Class ConfigurationLogger


  • public class ConfigurationLogger
    extends java.lang.Object

    A class providing basic logging capabilities.

    When reading configuration files in complex scenarios having log output is useful for diagnostic purposes. Therefore, Commons Configuration produces some logging output. As concrete projects have different requirements on the amount and detail of logging, there is a way of configuring logging: All classes derived from AbstractConfiguration can be assigned a logger which is then used for all log statements generated.

    Allowing a logger object to be passed to a configuration creates a direct dependency to a concrete logging framework in the configuration API. This would make it impossible to switch to an alternative logging framework without breaking backwards compatibility. To avoid this, the ConfigurationLogger class is introduced. It is a minimum abstraction over a logging framework offering only very basic logging capabilities. The methods defined in this class are used by configuration implementations to produce their logging statements. Client applications can create specialized instances and pass them to configuration objects without having to deal with a concrete logging framework. It is even possible to create a subclass that uses a completely different logging framework.

    Since:
    2.0
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private org.apache.commons.logging.Log log
      The internal logger.
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected ConfigurationLogger()
      Creates a new, uninitialized instance of ConfigurationLogger.
        ConfigurationLogger​(java.lang.Class<?> logCls)
      Creates a new instance of ConfigurationLogger that uses a logger whose name is derived from the provided class.
        ConfigurationLogger​(java.lang.String loggerName)
      Creates a new instance of ConfigurationLogger that uses the specified logger name.
      (package private) ConfigurationLogger​(org.apache.commons.logging.Log wrapped)
      Creates a new instance of ConfigurationLogger which wraps the specified logger.
    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      private static org.apache.commons.logging.Log createLoggerForClass​(java.lang.Class<?> cls)
      Creates an internal logger for the given class.
      private static org.apache.commons.logging.Log createLoggerForName​(java.lang.String name)
      Creates an internal logger for the given name.
      void debug​(java.lang.String msg)
      Logs the specified message on debug level.
      void error​(java.lang.String msg)
      Logs the specified message on error level.
      void error​(java.lang.String msg, java.lang.Throwable ex)
      Logs the specified exception on error level.
      (package private) org.apache.commons.logging.Log getLog()
      Gets the internal logger.
      void info​(java.lang.String msg)
      Logs the specified message on info level.
      boolean isDebugEnabled()
      Returns a flag whether logging on debug level is enabled.
      boolean isInfoEnabled()
      Returns a flag whether logging on info level is enabled.
      static ConfigurationLogger newDummyLogger()
      Creates a new dummy logger which produces no output.
      void warn​(java.lang.String msg)
      Logs the specified message on warn level.
      void warn​(java.lang.String msg, java.lang.Throwable ex)
      Logs the specified exception on warn level.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • log

        private final org.apache.commons.logging.Log log
        The internal logger.
    • Constructor Detail

      • ConfigurationLogger

        protected ConfigurationLogger()
        Creates a new, uninitialized instance of ConfigurationLogger. This constructor can be used by derived classes that implement their own specific logging mechanism. Such classes must override all methods because the default implementations do not work in this uninitialized state.
      • ConfigurationLogger

        public ConfigurationLogger​(java.lang.Class<?> logCls)
        Creates a new instance of ConfigurationLogger that uses a logger whose name is derived from the provided class.
        Parameters:
        logCls - the class whose name is to be used for logging (must not be null)
        Throws:
        java.lang.IllegalArgumentException - if the logger class is null
      • ConfigurationLogger

        ConfigurationLogger​(org.apache.commons.logging.Log wrapped)
        Creates a new instance of ConfigurationLogger which wraps the specified logger.
        Parameters:
        wrapped - the logger to be wrapped
      • ConfigurationLogger

        public ConfigurationLogger​(java.lang.String loggerName)
        Creates a new instance of ConfigurationLogger that uses the specified logger name.
        Parameters:
        loggerName - the logger name (must not be null)
        Throws:
        java.lang.IllegalArgumentException - if the logger name is null
    • Method Detail

      • createLoggerForClass

        private static org.apache.commons.logging.Log createLoggerForClass​(java.lang.Class<?> cls)
        Creates an internal logger for the given class. Throws an exception if the class is undefined.
        Parameters:
        cls - the logger class
        Returns:
        the logger object
        Throws:
        java.lang.IllegalArgumentException - if the logger class is undefined
      • createLoggerForName

        private static org.apache.commons.logging.Log createLoggerForName​(java.lang.String name)
        Creates an internal logger for the given name. Throws an exception if the name is undefined.
        Parameters:
        name - the name of the logger
        Returns:
        the logger object
        Throws:
        java.lang.IllegalArgumentException - if the logger name is undefined
      • newDummyLogger

        public static ConfigurationLogger newDummyLogger()
        Creates a new dummy logger which produces no output. If such a logger is passed to a configuration object, logging is effectively disabled.
        Returns:
        the new dummy logger
      • debug

        public void debug​(java.lang.String msg)
        Logs the specified message on debug level.
        Parameters:
        msg - the message to be logged
      • error

        public void error​(java.lang.String msg)
        Logs the specified message on error level.
        Parameters:
        msg - the message to be logged
      • error

        public void error​(java.lang.String msg,
                          java.lang.Throwable ex)
        Logs the specified exception on error level.
        Parameters:
        msg - the message to be logged
        ex - the exception to be logged
      • getLog

        org.apache.commons.logging.Log getLog()
        Gets the internal logger.
        Returns:
        the internal logger
      • info

        public void info​(java.lang.String msg)
        Logs the specified message on info level.
        Parameters:
        msg - the message to be logged
      • isDebugEnabled

        public boolean isDebugEnabled()
        Returns a flag whether logging on debug level is enabled.
        Returns:
        true if debug logging is enabled, false otherwise
      • isInfoEnabled

        public boolean isInfoEnabled()
        Returns a flag whether logging on info level is enabled.
        Returns:
        true if debug logging is enabled, false otherwise
      • warn

        public void warn​(java.lang.String msg)
        Logs the specified message on warn level.
        Parameters:
        msg - the message to be logged
      • warn

        public void warn​(java.lang.String msg,
                         java.lang.Throwable ex)
        Logs the specified exception on warn level.
        Parameters:
        msg - the message to be logged
        ex - the exception to be logged