Main BLOGGER: A non-trivial log4cxx tutorial

Monday, September 26, 2005

A non-trivial log4cxx tutorial

Here we only discuss how to change the log4cxx properties on the fly.

1. Traverse current loggers list


    LoggerList curLoggerList;
    curLoggerList =  Logger::getRootLogger()->getLoggerRepository()->getCurrentLoggers();
    LoggerList::iterator i;
    i = curLoggerList.begin();
    while (i!=curLoggerList.end())
    {
        i->p->setLevel(log4cxx::Level::DEBUG); //i->p is the LoggerPtr
        i++;
    }                                     
    Logger::getRootLogger()->setLevel(log4cxx::Level::DEBUG);

2. create Layout, Appender and change conversion pattern on the fly


    static const char patternOne[] = "%r [%t] %-5p %c- %m%n %x%n";
    //create PatternLayout with pattern patternOne

    PatternLayoutPtr myLayoutPtr;
    ConsoleAppenderPtr myConsoleAppenderPtr;

    ACE_NEW_RETURN(myLayoutPtr, PatternLayout, -1);
    myLayoutPtr->setConversionPattern(patternOne); 

    //create ConsoleAppender with layout myLayoutPtr
    ACE_NEW_RETURN(myConsoleAppenderPtr, ConsoleAppender, -1);
    myConsoleAppenderPtr->setLayout(myLayoutPtr);

3. Create FileAppender on the fly


    typedef log4cxx::helpers::ObjectPtrT 
       RollingFileAppenderPtr;

    RollingFileAppenderPtr myRollingFileAppenderPtr;

    LoggerPtr rootLogger = Logger::getRootLogger();
    
    ACE_NEW_RETURN(myRollingFileAppenderPtr, RollingFileAppender, -1); 
    
    myRollingFileAppenderPtr->setFile("myLogFile_server.log");
    myRollingFileAppenderPtr->setMaxBackupIndex( 10 );
    myRollingFileAppenderPtr->setMaxFileSize( "10MB" );
    myRollingFileAppenderPtr->setLayout(myFileLayoutPtr);
    myRollingFileAppenderPtr->activateOptions();
    rootLogger->addAppender( myRollingFileAppenderPtr );

4. Use NDC


    char hostname [MAXHOSTNAMELEN+1];
    ACE_OS::hostname (hostname, sizeof (hostname));
    int port = 8888;

    { //since we need to clean the content in oss, we set it as local
       log4cxx::StringBuffer oss;
       oss << "[" << hostname << ":" << port << "]" << 
           __FILE__ <<  ":" << __LINE__ << "\n"; 
       log4cxx::NDC::push(oss.str());
    }
    LOG4CXX_DEBUG(rootLogger, _T("starting blocking connect"));
    log4cxx::NDC::pop();

- posted by Pop @ 5:31 PM

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