the ERROR level,
* false otherwise.
*/
public boolean isErrorEnabled();
/**
* Log a message at the ERROR level.
*
* @param msg the message string to be logged
*/
public void error(String msg);
/**
* Log a message at the ERROR level according to the specified format
* and argument.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the ERROR level.
*
* @param format the format string
* @param arg the argument
*/
public void error(String format, Object arg);
/**
* Log a message at the ERROR level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous object creation when the logger
* is disabled for the ERROR level.
*
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void error(String format, Object arg1, Object arg2);
/**
* Log a message at the ERROR level according to the specified format
* and arguments.
*
* <p>This form avoids superfluous string concatenation when the logger
* is disabled for the ERROR level. However, this variant incurs the hidden
* (and relatively small) cost of creating an <code>Object[]</code> before invoking the method,
* even if this logger is disabled for ERROR. The variants taking
* {@link #error(String, Object) one} and {@link #error(String, Object, Object) two}
* arguments exist solely in order to avoid this hidden cost.
*
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void error(String format, Object... arguments);
/**
* Log an exception (throwable) at the ERROR level with an
* accompanying message.
*
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void error(String msg, Throwable t);
/**
* Similar to {@link #isErrorEnabled()} method except that the
* marker data is also taken into consideration.
*
* @param marker The marker data to take into consideration
* @return True if this Logger is enabled for the ERROR level,
* false otherwise.
*/
public boolean isErrorEnabled(Marker marker);
/**
* Log a message with the specific Marker at the ERROR level.
*
* @param marker The marker specific to this log statement
* @param msg the message string to be logged
*/
public void error(Marker marker, String msg);
/**
* This method is similar to {@link #error(String, Object)} method except that the
* marker data is also taken into consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg the argument
*/
public void error(Marker marker, String format, Object arg);
/**
* This method is similar to {@link #error(String, Object, Object)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arg1 the first argument
* @param arg2 the second argument
*/
public void error(Marker marker, String format, Object arg1, Object arg2);
/**
* This method is similar to {@link #error(String, Object...)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param format the format string
* @param arguments a list of 3 or more arguments
*/
public void error(Marker marker, String format, Object... arguments);
/**
* This method is similar to {@link #error(String, Throwable)}
* method except that the marker data is also taken into
* consideration.
*
* @param marker the marker data specific to this log statement
* @param msg the message accompanying the exception
* @param t the exception (throwable) to log
*/
public void error(Marker marker, String msg, Throwable t);
/**
* Entry point for fluent-logging for {@link org.slf4j.event.Level#ERROR} level.
*
* @return LoggingEventBuilder instance as appropriate for level ERROR
* @since 2.0
*/
@CheckReturnValue
default public LoggingEventBuilder atError() {
if (isErrorEnabled()) {
return makeLoggingEventBuilder(ERROR);
} else {
return NOPLoggingEventBuilder.singleton();
}
}
}
⏎ org/slf4j/Logger.java
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