log4net和C＃扩展方法| 表演

Question

I have written an simple extension that should allow me to call method GetLogger in any class.

static class Log4NetExtension {
    public static ILog GetLogger(this object cls) {
        return LogManager.GetLogger(cls.GetType());
    }
}

So, I can log from different class as follows:

class Test1 {
    public void method() {
        this.GetLogger ().Fatal ("Lorem ipsum no dolor...");
    }
}
class Test2 {
    public void method() {
        this.GetLogger().Error("Lorem ipsum no dolor...");
    }
}

My question is, what exactly LogManager.GetLogger() method call does? Does it creates the logger every time on its method call? Does such approach have a great impact on my application in case I call this.GetLogger() regularly?

Answer 1

This is all based off my assumption but to answer this...

Does it creates the logger every time on its method call?

This logger most likely follows the singleton pattern which will create an instance of itself if it does not exist. Then after this, if any new getLogger call is invoked it will return the active instance. The logger is only created one time.

Does such approach have a great impact on my application in case I call this.GetLogger() regularly?

If the above assumption proves to be true then there should be little to no impact on your program. Most single threaded loggers usually follow the singleton pattern. If you're working with multiple threads then this gets a little more tricky.

Answer 2

According to the Log4net documentation the GetLogger() call will look for a logger with that name (the class name you provide) and only create one if it doesn't exist. That's about the best performance you are going to get - lazy create of the logger only if it hasn't already.