DDD_Log.h

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#ifndef DDD_LOG_H_
#define DDD_LOG_H_

/*! \file DDD_Log.h
  

  \par Copyright Information

  Copyright (c) 2012 The DiSTI Corporation.<br>
  11301 Corporate Blvd; Suite 100<br>
  Orlando, Florida 32817<br>
  USA<br>
  <br>
  All rights reserved.<br>

  This Software contains proprietary trade secrets of DiSTI and may not be
reproduced, in whole or part, in any form, or by any means of electronic,
mechanical, or otherwise, without the written permission of DiSTI.  Said
permission may be derived through the purchase of applicable DiSTI product
licenses which detail the distribution rights of this content and any
Derivative Works based on this or other copyrighted DiSTI Software.

  NO WARRANTY. THE SOFTWARE IS PROVIDED "AS-IS," WITHOUT WARRANTY OF ANY KIND,
AND ANY USE OF THIS SOFTWARE PRODUCT IS AT YOUR OWN RISK. TO THE MAXIMUM EXTENT
PERMITTED BY APPLICABLE LAW, DISTI AND ITS SUPPLIERS DISCLAIM ALL WARRANTIES
AND CONDITIONS, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY AND/OR FITNESS FOR A
PARTICULAR PURPOSE, TITLE, AND NON-INFRINGEMENT, WITH REGARD TO THE SOFTWARE.

  LIMITATION OF LIABILITY. TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW,
IN NO EVENT SHALL DISTI OR ITS SUPPLIERS BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
INDIRECT, OR CONSEQUENTIAL DAMAGES WHATSOEVER (INCLUDING, WITHOUT LIMITATION,
DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS
INFORMATION, OR ANY OTHER PECUNIARY LOSS) ARISING OUT OF THE USE OF OR
INABILITY TO USE THE SOFTWARE, EVEN IF DISTI HAS BEEN ADVISED OF THE POSSIBLITY
OF SUCH DAMAGES.  DISTI'S ENTIRE LIABILITY AND YOUR EXCLUSIVE REMEDY SHALL NOT
EXCEED FIVE DOLLARS (US$5.00).

  The aforementioned terms and restrictions are governed by the laws of the
State of Florida and the United States of America.

*/

#include "DDD_Include.h"
#include "dynamic_ptr_array.h"
#include <string>

namespace disti
{

class DDD_LogObserver;

/** \brief  Simple container for log entries. 
  * \note   Members aren't meant to be mutable once instantiated. */
class DDD_EXPORT DDD_LogEntry
{
public:
    /** Level of importance. */
    enum LogLevel
    {
        LOG_DEBUG,
        LOG_INFO,
        LOG_WARNING,
        LOG_ERROR
    };

    /** Constructor. 
      * \param entryStr  The logged entry string
      * \param level     The entry's level of importance
      */
    DDD_LogEntry(const std::string& entryStr, LogLevel level = LOG_INFO);

    /** Entry Level
      * \return entry log level
      */
    LogLevel Level() const { return _level; }

    /** Entry String
      * \return entry string
      */
    std::string EntryStr() const { return _entryStr; }

    /** Static helper for converting Log Level to a string
      * \param level  The logged entry level
      */
    static const char *LogLevelToString(LogLevel level);

private:
    // The reasoning behind not having mutators for these members is that this class's sole purpose
    // is only to conveniently transport these to observers.

    std::string _entryStr;  /**< The log message string */
    LogLevel _level;        /**< The level of the message */
};



/** \brief Central logging class. Handles all of the logic for registering/unregistering observers, accepting log 
  entries, and notifying log observers. */
class DDD_EXPORT DDD_Log
{
public:
    typedef DynamicPtrArray<DDD_LogObserver*> LogObserverList;

    /** Destructor. */
    virtual ~DDD_Log();

    /** Convenient LogEntry() wrapper for logging general information.
      * \param entry  The logged entry string
      */
    void LogDebug(const char* entry);

    /** Convenient LogEntry() wrapper for logging general information.
      * \param entry  The logged entry string
      */
    void LogInfo(const char* entry);

    /** Convenient LogEntry() wrapper for logging warnings.
      * \param entry  The logged entry string
      */
    void LogWarning(const char* entry);

    /** Convenient LogEntry() wrapper for logging errors.
      * \param entry  The logged entry string
      */
    void LogError(const char* entry);

    /** Log Entry to log observers. This method notifies every log observer.
      * \param entry  The logged entry string
      * \param level  The logged entry level
      */
    void LogEntry(const char *entry, DDD_LogEntry::LogLevel level);

    /** Add Log Observer
      * \param observer  Pointer to a LogObserver (must not be NULL)
      */
    void AddObserver( DDD_LogObserver *observer );

    /** Remove Log Observer
      * \param observer  Pointer to a LogObserver
      */
    void RemoveObserver( DDD_LogObserver *observer );

    /** Singleton interface
      * \return reference to static DDD_LogFacade object
      */
    static DDD_Log& Instance();

    /** Shutdown logger; simply clears observers list */
    void Shutdown();

private:
    /** Constructor. This has been made private to enforce singleton interface. */
    DDD_Log();

private:
    LogObserverList _observers;  /**< List of log observers */
};

}  // end of namespace disti

#endif