JMessageStream.hh

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#ifndef __JLOGGER__JMESSAGESTREAM__
#define __JLOGGER__JMESSAGESTREAM__

#include <ostream>
#include <sstream>

#include "JMessageLogger.hh"


/**
 * \file
 * Message reporting compatible with STL output stream operations.
 * \author mdejong
 */
namespace JLOGGER {}
namespace JPP { using namespace JLOGGER; }

namespace JLOGGER {

  /**
   * Message streamer.
   *
   * This class can be used in the same way as the STL ostream operator.\n
   * The actual message is reported on detruction of the object, e.g:
   *
   *   JStreamLogger logger(std::cout);
   *
   *   JDebugStream (logger) << "This is a debug message " << hex << 15;
   *
   * will produce on the terminal:
   *
   *   <tt>"... This is a debug message f"</tt>
   *
   * where <tt>...</tt> stands for the message prefix (see class JMessageLogger).
   * The list of available message streamer classes includes:
   *
   *   - JDebugStream
   *   - JWarningStream
   *   - JErrorStream
   *   - JNoticeStream
   *   - JStatusStream
   */
  class JMessageStream :
    public std::ostringstream
  {
  public:
    /**
     * Appends value to internal buffer.
     *
     * \param  value       value
     * \return             this JMessageStream
     */
    template<class T>
    JMessageStream& operator<<(const T& value)
    {
      static_cast<std::ostringstream&>(*this) << value;

      return *this;
    }

    
    /**
     * Type definition of I/O operator.
     */
    typedef std::ostream& (*io_manip) (std::ostream&);
    

    /**
     * Append I/O manipulator.
     *
     * \param  manip       I/O manipulator
     * \return             this JMessageStream
     */
    JMessageStream& operator<<(io_manip manip)
    { 
      static_cast<std::ostringstream&>(*this) << manip;
      
      return *this;
    }
    
  protected:
    /**
     * Constructor.
     *
     * \param  __logger    message logger
     * \param  __typeout   logger method
     */
    JMessageStream(JMessageLogger&        __logger, 
                   void (JMessageLogger::*__typeout)(const std::string&)) : 
      std::ostringstream(),
      logger (__logger),
      typeout(__typeout)
    {}
    

    /**
     * Report message.
     */
    ~JMessageStream()
    {
      (logger.*typeout)(this->str());
    }
    

    JMessageLogger&        logger;
    void (JMessageLogger::*typeout)(const std::string&);
  };


  /**
   * Level specific message streamers.
   */
  struct JDebugStream   : JMessageStream { JDebugStream  (JMessageLogger& logger) : JMessageStream(logger, &JMessageLogger::debug)   {} };
  struct JWarningStream : JMessageStream { JWarningStream(JMessageLogger& logger) : JMessageStream(logger, &JMessageLogger::warning) {} };
  struct JErrorStream   : JMessageStream { JErrorStream  (JMessageLogger& logger) : JMessageStream(logger, &JMessageLogger::error)   {} };
  struct JNoticeStream  : JMessageStream { JNoticeStream (JMessageLogger& logger) : JMessageStream(logger, &JMessageLogger::notice)  {} };
  struct JStatusStream  : JMessageStream { JStatusStream (JMessageLogger& logger) : JMessageStream(logger, &JMessageLogger::status)  {} };
}

#endif