Log4JLogger Class — netty Architecture

Source Code

common/src/main/java/io/netty/util/internal/logging/Log4JLogger.java lines 49–597

class Log4JLogger extends AbstractInternalLogger {

    private static final long serialVersionUID = 2851357342488183058L;

    private final transient Logger logger;

    /**
     * Following the pattern discussed in pages 162 through 168 of "The complete
     * log4j manual".
     */
    static final String FQCN = Log4JLogger.class.getName();

    // Does the log4j version in use recognize the TRACE level?
    // The trace level was introduced in log4j 1.2.12.
    final boolean traceCapable;

    Log4JLogger(Logger logger) {
        super(logger.getName());
        this.logger = logger;
        traceCapable = isTraceCapable();
    }

    private boolean isTraceCapable() {
        try {
            logger.isTraceEnabled();
            return true;
        } catch (NoSuchMethodError ignored) {
            return false;
        }
    }

    /**
     * Is this logger instance enabled for the TRACE level?
     *
     * @return True if this Logger is enabled for level TRACE, false otherwise.
     */
    @Override
    public boolean isTraceEnabled() {
        if (traceCapable) {
            return logger.isTraceEnabled();
        } else {
            return logger.isDebugEnabled();
        }
    }

    /**
     * Log a message object at level TRACE.
     *
     * @param msg
     *          - the message object to be logged
     */
    @Override
    public void trace(String msg) {
        logger.log(FQCN, traceCapable ? Level.TRACE : Level.DEBUG, msg, null);
    }

    /**
     * Log a message at level TRACE according to the specified format and
     * argument.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for level TRACE.
     * </p>
     *
     * @param format
     *          the format string
     * @param arg
     *          the argument
     */
    @Override
    public void trace(String format, Object arg) {
        if (isTraceEnabled()) {
            FormattingTuple ft = MessageFormatter.format(format, arg);
            logger.log(FQCN, traceCapable ? Level.TRACE : Level.DEBUG, ft
                    .getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level TRACE according to the specified format and