@Override
    public boolean isErrorEnabled() {
        return delegate().isErrorEnabled();
    }
A logger implementation which logs via a delegate logger. By default, the delegate is a
{@link NOPLogger}. However, a different delegate can be set at any time.

<p>See also the <a href="http://www.slf4j.org/codes.html#substituteLogger">relevant
error code</a> documentation.

@author Chetan Mehrotra
@author Ceki Gulcu
slf4j-api/src/main/java/org/slf4j/helpers/SubstituteLogger.java