JMessageLogger.hh

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#ifndef __JLOGGER__JMESSAGELOGGER__
#define __JLOGGER__JMESSAGELOGGER__

#include <string>

#include "JSystem/JNetwork.hh"
#include "JSystem/JDate.hh"
#include "JLang/JSharedPointer.hh"
#include "JLogger.hh"


/**
 * \file
 * General purpose message reporting.
 * \author mdejong
 */
namespace JLOGGER {}
namespace JPP { using namespace JLOGGER; }

namespace JLOGGER {

  using JSYSTEM::getIPaddress;
  using JSYSTEM::getDateAndTime;
  using JLANG::JSharedPointer;


  /**
   * Message logging tag.
   */
  static const std::string MESSAGE_TAG = std::string("MSG");


  /**
   * Message logger.
   *
   * The class implements the following message functions:
   *
   *  - debug();
   *  - warning();
   *  - error();
   *  - status();
   *  - notice();
   *
   * The argument of these messages is an STL string.\n
   * The message reported consists of <date time> <host name> <process name> <prefix> <message>\n
   * where the prefix is "DEBUG", "WARNING", "ERROR", "STATUS" or "NOTICE".\n
   * A debug level can be specified which is used to filter the message types for reporting.\n
   * The level OFF will cause the message logger to stop reporting any messages.
   *
   * Note that the JXXXStreamer classes can be used for STL ostream compatible message logging
   * (see JMessageStream.hh).
   */
  class JMessageLogger :
    public JLogger
  {
  public:

    enum JLevel_t {
      OFF     = -1,   //!< No logging of messages
      ERROR   = 0,    //!< Error;   always logged
      STATUS  = 0,    //!< Status;  always logged
      WARNING = 1,    //!< Warning
      NOTICE  = 2,    //!< Notice
      DEBUG   = 3     //!< Debug
    };

    typedef  std::string     JMessage_t;


    /**
     * Default constructor.
     */
    JMessageLogger() :
      logger(),
      host  (getIPaddress()),
      name  ("<unknown>")
    {
      setLevel(OFF);
    }


    /**
     * Constructor.
     *
     * \param  __logger     pointer to logger
     * \param  __name       name
     * \param  __level      debug level
     */
    JMessageLogger(JLogger*           __logger,
                   const std::string& __name,
                   const int          __level = ERROR) :
      host  (getIPaddress()),
      name  (__name)
    {
      logger.reset(__logger);

      setLevel(__level);
    }


    /**
     * Reset logger.
     *
     * \param  __logger     pointer to logger
     */
    void reset(JLogger* __logger = NULL)
    {
      logger.reset(__logger);
    }


    /**
     * Get debug level.
     *
     * \return              debug level
     */
    JLevel_t getLevel()
    {
      return level;
    }


    /**
     * Set debug level.
     *
     * \param  __level      debug level
     */
    void setLevel(const int __level)
    {
      if      (__level <  0)
        level = OFF;
      else if (__level == 0)
        level = ERROR;
      else if (__level == 1)
        level = WARNING;
      else
        level = DEBUG;
    }


    /**
     * Set debug level.
     *
     * \param  __level      debug level
     */
    void setLevel(const JLevel_t __level)
    {
      level = __level;
    }


    /**
     * Check validity of logger object.
     *
     * This operator returns the state of the logger object.
     * The object is valid if the logger object is ready for use, else the object is in-valid.
     * In case the object is in-valid, no messages will be reported.
     *
     * \return          true if logger ready for use; else false
     */
    bool is_valid() const
    {
      return logger.is_valid();
    }


    /**
     * Report message.
     *
     * \param  tag     tag
     * \param  message message
     */
    virtual void typeout(const std::string& tag,
                         const std::string& message)
    {
      logger->typeout(tag, message);
    }


#define TYPEOUT(LEVEL, MESSAGE) this->typeout(LEVEL, #LEVEL, MESSAGE)

    void debug  (const JMessage_t& message) { TYPEOUT(DEBUG,   message); }
    void warning(const JMessage_t& message) { TYPEOUT(WARNING, message); }
    void error  (const JMessage_t& message) { TYPEOUT(ERROR,   message); }
    void notice (const JMessage_t& message) { TYPEOUT(NOTICE,  message); }
    void status (const JMessage_t& message) { TYPEOUT(STATUS,  message); }

#undef  TYPEOUT

  protected:
    /**
     * Report message.
     *
     * \param  __level      level
     * \param  __prefix     prefix
     * \param  __message    message
     */
    void typeout(const JLevel_t    __level,
                 const char*       __prefix,
                 const JMessage_t& __message)
    {
      if (is_valid() && __level <= level && !__message.empty()) {

        JMessage_t message;

        message += getDateAndTime();

        message += " ";
        message += host;

        message += " ";
        message += name;

        message += " ";
        message += __prefix;

        message += " ";
        message += __message;

        typeout(MESSAGE_TAG, message);
      }
    }


    JSharedPointer<JLogger> logger;
    std::string  host;
    std::string  name;
    JLevel_t     level;
  };

  /**
   * Thread-safe message logger.
   *
   * This class aims to provide a thread-safe alternative to the JMessageLogger
   * class. Indeed it can transparently replace a JMessageLogger object
   * to be used in multi-thread environment.
   */
  class JMessageLoggerThreadSafe :
    public JMessageLogger
  {
   public:

   /**
     * Default constructor.
     */
    JMessageLoggerThreadSafe() :
      JMessageLogger()
    {}


   /**
     * Constructor.
     *
     * \param  __logger     pointer to logger
     * \param  __name       name
     * \param  __level      debug level
     */
    JMessageLoggerThreadSafe(JLogger*           __logger,
                             const std::string& __name,
                             const int          __level = ERROR) :
      JMessageLogger(__logger, __name, __level)
    {}


    /**
     * Report message.
     *
     * \param  tag     tag
     * \param  message message
     */
    virtual void typeout(const std::string& tag,
                         const std::string& message)
    {
      JSYNCHRONIZATION::JMutex::JScopedLock lock(logger->mutex());
      logger->typeout(tag, message);
    }
  };
}

#endif