Class SimpleLogger

  • All Implemented Interfaces:
    Serializable, Logger

    public class SimpleLogger
    extends MarkerIgnoringBase

    Simple implementation of Logger that sends all enabled log messages, for all defined loggers, to the console (System.err). The following system properties are supported to configure the behavior of this logger:

    • org.slf4j.simpleLogger.logFile - The output target which can be the path to a file, or the special values "System.out" and "System.err". Default is "System.err".
    • org.slf4j.simpleLogger.cacheOutputStream - If the output target is set to "System.out" or "System.err" (see preceding entry), by default, logs will be output to the latest value referenced by System.out/err variables. By setting this parameter to true, the output stream will be cached, i.e. assigned once at initialization time and re-used independently of the current value referenced by System.out/err.
    • org.slf4j.simpleLogger.defaultLogLevel - Default log level for all instances of SimpleLogger. Must be one of ("trace", "debug", "info", "warn", "error" or "off"). If not specified, defaults to "info".
    • org.slf4j.simpleLogger.log.a.b.c - Logging detail level for a SimpleLogger instance named "a.b.c". Right-side value must be one of "trace", "debug", "info", "warn", "error" or "off". When a SimpleLogger named "a.b.c" is initialized, its level is assigned from this property. If unspecified, the level of nearest parent logger will be used, and if none is set, then the value specified by org.slf4j.simpleLogger.defaultLogLevel will be used.
    • org.slf4j.simpleLogger.showDateTime - Set to true if you want the current date and time to be included in output messages. Default is false
    • org.slf4j.simpleLogger.dateTimeFormat - The date and time format to be used in the output messages. The pattern describing the date and time format is defined by SimpleDateFormat. If the format is not specified or is invalid, the number of milliseconds since start up will be output.
    • org.slf4j.simpleLogger.showThreadName -Set to true if you want to output the current thread name. Defaults to true.
    • org.slf4j.simpleLogger.showLogName - Set to true if you want the Logger instance name to be included in output messages. Defaults to true.
    • org.slf4j.simpleLogger.showShortLogName - Set to true if you want the last component of the name to be included in output messages. Defaults to false.
    • org.slf4j.simpleLogger.levelInBrackets - Should the level string be output in brackets? Defaults to false.
    • org.slf4j.simpleLogger.warnLevelString - The string value output for the warn level. Defaults to WARN.

    In addition to looking for system properties with the names specified above, this implementation also checks for a class loader resource named "simplelogger.properties", and includes any matching definitions from this resource (if it exists).

    With no configuration, the default output includes the relative time in milliseconds, thread name, the level, logger name, and the message followed by the line separator for the host. In log4j terms it amounts to the "%r [%t] %level %logger - %m%n" pattern.

    Sample output follows.

     176 [main] INFO examples.Sort - Populating an array of 2 elements in reverse order.
     225 [main] INFO examples.SortAlgo - Entered the sort method.
     304 [main] INFO examples.SortAlgo - Dump of integer array:
     317 [main] INFO examples.SortAlgo - Element [0] = 0
     331 [main] INFO examples.SortAlgo - Element [1] = 1
     343 [main] INFO examples.Sort - The next log statement should be an error message.
     346 [main] ERROR examples.SortAlgo - Tried to dump an uninitialized array.
       at org.log4j.examples.SortAlgo.dump(SortAlgo.java:58)
       at org.log4j.examples.Sort.main(Sort.java:64)
     467 [main] INFO  examples.Sort - Exiting main method.
     

    This implementation is heavily inspired by Apache Commons Logging's SimpleLog.

    Author:
    Ceki Gülcü, Scott Sanders, Rod Waldhoff, Robert Burrell Donkin, Cédrik LIME
    See Also:
    Serialized Form
    • Method Detail

      • isLevelEnabled

        protected boolean isLevelEnabled​(int logLevel)
        Is the given log level currently enabled?
        Parameters:
        logLevel - is this level enabled?
        Returns:
        whether the logger is enabled for the given level
      • isTraceEnabled

        public boolean isTraceEnabled()
        Are trace messages currently enabled?
        Returns:
        True if this Logger is enabled for the TRACE level, false otherwise.
      • trace

        public void trace​(String msg)
        A simple implementation which logs messages of level TRACE according to the format outlined above.
        Parameters:
        msg - the message string to be logged
      • trace

        public void trace​(String format,
                          Object param1)
        Perform single parameter substitution before logging the message of level TRACE according to the format outlined above.
        Parameters:
        format - the format string
        param1 - the argument
      • trace

        public void trace​(String format,
                          Object param1,
                          Object param2)
        Perform double parameter substitution before logging the message of level TRACE according to the format outlined above.
        Parameters:
        format - the format string
        param1 - the first argument
        param2 - the second argument
      • trace

        public void trace​(String format,
                          Object... argArray)
        Perform double parameter substitution before logging the message of level TRACE according to the format outlined above.
        Parameters:
        format - the format string
        argArray - a list of 3 or more arguments
      • trace

        public void trace​(String msg,
                          Throwable t)
        Log a message of level TRACE, including an exception.
        Parameters:
        msg - the message accompanying the exception
        t - the exception (throwable) to log
      • isDebugEnabled

        public boolean isDebugEnabled()
        Are debug messages currently enabled?
        Returns:
        True if this Logger is enabled for the DEBUG level, false otherwise.
      • debug

        public void debug​(String msg)
        A simple implementation which logs messages of level DEBUG according to the format outlined above.
        Parameters:
        msg - the message string to be logged
      • debug

        public void debug​(String format,
                          Object param1)
        Perform single parameter substitution before logging the message of level DEBUG according to the format outlined above.
        Parameters:
        format - the format string
        param1 - the argument
      • debug

        public void debug​(String format,
                          Object param1,
                          Object param2)
        Perform double parameter substitution before logging the message of level DEBUG according to the format outlined above.
        Parameters:
        format - the format string
        param1 - the first argument
        param2 - the second argument
      • debug

        public void debug​(String format,
                          Object... argArray)
        Perform double parameter substitution before logging the message of level DEBUG according to the format outlined above.
        Parameters:
        format - the format string
        argArray - a list of 3 or more arguments
      • debug

        public void debug​(String msg,
                          Throwable t)
        Log a message of level DEBUG, including an exception.
        Parameters:
        msg - the message accompanying the exception
        t - the exception (throwable) to log
      • isInfoEnabled

        public boolean isInfoEnabled()
        Are info messages currently enabled?
        Returns:
        True if this Logger is enabled for the INFO level, false otherwise.
      • info

        public void info​(String msg)
        A simple implementation which logs messages of level INFO according to the format outlined above.
        Parameters:
        msg - the message string to be logged
      • info

        public void info​(String format,
                         Object arg)
        Perform single parameter substitution before logging the message of level INFO according to the format outlined above.
        Parameters:
        format - the format string
        arg - the argument
      • info

        public void info​(String format,
                         Object arg1,
                         Object arg2)
        Perform double parameter substitution before logging the message of level INFO according to the format outlined above.
        Parameters:
        format - the format string
        arg1 - the first argument
        arg2 - the second argument
      • info

        public void info​(String format,
                         Object... argArray)
        Perform double parameter substitution before logging the message of level INFO according to the format outlined above.
        Parameters:
        format - the format string
        argArray - a list of 3 or more arguments
      • info

        public void info​(String msg,
                         Throwable t)
        Log a message of level INFO, including an exception.
        Parameters:
        msg - the message accompanying the exception
        t - the exception (throwable) to log
      • isWarnEnabled

        public boolean isWarnEnabled()
        Are warn messages currently enabled?
        Returns:
        True if this Logger is enabled for the WARN level, false otherwise.
      • warn

        public void warn​(String msg)
        A simple implementation which always logs messages of level WARN according to the format outlined above.
        Parameters:
        msg - the message string to be logged
      • warn

        public void warn​(String format,
                         Object arg)
        Perform single parameter substitution before logging the message of level WARN according to the format outlined above.
        Parameters:
        format - the format string
        arg - the argument
      • warn

        public void warn​(String format,
                         Object arg1,
                         Object arg2)
        Perform double parameter substitution before logging the message of level WARN according to the format outlined above.
        Parameters:
        format - the format string
        arg1 - the first argument
        arg2 - the second argument
      • warn

        public void warn​(String format,
                         Object... argArray)
        Perform double parameter substitution before logging the message of level WARN according to the format outlined above.
        Parameters:
        format - the format string
        argArray - a list of 3 or more arguments
      • warn

        public void warn​(String msg,
                         Throwable t)
        Log a message of level WARN, including an exception.
        Parameters:
        msg - the message accompanying the exception
        t - the exception (throwable) to log
      • isErrorEnabled

        public boolean isErrorEnabled()
        Are error messages currently enabled?
        Returns:
        True if this Logger is enabled for the ERROR level, false otherwise.
      • error

        public void error​(String msg)
        A simple implementation which always logs messages of level ERROR according to the format outlined above.
        Parameters:
        msg - the message string to be logged
      • error

        public void error​(String format,
                          Object arg)
        Perform single parameter substitution before logging the message of level ERROR according to the format outlined above.
        Parameters:
        format - the format string
        arg - the argument
      • error

        public void error​(String format,
                          Object arg1,
                          Object arg2)
        Perform double parameter substitution before logging the message of level ERROR according to the format outlined above.
        Parameters:
        format - the format string
        arg1 - the first argument
        arg2 - the second argument
      • error

        public void error​(String format,
                          Object... argArray)
        Perform double parameter substitution before logging the message of level ERROR according to the format outlined above.
        Parameters:
        format - the format string
        argArray - a list of 3 or more arguments
      • error

        public void error​(String msg,
                          Throwable t)
        Log a message of level ERROR, including an exception.
        Parameters:
        msg - the message accompanying the exception
        t - the exception (throwable) to log
      • getName

        public String getName()
        Description copied from interface: Logger
        Return the name of this Logger instance.
        Specified by:
        getName in interface Logger
        Returns:
        name of this logger instance
      • readResolve

        protected Object readResolve()
                              throws ObjectStreamException
        Replace this instance with a homonymous (same name) logger returned by LoggerFactory. Note that this method is only called during deserialization.

        This approach will work well if the desired ILoggerFactory is the one references by LoggerFactory. However, if the user manages its logger hierarchy through a different (non-static) mechanism, e.g. dependency injection, then this approach would be mostly counterproductive.

        Returns:
        logger with same name as returned by LoggerFactory
        Throws:
        ObjectStreamException