protected  void doLog(Logger logger,
    String message) 
{
        if (logLevel == null) {
            logger.info(message);
            return;
        }
        if ("debug".equalsIgnoreCase(logLevel)) {
            logger.debug(message);
        } else if ("info".equalsIgnoreCase(logLevel)) {
            logger.info(message);
        } else if ("warn".equalsIgnoreCase(logLevel)) {
            logger.warn(message);
        } else if ("error".equalsIgnoreCase(logLevel)) {
            logger.error(message);
        } else if ("fatal".equalsIgnoreCase(logLevel)) {
            logger.fatal(message);
        } else if ("trace".equalsIgnoreCase(logLevel)) {
            logger.trace(message);
        } else {
            throw new IllegalArgumentException("LogLevel [" + logLevel + "] is not supported");
        }
}

Performs the actual logging.

 public String getLogCategory() 
{
        return logCategory;
}

 public String getLogLevel() 
{
        return logLevel;
}

 protected Logger getLoggerToUse() 
{
        if (logCategory != null) {
            if (categoryLogger == null) {
                // init category logger
                categoryLogger = LoggerFactory.getLogger(logCategory);
                if (logLevel == null) {
                    logLevel = "info"; // use info as default if not provided
                }
            }
            return categoryLogger;
        }
        return LOG;
}

Get's the logger to use.

 public String intercept(ActionInvocation invocation) throws Exception 
{
        if (! shouldLog()) {
            return invocation.invoke();
        } else {
            return invokeUnderTiming(invocation);
        }
}

 protected String invokeUnderTiming(ActionInvocation invocation) throws Exception 
{
        long startTime = System.currentTimeMillis();
        String result = invocation.invoke();
        long executionTime = System.currentTimeMillis() - startTime;
        StringBuilder message = new StringBuilder(100);
        message.append("Executed action [");
        String namespace = invocation.getProxy().getNamespace();
        if ((namespace != null) && (namespace.trim().length()  > 0)) {
            message.append(namespace).append("/");
        }
        message.append(invocation.getProxy().getActionName());
        message.append("!");
        message.append(invocation.getProxy().getMethod());
        message.append("] took ").append(executionTime).append(" ms.");
        doLog(getLoggerToUse(), message.toString());
        return result;
}

Is called to invoke the action invocation and time the execution time.

 public  void setLogCategory(String logCatgory) 
{
        this.logCategory = logCatgory;
}

 public  void setLogLevel(String logLevel) 
{
        this.logLevel = logLevel;
}

 protected boolean shouldLog() 
{
        // default check first
        if (logLevel == null && logCategory == null) {
            return LOG.isInfoEnabled();
        }
        // okay user have set some parameters
        return isLoggerEnabled(getLoggerToUse(), logLevel);
}

Determines if we should log the time.