How do I make log4j create log files on demand only?

Question

We have a modular application where modules have their own log4j logs (i.e. communication log and error log). The appenders and categories for these are all configured in th

Answer 1

Extend the standard FileAppender class was unsuccessful for me. So I have found an other solution using appenders programmatically to create log files on demand only (and with timestamp in the name file). I have written these two methods :

public void startLog() {
    SimpleDateFormat sdf_long = new SimpleDateFormat("yyyy_MM_dd_HH_mm_ss");
    FileAppender fa = new FileAppender();
    fa.setName("foo");
    fa.setFile(sdf_long.format(new Date()) + ".log");
    fa.setLayout(new PatternLayout("%d{HH:mm:ss.SSS} %m%n"));
    fa.setThreshold(Level.DEBUG);
    fa.setAppend(true);
    fa.activateOptions();
    Logger.getRootLogger().addAppender(fa);
}

public void stopLog() {
    Logger.getRootLogger().getAppender("foo").close();
    Logger.getRootLogger().removeAppender("foo");
}

My log4j.properties file only configures the console appender. When I want to start logging I call the startLog() method. When I want to log in an other file I call stopLog() first and then startLog() method.