logger.h

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/**
 * @file logger.h
 * Header for Base class for 'loggers' that write text messages to log files
 * (see \ref textlogs and class \link Cantera::Logger Logger\endlink).
 */
#ifndef CT_LOGGER_H
#define CT_LOGGER_H

#include "ct_defs.h"

#include <iostream>

namespace Cantera
{

///
/// Base class for 'loggers' that write text messages to log files.
///
/// This class is used to direct log messages to application- or
/// environment-specific output. The default is to simply print
/// the messages to the standard output stream or standard error
/// stream, but classes may be derived from Logger that implement
/// other output options. This is important when Cantera is used
/// in applications that do not display the standard output, such
/// as MATLAB.  The Cantera MATLAB interface derives a class from
/// Logger that implements these methods with MATLAB-specific
/// procedures, insuring that the messages will be passed through
/// to the user. It would also be possible to derive a class that
/// displayed the messages in a pop-up window, or redirected them
/// to a file, etc.
///
/// To install a logger, call function setLogger (global.h / misc.cpp).
///
/// See the files Cantera/python/src/pylogger.h and
/// Cantera/matlab/cantera/private/mllogger.h for examples of
/// deriving logger classes.
/// @ingroup textlogs
///
class Logger
{
public:

    //! Constructor - empty
    Logger() {}

    //! Destructor - empty
    virtual ~Logger() {}

    //! Write a log message.
    /*!
     *  The default behavior is to write to
     *  the standard output. Note that no end-of-line character is
     *  appended to the message, and so if one is desired it must
     *  be included in the string.
     *
     * @param msg      String message to be written to cout
     */
    virtual void write(const std::string& msg) {
        std::cout << msg;
    }

    //! Write an end of line character and flush output.
    /*!
     *  Some systems treat endl and \n differently. The endl
     *  statement causes a flushing of stdout to the screen.
     */
    virtual void writeendl() {
        std::cout << std::endl;
    }

    //! Write an error message and quit.
    /*!
     *  The default behavior is
     *  to write to the standard error stream, and then call
     *  exit(). Note that no end-of-line character is appended to
     *  the message, and so if one is desired it must be included
     *  in the string. Note that this default behavior will
     *  terminate the application Cantera is invoked from (MATLAB,
     *  Excel, etc.) If this is not desired, then derive a class
     *  and reimplement this method.
     *
     * @param msg    Error message to be written to cerr.
     */
    virtual void error(const std::string& msg) {
        std::cerr << msg << std::endl;
        exit(EXIT_FAILURE);
    }
};

}
#endif